The Official AVS Antenna Topic! [Text View] - Page 12

greywolf

09-20-05, 01:16 PM

Your situation meets the requirement for single point grounding perfectly. 8ga aluminum meets the NEC requirements as long as it is not run close to the earth until it gets to the rod. Check your local codes though as some places require copper. As for info on the subject:

http://www.mikeholt.com/documents/grounding/word/satellite.doc

http://archive2.avsforum.com/avs-vb/showthread.php?postid=3618667#post3618667 (may not be a valid link any more)

AVSforum member Signal posted the following helpful sites. Dish and antenna masts have the same grounding requirements.

National Electrical Code - Search for "dish" http://forums.nfpa.org:8081/necfaq/necsrch.htm

The information there also applies to antenna grounding. In the 2002 code update, if a water pipe is used, it must be all metal and connected to the electrical panel within 5ft of where the pipe enters the building. The connection to the pipe from the lightning arrestor/ground block and from the antenna/dish mast must also be within 5ft of the pipe's entry.

Preventing Damage Due to Ground Potential Difference
http://www.cinergy.com/surge/ttip08.htm

PSIHQ - Grounding Requirements
http://www.psihq.com/iread/strpgrnd.htm

PolyPhaser Technical Information
http://www.polyphaser.com/ppc_technical.asp

Tower Page - see N1LO's GUYED TOWER TOPIC SUMMARY
http://www.qsl.net/n1lo/tower.htm

BarnacleBill

09-20-05, 03:28 PM

So it appears that you are about a mile South of Sutro Towers in S.F. And about 4 miles North of KNTV (NBC Analog and Digital),which sits atop a 1000 foot hill with presumably a more or less unobstructed line-of-sight path
(give or take some local buildings that may be in the way).
From that close, their signals should be nearly as strong as from Sutro Tower.
[In which case moving the antenna around should have found a sweet spot free of multipath.]

Do you know for sure whether A-KNTV (CH11) and/or KNTV-DT (CH12) are broadcasting from their new location 4 miles away (per Change Proposal in FCC database), don't support this common conjecture
Holl_ands, thanks again for all the info, though I did not understand the part (not quoted) about the F connector with a short.

It seems that everyone talks about how effective an antenna is, in terms of gain. Gain is not an issue for me, obviously, since I'm practically on top of the towers. As you state, I need to reject the strong signal from Mt. Sutro (322 deg) to avoid multipath and IM while trying to get the signal from Mt. San Bruno (155 deg). Rabbit ears can't do this, I think, because it does not have large F/B ratio. So, is there such a thing as an indoor antenna with a large F/B ratio for VHF high band?

BTW, yes, I'm sure that KNTV is broadcasting from from the new location. For one, I get some picture and sound instead of nothing. A few other things: no attic; I'm fairly high compared to the overall area but in a low point in the neighborhood; it's a very hilly area, which is the main cause of multipath.

holl_ands

09-20-05, 09:49 PM

Holl_ands, thanks again for all the info, though I did not understand the part (not quoted) about the F connector with a short.

It seems that everyone talks about how effective an antenna is, in terms of gain. Gain is not an issue for me, obviously, since I'm practically on top of the towers. As you state, I need to reject the strong signal from Mt. Sutro (322 deg) to avoid multipath and IM while trying to get the signal from Mt. San Bruno (155 deg). Rabbit ears can't do this, I think, because it does not have large F/B ratio. So, is there such a thing as an indoor antenna with a large F/B ratio for VHF high band?

BTW, yes, I'm sure that KNTV is broadcasting from from the new location. For one, I get some picture and sound instead of nothing. A few other things: no attic; I'm fairly high compared to the overall area but in a low point in the neighborhood; it's a very hilly area, which is the main cause of multipath.

Maybe Analog KNTV moved but Digital KNTV-DT hasn't???

CH11/12 VHF antennas with good F/B are pretty big, as you can see by looking at these examples:
http://www.winegard.com/offair/pdf/ya-6713.pdf
http://www.antennacraft.net/Yagi.htm
Without an attic, it would have to go on the roof.

Shorting out the input to your HDTV, and then each RF Splitter and pieces of coax
in your downlead, will determine if they are causing leakage from local towers.

a. Type-F connector with a short: take just the center wire from a short piece of
RG-6 and fabricate a cable of zero length by leaving a piece down the center and
soldering it to the surrounding connector.

b. Type-F cable with a short: take a piece of left over RG-6 cable and chop off the
end with only a couple of inches of cable left.
Strip the cable and twist the ends together. Soldering is optional.

c. R-S 1156 Terminating Resistor (75-ohm) Type-F Connector:
http://www.radioshack.com/product.asp?catalog%5Fname=CTLG&product%5Fid=15-1156

d. Terminating Type-F connectors also available at most Home Improvement Centers.
They are normally used to cap-off unused RF Splitter ports.

Fletchdude

09-21-05, 09:55 AM

sregener

09-21-05, 11:20 AM

I saw a dish type antenna on the net for over-the-air UHF reception. Any experience with this type antenna? I have a lot of trees that mask my conventional antenna reception here in the DC-Baltimore area.

I've read very few good reviews of this antenna. It performs very poorly and has nothing that would fix your tree problems.

atye

09-21-05, 05:12 PM

Can someone please explain to me why my long distance reception is so much better at night than during the day? Will this situation likely improve with a better antenna? I've tried a search for this topic but didn't find much.

Ronin_R6

09-21-05, 05:37 PM

I have a few questions for the antenna gurus.

I live in a 3 story townhome and was planning on putting an antenna in the attic.
here are the stations i would like to recieve. (info taken from antennaweb)
AntennaType Call Sign Channel Compass Orientation Miles From Frequency Assignment
blue - uhf WRC-DT 4.1 94° 23.1 48
blue - uhf WTTG-DT 5.1 91° 23.2 36
blue - uhf WUSA-DT 9.1 92° 23.3 34
blue - uhf WJLA-DT 7.1 92° 23.3 39
violet - uhf WBDC-DT 50.1 91° 26.2 51

i have read good things about the Channelmaster items so i am debating between the CM-4221 or the CM-4221. the 4221 is half the price (for obvious reasons) so if it will be sufficient then I would like to with that. So will the 4 bay be enough, or do i need an 8 bay. or if neither will get it done then what route should i go.

Do i need a preamp. The signal will have to fed down to the first floor which is a pretty far run. it will later have to be split to feed a second tuner.

It will be connected to a dish 811 for now. and i am looking to upgrade the my 511 to a 942 which is what will run the other TV

did I leave out any vital information?

Thanks for any help.

Matt

Neil L

09-21-05, 06:38 PM

Can someone please explain to me why my long distance reception is so much better at night than during the day?http://www.geocities.com/toddemslie/UHF-TV-DX.html
Will this situation likely improve with a better antenna? I've tried a search for this topic but didn't find much.No, a better antenna won't change the factors that cause better reception after sundown. But, an antenna with higher gain will have...well...more gain under all conditions. But if you don't have much or any signal reaching you during the day, more gain won't help. You know, 12 X 0 = 0.

Neil L

09-21-05, 06:42 PM

So will the 4 bay be enough, or do i need an 8 bay. or if neither will get it done then what route should i go.
My guess would be that the 4-bay will be fine. These bowtie type antennas are excellent in attics.

Do i need a preamp. The signal will have to fed down to the first floor which is a pretty far run. it will later have to be split to feed a second tuner.Probably not. I'd try it first without the preamp. If you find you need one you can always add it later. But as close as you are to the transmitters, you would likely have trouble with a preamp being overloaded by the signal.

Ronin_R6

09-21-05, 08:37 PM

thanks for the info Neil. I didnt realize that the pre-amp could actually cause problems. I was leaning to the 4 bay myself but its always nice to get some reassurance.

thanks again

AntAltMike

09-21-05, 09:07 PM

There aren't too many situations where a preamp driven by an attic 4-bay bowtie is going to get overloaded by transmitters that are 23 miles away, though Ronon_R6 probably doesn-t need one.

If Ronon_R6 is only concerned with receiving Washington market stations, but he favors attic installation, then he still probably should spend the extra $30 for the 8-bay bowtie, which will also give him a better shot at Annapolis WMPT, but realistically, the difference between excellent and poor reception will be just the roll of the dice, determining what obstructions are between him and the transmitters.

Ronin_R6

09-21-05, 09:56 PM

I am not really concerned about any stations other then the 4 networks, and maybe WB50.

But is it better safe then sorry? meaning should i just get the 8 bay to be on the safe side? its not like $30 is going to break the bank or anything.

Also what type of cable should i run? RG-6?

MHD1080

09-22-05, 01:46 PM

New Here! But Is There A Way To Combine 2 Uhf Antenna S Together Instead Of Using A Rotor ,my Chaneels Are In 2 Different Directions

MHD1080

09-22-05, 01:47 PM

Also I Am On A Hill And The Stations Towers Are On The Other Side,any Idea's Of Away To Pick Up Better Signal?

holl_ands

09-22-05, 03:13 PM

New Here! But Is There A Way To Combine 2 Uhf Antenna S Together Instead Of Using A Rotor ,my Chaneels Are In 2 Different Directions

There are several ways to combine two UHF antennas pointed in different directions:

1. Standard RF Splitter/Combiner, which incurs about a 4 dB loss in sensitivity
(with optional Preamp on combined output).

2. Preamp for each antenna so don't lose sensitivity and then combine the two amplified signals
using an RF Splitter/Combiner that has DC PASS on both ports
(e.g. Zenith ZDS5010) in order to provide power to both Preamps.

3. Low Loss (0.2 dB) Stripline Antenna Coupler (with optional Preamp on combined output),
such as the $100 Lindsay:
http://hdtv.forsandiego.com/messages/1/2780.html#POST15877
Some examples:
http://hdtv.forsandiego.com/messages/1/2780.html#POST16670
http://hdtv.forsandiego.com/messages/1/3272.html#POST18916
http://hdtv.forsandiego.com/messages/1/3673.html#POST19479

A Preamp should not be used when broadcast towers are within about 20-30 miles
(and maybe less if you are behind a hill, or use indoor/attic antenna):
http://hdtv.forsandiego.com/messages/1/2846.html?1126998999

When you combine two antennas, you also pick up more undesirable multipath reflections
than a solitary antenna and increase the noise floor a few dB.
So not all people have been successful.

=======================================================
An inexpensive alternative that avoids these problems is to use an RF A/B Switch
(e.g. R-S 1968) and simply switch between two coax downleads:
http://www.radioshack.com/product.asp?catalog%5Fname=CTLG&category%5Fname=CTLG%5F003%5F010%5F011%5F000&product%5Fid=15%2D1968
Of course, that makes channel surfing and PVR recordings much more difficult.

One more: if the stations are generally opposite each other (180 degrees +/- 30 degrees)
and not too far away, then the rear screen on a CM-4221 4-Bay Antenna could be removed,
turning it into a modest gain bi-directional antenna.

=======================================================
PS: A search for "Stacked Antenna" arrangements will yield additional solutions
if the antennas are pointed in the SAME direction, .

tasm

09-22-05, 03:35 PM

Does anyone know anything about the terk tv55 hd antenna? Can you hook it up to a d-vhs recorder or hi def hard drive recorder? The antenna is so small (46in long) that it doesn't seem like it would pull in a strong enough HD signal.It says you can mount it under your window seal.But i also see these HD antenna's that are like 5ft tall. I don't want an eyesore on my roof.

greywolf

09-22-05, 04:13 PM

The thing is awful. Good antennas look like antennas have looked for decades.

Jams

09-22-05, 07:12 PM

Rack

09-22-05, 09:33 PM

Looks like MAX HD is at it again:
http://community-2.webtv.net/GregBarker/NewTowerAntennas/
That VHF-hi horizontal stack is new, I believe.

holl_ands

09-22-05, 09:37 PM

Greetings all-

I am helping a friend in Eugene, OR finally jump into the HD world. According to antennaweb, he has DT stations locally all under 10 miles away, no major obstructions, but the channels are split - some are at 35 degrees and some are at 131 degrees. He has Dish with the 942 HD tuner and I was originally going to get him the Winegard SquareShooter but I cannot get any good info on whether this thing can deal with teh slip in direction of the stations. I like the squareshooter becasue it can attach to his dish. Suggestions?

Thanks!

SquareShooter beamwidth is quite wide: 68 degrees for lower UHF channels,
decreasing to 54 degrees for upper UHF channels.
But you would be working some of the channels on the back side of the antenna.

The CM4221 4-Bay Antenna with the rear screen removed would be a much better,
higher gain, bidirectional antenna.... and much less expensive.

The Channel Master StealthAntenna is also bi-directional, but with a lot less gain
than the CM4221.....actually it has about as much gain as the SquareShooter.

You could also consider a two antenna arrangement as was discussed just a few posts ago....

Jams

09-23-05, 11:54 AM

SquareShooter beamwidth is quite wide: 68 degrees for lower UHF channels,
decreasing to 54 degrees for upper UHF channels.
But you would be working some of the channels on the back side of the antenna.

The CM4221 4-Bay Antenna with the rear screen removed would be a much better,
higher gain, bidirectional antenna.... and much less expensive.

The Channel Master StealthAntenna is also bi-directional, but with a lot less gain
than the CM4221.....actually it has about as much gain as the SquareShooter.

You could also consider a two antenna arrangement as was discussed just a few posts ago....

Well I was a little off. The spread of the DTV channels is less than 90 degrees so it seems if he pointed the squareshooter in the middle of them it's only looking just less than 45 degrees left or right for the signal.

I did not know that by removing the back screen from teh bowtie antenna that it would make it a bidirectional thing but since we're at just less than a 90 degree split would that really work? I don't think two antennas is a choice.

What about the clip on ones that terk and phillips make? They seem to be omnidirectional and since he's so close as long as it's up high enough I think that would work. Plus they have the built in dual diplexer which is good for him. He's not yet ready to run another line into the house.

Jams

09-23-05, 12:13 PM

If I got something like the Channel Master 3014 or 3016, would he have to rotate it to get both sets of signals or would it pick them all up (assuming it's installed rooftop high enough without obstructions)?

tasm

09-23-05, 02:18 PM

What is the smallest antenna i can get that will still pull in good signals?

amirm

09-23-05, 02:22 PM

What is the smallest antenna i can get that will still pull in good signals?
Simple piece of wire! If the stations are good and strong, you really don't need much. I have just a wire hanging on the back of my media center PC's HD tuner card and I get just about all the digital channels in Seattle area! But then we are on a hill with a direct view of Seattle towers....

Amir

holl_ands

09-23-05, 02:32 PM

Well I was a little off. The spread of the DTV channels is less than 90 degrees so it seems if he pointed the squareshooter in the middle of them it's only looking just less than 45 degrees left or right for the signal.

I did not know that by removing the back screen from teh bowtie antenna that it would make it a bidirectional thing but since we're at just less than a 90 degree split would that really work? I don't think two antennas is a choice.

What about the clip on ones that terk and phillips make? They seem to be omnidirectional and since he's so close as long as it's up high enough I think that would work. Plus they have the built in dual diplexer which is good for him. He's not yet ready to run another line into the house.

Here is some info on antennas with wide beamwidths:

W-G SquareShooter: SS-1000 (no Preamp) or SS-2000 (with Preamp)
http://www.winegard.com/offair/s2shooter/WC-811.pdf
When I blow up the scale, I see that it uses a field polar plot (volts/meter),
rather than the usual dB scale.
So 3 dB down is at 0.707, i.e. 20*log(0.707) and 6 dB down is at 0.5.
At +/- 90 degrees, it's down about 5 dB from maximum gain for low channels,
and about 8 dB for upper channels.
W-G says the average UHF gain is about 4.5 dB, so you have about -0.5 to -3.5 dBd gain
in two desired directions and about 4.5 dBd gain in undesired direction.
Fol. is NEC Simulation for SquareShooter:
http://www.hdtvprimer.com/ANTENNAS/SquareShooter.html
It shows that +/- 45 degrees is about 6 dB down on the sidelobes.

W-G Sensar III: GS-1100 (no Preamp) or GS-2200 (with Preamp) is much lower cost.
http://www.solidsignal.com/manuals/WC-810.pdf
Note that at VHF it is bi-directional, whereas at UHF it is unidirectional.
This is also a field polar plot (volts/meter) rather than the usual dB scale.
At +/- 90 degrees, it's down about 5 dB from maximum gain
(give or take a little due to the skewed response and pointing inaccuracies.
W-G doesn't say what the maximum gain is, but it must be less than 3 dBd.
So the net gain is -2 dBd in desired directions and + 3dBd in undesired.

C-M StealthAntenna:
https://www.solidsignal.com/prod_display.asp?CAT=&PROD=ANC3010
Gee, they don't say much...but antenna pattern is probably similiar to Sensar III.

Either of these antennas are much lower cost alternative to the SquareShooter
and all will perform about the same.

Note that omnidirectional antennas (e.g. W-G MS-2000 MetroStar and MX1405 Maxus)
will have about 0 dBd gain in all directions, but do not provide suppression of multipath in any direction.
Suppression of multipath being reflected into the "back" side of the antenna is highly desirable.

tasm

09-23-05, 11:02 PM

may012

09-24-05, 02:59 AM

I am trying to get OTA HDTV set up, but I'm having some problems with it. I'm hoping that somebody here can help me out. I am in the Boston area, and according to antennaweb I'm located about 7 miles away from the broadcast towers (and they're all in the same direction too).

I bought an HDTV tuner for my computer, and I went to Radio Shack today and bought a simple rabbit ears antenna with modest amplification (model 15-1838) to test it out. Even if I don't turn the amplifier on, my computer reports that I am receiving a strong signal (between 90% to 100%, whatever that means), but every 10 to 30 seconds, the signal will go out. The disturbances can be momentary or they can last up to 5 seconds before the feed comes back.

After reading stuff online today about antennas, I am assuming that the problem results from multipath issues. Does that sound right to everyone else?

If so, I've read that the standard UHF loop does a very poor job of isolating a single direction. I would be interested to hear ideas from everyone about any antenna that focuses well on a single direction. So far I am looking at the Silver Sensor and also the Radio Shack model 15-1880 antennas, but I'm open to other suggestions as well.

bobchase

09-24-05, 05:02 PM

Holl_ands & srenger

While sitting here waiting for Rita to steam roller over the station (she didn't), I collated some antenna data that I took last week. The antennas were all tested at the same place, on the same day, at the same hight. This time I used averaging to optimize for the DTV channels because I was looking for multipath or, specifically, multipath reduction from antenna to antenna. In previous testing, I had used the 'MAX HOLD' function to capture the peak of the NTSC carriers so I could get more measurement points to graph. However, MAX HOLD tends to mask the multipath ripple because it captures the DTV peaks also. Unfortunately, my neighborhood does not lend itself to that kind of testing as multipath there seems to be minimal.

I wanted to get a new baseline on all of the antennas for this winters attic & antenna testing. I have two people that I have promised a visit and both are at the far side of the DTV reception for the station. One is in Winnie, TX (and I hope he is OK after the storm). The other is just west of Conroe, TX. I wanted to see how the new antennas performed against the old favorites.

If you want to do any calculations with this data, the actual DTV average power received at the STB is 17.61 dB above the measured (charted) levels. The levels shown on the charts are because of the 100 kHz RBW of the spectrum analyzer.

Bob Chase
KHWB-TV

holl_ands

09-24-05, 05:59 PM

If I read it right, it looks like UHF antennas with highest gain were:
1. CM4248, C-M "Diamond", UHF Corner Yagi
2. CM4228, C-M UHF 8-Bay Bowtie with Reflector Screen
3. CM3671, C-M "Crossfire", Hybrid VHF LPDA, UHF Yagi

in the middle:
4. 91XG, Antennas Direct, UHF Corner Yagi with 22 Bowtie Elements
5. 1469B, Scala, UHF LPDA inside a Radome Enclosure

and those with the least:
6. CM5646, C-M "Super-V", VHF Forward Swept "V", UHF Corner Yagi
7. HD7210, W-G "Ghost Killer", VHF/UHF Classic Yagi
8. SS1000, W-G SquareShooter, VHF/UHF Spiral Log Periodic

with the SquareShooter separated by several dB below the group.
It also was a terrible VHF antenna, contrary to W-G published claims.
So why would anyone buy one, other than it "matches" their SAT dish???

As expected, the CM4228 8-Bay Bowtie wasn't as good a VHF antenna as a
purpose-build VHF antenna, but it was only a few dB below the VHF/UHF Combos
for upper VHF (CH7-13) and finally dropped off for CH2-6.

Of course, this only addresses the gain parameter and not F/B and multipath rejection,
but since gain is obtained by narrowing the antenna pattern, they are related.

=========================================================
PS: Note typos on first page: "HD7120" should be "HD7210".
and Antennas Direct usually calls their biggest antenna the "91XG",
(although their home page calls it the "XG91" ....go figure....)

Any explanation as to why Scala LPDA would have a significantly higher noise floor,
such as in Business Radio and other regions?

holl_ands

09-24-05, 06:10 PM

holl_ands

09-24-05, 06:36 PM

Simple piece of wire! If the stations are good and strong, you really don't need much. I have just a wire hanging on the back of my media center PC's HD tuner card and I get just about all the digital channels in Seattle area! But then we are on a hill with a direct view of Seattle towers....

What type of wire?Just standard coax cable,or special antenna wire?And will i be able to hook it up to a HD recorder to record HD?If i run a wire up the chimney, Do i have to expose the wire end?If it rains will it damage anything?

question for holl_ands below,

If i get the squareshotter ant. ,Isn't puting it in the attic under a roof going to block and sort of weaken the signal? Can i hook a squareshooter up to a HD recorder? I don't know anything about antennas,so forgive me if i sound stupid.

You need to tell us where you are located. Preferable zipcode and nearest cross streets.
You should also punch this info into www.antennaweb.org to see what kind of antennas/preamps they recommend.

Putting an antenna 20+ feet above your roofline is always "best".
After that, it's a compromise process, depending on how much excess signal you have to begin with.

There is an antenna height loss the lower you go.
There is also an indoor/attic loss that depends a lot on your house construction.
See Bob Chase's earlier post re Outdoor vs Indoor measurements in his very lossy attic:
http://www.avsforum.com/avs-vb/showthread.php?p=5410432#post5410432

And indoor/attic locations suffer the third whammy of strong multipath with short delay echos
(the worst kind of multipath for most receivers).

SquareShooter??? Overpriced, underperforming, need I say more....
HDTVi and Silver Sensor, uhhhh.....they're small and cheap (see amazon.com).
But if you are close to the towers and don't mind fussing with the antenna.....

Up the chimney? You gotta be kidding.....
It's a Fire code violation, and your insurance co. won't cover your loss if you get hit by lightning.
See fol for installation guidance:
http://www.solidsignal.com/manuals/AntInstallGuide.pdf
Note that indoor/attic antennas do NOT have to have lightning arrestors, etc.

The television signal from the on-air antenna can be fed to both the HDTV and the antenna input
on a recorder by using an RF Splitter, which results in another 4 dB of loss.
See for example the R-S 15-1234, but look around for a better price.

If you want to record the HD DTV signal, you need a recorder that will record HD signals:
http://www.avsforum.com/avs-vb/showthread.php?t=508907
What equipment do you have now?

Geo05

09-24-05, 06:43 PM

Simple piece of wire!
What type of wire?Just standard coax cable,or special antenna wire?

Any bare wire (inexpensive "rabbit ears" are a good choice). :)

Any wire intercepting a radio wave will generate a bit of electricity (at a matching frequency) - thats how antennas work.

To get a basic understanding of this, check out this link (http://www.kyes.com/antenna/dipole.html).

bobchase

09-24-05, 07:00 PM

Holl_ands
I have yet to find a measurement method for multipath that I would feel confident putting on the web. For FTB, just turning the antenna around and measuring is not sufficient. (I made that mistake already.) The reflections from the surrounding environment cause too many errors. So it would take a day (a morning at least) and another truck to cut patterns against a fixed transmit antenna. The transmitter, fed into a channel cut dipole, at the same height, located close by, with enough power to swamp out any reflections that the receive antenna would pick up. In the end, we would have a table similar to the CM & WG FTB tables. Do you think it is worth it?

The Scala data was taken in the morning at 1138. Then I did some CM7777 overload testing. In the late afternoon, between 1500 & 1700 I flew the antennas. The only reason I can think of for the variance is that the noise floor changed from the morning to afternoon. It doesn't seem likely, but I can't think of any other reason for the variance.

Normally, I take a Scala measurement 1st & last during testing to compare them. This day, the final measurement was taken with the wrong input attenuation, so the last measurement incorrectly shows the Scala with significantly less noise than the rest of the field. :mad: All of the measurements were taken at 100 kHz RBW, 30 kHz VBW, and 0 dBm reference level. What you see on the chart for the Scala is the 1st measurement of the day.

The square shooter has a very high WAF (Wife Acceptance Factor). When I have been invited to customers' homes for antenna testing, she always asks 'won't that one work just as well as the rest?'. They will even ask this as I unload the truck, way before I ever run one up the mast. The runner up for WAF is the CM5646/CM3016. By the way, the SS1000 is the only antenna I have that consistently shows measurable multipath in the signals.
Bob C

MAX HD

09-24-05, 08:02 PM

Looks like MAX HD is at it again:
http://community-2.webtv.net/GregBarker/NewTowerAntennas/
That VHF-hi horizontal stack is new, I believe.

Yep,it's a recent arrangement and I'm glad it was in the air when I picked up KMBC-DT-7 in KCMO.There were at least four other CH 7's that had to be nulled! This is the most load I've had on a CM rotor(2 8lb-13ft ants 6ft apart),but it seems to be handling it just fine.

With the crank-up/tilt-over tower and the swing-up mast it only takes a couple of minutes to get things down and change stuff around.There's no end to it :-)

BTW,if someone wants to do a UHF Quad that lives in the middle of nowhere,I've got a Lindsay combiner that I'm not going to put back in the air.It will produce maximum gain hands-down,but not good for Dxing.Pm me if interested,or send an email from my webpage.

Greg B

amirm

09-24-05, 08:29 PM

What type of wire?Just standard coax cable,or special antenna wire?And will i be able to hook it up to a HD recorder to record HD?If i run a wire up the chimney, Do i have to expose the wire end?If it rains will it damage anything?
This has been mostly answered. But just to be clear... No, you don't need to run the wire anywhere. You just need a few feet of it behind the set. Move it around until it works and then tape it to something so it doesn't move.

The wire must be unshielded so coax does NOT work. If you do want to use coax (which you probably have to since you will have a hard time inserting anything in the center pin of the tuner input), then just solder 4 to 6 feet of any wire you have sitting around to the center pint of the coax.

Some equipment used to come with spit wire (T shape) antennas that you served the same purpose. You may want to see if you have one sitting around from an old TV or VCR....

Note that the above is a poor man's antenna (I can just see the RF experts here cringing after they read the above explanation :)). You are really better off getting a small indoor antenna. I just said mentioned the above choice since you said you are very close to stations....

Amir

deconvolver

09-24-05, 10:37 PM

[QUOTE=holl_ands]...
Of course, this only addresses the gain parameter and not F/B and multipath rejection,
but since gain is obtained by narrowing the antenna pattern, they are related.
...
QUOTE]
I think Bob Chase's test was showing net gain not raw gain so a low signal level measurement does not necessarily mean a poor antenna pattern; it could also mean a poor impedance match (high VSWR) which is the reason most UHF antenna's have much less signal than a dipole in the VHF band.

hardballpete

09-25-05, 11:50 AM

Anyone try/using this new antenna, which is new on the market?

Supposed to be at Best Buy, but I can't find one in my local store.

Any feedback?

holl_ands

09-25-05, 07:01 PM

Is there a DIY for antennas to build your own UHF antenna?

I have seen web pages for HAM stuff but I haven't located a resource for a kit or make your own.

Just ran across the fol DIY TV antenna: it's a narrowband UHF Yagi:
http://mysite.verizon.net/vandeb/hdtv_web/hdtv_ant.html

thr3

09-26-05, 11:56 AM

Back to Greywolf on grounding (I was sidetracked from this project by Rita - fortunately no damage)

Thanks for all the help. I thought I was ok, until I saw the part about the lead in not running close to the physical ground. Unfortunately mine does. This may be a tough one to get right because I am in a townhouse and the ground lead is running under the gate to my patio to get over to the single point ground rod that the electrical box and phone are tied to.

I could add another ground rod (not easily) to avoid this, but then I don't get the single point tie in.

Sorry for all the questions. Youv'e been a great help.

greywolf

09-26-05, 01:13 PM

Just use a copper wire for the ground lead. Only aluminum is to be kept away from the earth.

toneman

09-26-05, 06:48 PM

Anyone try/using this new antenna, which is new on the market?

Supposed to be at Best Buy, but I can't find one in my local store.

Any feedback?
My next door neighbor has one of those; he claims that he can pull in some stations but not others, and even then, he's not getting a pretty strong signal w/ it. OTOH--when he asked me how my $24.99 Radio Shack 15-2160 outdoor antenna was working and I told him that it can pull in all of the local OTA HD stations...boy, you should have seen the look on his face! Maybe it was because he paid $150 for something that's not completely doing what he was hoping it would do, while in the meantime his next-door neighbor (me) is enjoying local OTA HD programming in all its glory with a $25 Radio Shack antenna!

Just to make one thing clear--I'm not saying that this Terk "Squareshooter-like" antenna is a piece of junk...it may very well work for others, depending on location/distance. But given my anecdote (above), the Radio Shack turned out to be a much better choice, both performance- and cost-wise. :D

Geo05

09-26-05, 07:40 PM

Note that the above is a poor man's antenna (I can just see the RF experts here cringing after they read the above explanation :)).

Amir

This is probably a better choice than those "dishes" that are being sold for UHF reception. :)

Am no expert on this topic, but the typical UHF radio signal has a wavelength in the order of 3-feet. It is hard to understand how a small ''dish" antenna can work effectively here.

The typical sattelite transmissions on the other hand are microwave signals (wavelength less than 1-ft) that may quite readily be focussed into an LNB (or horn) using a 2-ft dish.

holl_ands

09-26-05, 08:10 PM

My next door neighbor has one of those; he claims that he can pull in some stations but not others, and even then, he's not getting a pretty strong signal w/ it. OTOH--when he asked me how my $24.99 Radio Shack 15-2160 outdoor antenna was working and I told him that it can pull in all of the local OTA HD stations...boy, you should have seen the look on his face! Maybe it was because he paid $150 for something that's not completely doing what he was hoping it would do, while in the meantime his next-door neighbor (me) is enjoying local OTA HD programming in all its glory with a $25 Radio Shack antenna!

Just to make one thing clear--I'm not saying that this Terk "Squareshooter-like" antenna is a piece of junk...it may very well work for others, depending on location/distance. But given my anecdote (above), the Radio Shack turned out to be a much better choice, both performance- and cost-wise. :D

Is the SS-3000 Sharpshooter (usually an indoor antenna) being compared to an outdoor antenna?

Hardly a fair test of the antenna itself if one is indoors and the other 30 feet in the air.....

mgtr

09-27-05, 07:58 PM

I have used the CM 4228 with great success (in SC) but I thought the wind load would be a little much in Fla. So, I used the Square Shooter 1000, with the CM 7777. It is definitely overpriced, but doesn't cause apoplexy among the HOA people. The combination works great at about 50 miles, but I had to cut a separate VHF antenna (simple) for one channel (11), which I mounted to the top of the antenna.
There may be better combinations, but mine works.

MrMolding

09-28-05, 10:00 AM

Ronin_R6:

I live in South Riding and I've used both a Channel Master 4228 and 4248 in my attic. I have a long run to my basement from the attic and I use a splitter to feed three boxes back into different parts of the house. I get everything in DC and some Balitmore on stormy nights. Sometimes I get Hampton, VA as well.

The 4248 is a little better at getting everything in DC but the 4228 is better at pulling in Baltimore but it loses 26.1 if I try to point between the two cities.

Both configs needed a 7777 preamp. I get nothing without it due to the long runs, but it works for me.

Good luck!

Geo05

09-28-05, 10:49 AM

Ronin_R6:

I get everything in DC and some Balitmore on stormy nights.

Could you please clarify. You mean all UHF, no VHF, right..? :)

jdmac29

09-28-05, 11:39 AM

I have a Samsung SIR TS 360 directv hd receiver. I have the biggest radioshack uhf/vhf antenna. When I tune into the CBS, ABC, NBC the receiver shows Dolby Digital sound available but my Pioneer VSX451 dolby digital receiver will not decode the sound into Dolby Digital all the time. CBS primetime shows it did but other stations it says DD but the receiver does not decode it. It stays dolby prologic II. I am using a 6 ft Phillips high end fiber optic cable.
I don't feel it is my equipment since it works great with DVD/Satellite PPV movies broadcast in DD, but does each channel need to be fine tuned to get enough signal for the dobly digital to be decoded.
Any help would be appreciated.
Thanks
Jdmac29

greywolf

09-28-05, 11:53 AM

See another sticky trhread at http://www.avsforum.com/avs-vb/showthread.php?t=422073 to check which of your local stations are broadcasting 5.1 DD. Remember all DTV sound is DD but not all DD is 5.1 DD. There are many flavors from 1.0 to 5.1 and 2.0 which many local stations are delivering because they are not 5.1 capable is treated by many receivers as Prologic. Even if a local station can deliver 5.1, the program material may not be coded in 5.1 sound. If you get reception, you are getting the the full stream. Signal strength problems will show up as either video blocking and sound pops/dropouts for borderline signals or no picture and sound.

kflorek

09-28-05, 12:07 PM

Do horizontally close TV antennas, say 15 feet between, interfere?

I notice there are some very technical people here who might give me a handle on what to expect.

I am putting two rotatable antennas on the roof, so that two users will be able to watch independently, but the masts can't be located very far apart due to the situation. (It is a hip roof with not that much top ridge. I will use the chimney for one mount, and a tripod for the other.) The antennas will often be aimed at where most of the stations are grouped, so one will be close to being aimed at the other. Will this make a mess out of the signal (multipath)? If so, what can be done to help, if anything?

There is a bedroom wing (also a hip roof) that I could also put the tripod on. It is 3 1/2 feet lower, but that could offset the antennas about 6 feet perpendicular to where the major stations are. Would that location help?

The major stations are located about 12 miles away. I am completely surrounded by 50-foot-plus trees (none mine) except for about 20 degrees, which (luckily?) is almost where the major stations are if I mount the antennas as far to one end of the roof as possible. I usually can't get a lock on the HDTV signals during the day for long, but frequently can get two (out of seven) at night from an indoor or attic antenna. On analog, the signal looks strong, but lousey; no snow, but terrible multipath images.

MrMolding

09-28-05, 12:21 PM

Could you please clarify. You mean all UHF, no VHF, right..? :)

Actually, I do get fairly good VHF with the 4228. I get 4, 5, 7, and 9. I forget the 4248's VHF response but it wasn't too terrible.

Good point! But, when the analog is turned off, my setup should be ok if they switch back to the other range.

cpcat

09-28-05, 02:16 PM

Do horizontally close TV antennas, say 15 feet between, interfere?

There's no guarantee both spots will give good reception, but they shouldn't interfere with each other at that distance at least above channel 3. Spacing of at least one wavelength is the general rule. This has to be element-to-element, not center-to-center when you are trying to prevent any possibilty of interaction. Channel 2 is around 18 feet , so that should be more than enough spacing for all but maybe ch. 2 and ch 3. For everything except low band vhf (2-6), 60 inches should be plenty.
Wavelength table: http://www.kyes.com/antenna/rabbitear.html
More info on antenna interaction: http://www.kyes.com/antenna/stacking.html

In practice it seems to be possible to cheat on this rule some, so most likely you're fine for all channels.

AntAltMike

09-28-05, 04:27 PM

Actually, I do get fairly good VHF with the 4228. I get 4, 5, 7, and 9. I forget the 4248's VHF response but it wasn't too terrible.

Good point! But, when the analog is turned off, my setup should be ok if they switch back to the other range.

4 analog in Washington, DC is broadcast digitally on 48, 5 is on 36, 7 is on 39, and 9 is on 34.

MrMolding

09-28-05, 04:42 PM

4 analog in Washington, DC is broadcast digitally on 48, 5 is on 36, 7 is on 39, and 9 is on 34.

Correct. What I meant was that when analog is turned off and everything is digital, I was under the impression that the UHF channels that handle digital for the current analog 4, 5, 7, and 9 will be given back and the current VHF slots will become digital.

holl_ands

09-28-05, 07:23 PM

In Feb05 Channel Election Results (see FCC website), CH 4 and 5 decided to keep their
new UHF assignments,
whereas CH 7 and 9 will revert back to original VHF assignments.

Next round results are expected soon, but don't expect too many changes.

Note that many stations are vacating CH2-6.

Jams

09-29-05, 12:00 PM

deconvolver

09-29-05, 12:51 PM

I have a firiend that I am helping get setup for OTA HD respetion. His two issues are that his stations are split between two arrays at a 90 angle and he is also on the wrong side of a hill and has many tall trees around the house. But he is only 3 miles from one set of stations and 9 miles from the other. We tried installing one of the supposedly omni-directional antennas that clips to his Dish but that didn't work well. We bought an amplified set-top thing that got some stations better and some worse. So now I have ordered for him a DB2 bowtie from Antennas Direct. They claim it has a 90 degree signal path and works very well when your stations are in different locations. Is this true of all bowties? I thought they were mostly very directional. I know this model is more expensive than the CM bowties but buying direct from AD gives me the option to return it for only the cost of return shipping if it doesn't work.

Anyone have thoughts/experiences with the DB2 or know about directionality of bowties? I have a bowtie on my roof and it seems very directional.

Thanks!
A bowtie like most antennas is not omnidirectional but if you point it between two stations that are 90 degrees apart you may get enough signal in each for it to work. If you point it directly at one station then the signal at 90 degrees will be very weak. There could be problems with multipath or being under the beam from 3 miles away. Check the analog stations and see if some channels have a ghost offset from the main image. If so then you may need enough directionality to select only one path. An amplifier could make things worse if the signals are too strong- look for a wavy herringbone pattern on analog channels to see if strong overload is present. The best solution may be two directional antennas with a switch to select which one to use but that won't work well for him if he has a Tivo. You also need to know if all the digital stations are UHF, if not then an antenna like rabbit ears that can work for VHF will need to be included.

toneman

09-29-05, 03:06 PM

Is the SS-3000 Sharpshooter (usually an indoor antenna) being compared to an outdoor antenna?

Hardly a fair test of the antenna itself if one is indoors and the other 30 feet in the air.....
My bad--I got mixed up between the SharpShooter and the SquareShooter... :D

But my anecdote comparing my neighbor's results with the Terk (Winegard SquareShooter SS-1000 equivalent) to that of my cheap RatShack antenna still stands. ;)

JStew

09-29-05, 10:23 PM

Anyone try/using this new antenna, which is new on the market?

Supposed to be at Best Buy, but I can't find one in my local store.

Any feedback?
I purchased one about a month ago and am pretty happy with it. I live in the Dallas area, approx 35-40 miles from the "antenna farm" in Cedar Hill and it seems to do a pretty good job. I previously had a Silver Sensor, but obviously couldn't receive the one VHF station I need (for MNF). The Sharpshooter picks up both VHF and UHF, so I'm a happy camper. Not a bad antenna for about $80.00.

mvita

09-29-05, 11:00 PM

mgtr, could you possibly provide some details on your VHF enhancement to the Square Shooter? I also have a SS-1000 and a CM 7777. I'm about 38 miles from the Orlando digital towers, and I'm having trouble reliably picking up the NBC affiliate (WESH-DT, VHF 11). I'd like to add a simple folded dipole to pick up VHF 11. I'm particularly interested in what you did re: weatherproofing the dipole, and also any mounting advice you might have.

sregener

09-30-05, 12:48 PM

This time I used averaging to optimize for the DTV channels because I was looking for multipath or, specifically, multipath reduction from antenna to antenna.

Hmmm. Looking over the chart, I must say I'm confused and/or disappointed with the results. I've had a pair of 4248s up on my roof, and they didn't impress me. (I also tried just one, instead of both, and was even more unimpressed.) And the Channel Master 3671 is a fine antenna, but it is a combo which means that it has to compromise a bit on the corner reflector, so I'd expect it to be dramatically inferior to the UHF-only antennas for UHF reception. Somehow, it scored nearly as high as the 4248 and 4228s.

But your results turn those assumptions on their head.

Of course, digital reception is more than gain, and I don't understand the methodology you used (I'm a hobbyist, not an engineer) to try to balance the factors involved. Nevertheless, the chart is interesting...

bobchase

09-30-05, 02:41 PM

Hmmm. Looking over the chart, I must say I'm confused and/or disappointed with the results. I've had a pair of 4248s up on my roof, and they didn't impress me. (I also tried just one, instead of both, and was even more unimpressed.) And the Channel Master 3671 is a fine antenna, but it is a combo which means that it has to compromise a bit on the corner reflector, so I'd expect it to be dramatically inferior to the UHF-only antennas for UHF reception. Somehow, it scored nearly as high as the 4248 and 4228s.

But your results turn those assumptions on their head.

Of course, digital reception is more than gain, and I don't understand the methodology you used (I'm a hobbyist, not an engineer) to try to balance the factors involved. Nevertheless, the chart is interesting...
sregener,
I too was surprised by the 4248 data. In fact, I went back to the raw data twice to make certain that I had not transposed the raw data between antennas. From past experience, I would have expected it to have a mid-range performance curve. Next month, when I check some of these antennas out at edge of the DTV signal, we'll see if the peck'n order changes.

When you see the 3671 close up and you just focus on the UHF portion, there is a lot of UHF antenna there. The only antenna I ever installed that matched the 3671's performance in the field was the biggest Quantum series antenna CM made. (1161B?)

Bob Chase

governorb

09-30-05, 04:29 PM

Whats does this mean?

DTV Antenna
Type Call Sign Channel Network City State Live
Date Compass
Orientation Miles
From Frequency
Assignment
* yellow - uhf KOCE-DT 50.1 PBS HUNTINGTON BEACH CA 353° 32.6 48
* green - uhf KDOC-DT 56.1 IND ANAHEIM CA 352° 32.7 32
* green - uhf KCBS-DT 2.1 CBS LOS ANGELES CA 352° 33.0 60
* green - uhf KTLA-DT 5.1 WB LOS ANGELES CA 353° 32.6 31
* green - uhf KAZA-DT 54.1 AZA AVALON CA TBD 353° 32.7 47
* lt green - uhf KLCS-DT 58.1 PBS LOS ANGELES CA 353° 32.5 41
* lt green - uhf KVEA-DT 39 TEL CORONA CA TBD 353° 31.8 39
* lt green - uhf KXLA-DT 44.1 IND RANCHO PALOS VERDES CA 352° 32.7 51
* red - uhf KRCA-DT 62.1 IND RIVERSIDE CA 353° 31.8 68
* red - uhf KTTV-DT 11.1 FOX LOS ANGELES CA 353° 32.5 65
* red - uhf KMEX-DT 34.1 UNI LOS ANGELES CA 352° 32.7 35
* red - uhf KCAL-DT 9.1 IND LOS ANGELES CA 352° 32.7 43
* red - uhf KNBC-DT 4.1 NBC LOS ANGELES CA 353° 32.6 36
* red - uhf KPXN-DT 38.1 i SAN BERNARDINO CA 353° 31.8 38
* red - uhf KTBN-DT 23.1 TBN SANTA ANA CA 353° 32.5 23
* red - uhf KCOP-DT 13.1 UPN LOS ANGELES CA 352° 32.7 66
* red - uhf KCET-DT 28.1 PBS LOS ANGELES CA 353° 32.5 59
* red - uhf KJLA-DT 57.1 IND VENTURA CA 352° 32.6 49
* red - uhf KFTR-DT 46.1 TFA ONTARIO CA 12-05 352° 32.6 29
* red - uhf KABC-DT 7.1 ABC LOS ANGELES CA 352° 32.7 53
* blue - uhf KSCI-DT 18.1 IND LONG BEACH CA 353° 31.8 61
* blue - uhf KWHY-DT 22.1 IND LOS ANGELES CA 352° 32.6 42

mgtr

09-30-05, 04:49 PM

mvita-
I cut a length of 300 ohm twinlead to (I think) 28 inches (I am not in Fla right now), twisted the ends together, and put a 300 to 75 ohm balun in the middle of one lead. I cut a piece of 1" PVC pipe about 30" long, and then taped the twinlead to the pipe. For aesthetics (and to help hide it), I sprayed the pipe, twinlead, and tape grey. I then took the SS apart and screwed up through the plastic housing into the PVC pipe, thus mounting the pipe on top of the SS, crossways (in other words, the pipe is in the same plane as the housing). I took a short length of RG-6 and connected the balun out to the VHF in on the 7777, and opened up the 7777 and changed the setting from combine to separate.
It almost takes longer to write this up than to do it. I cannot take a picture (which would help enormously) because I am in SC. However, if you do a search in this topic for mgtr, you should turn up a response to me, when I had the same question as you, which included a picture of another fellows rig.
The upshot of the above, by the way, is i get WESH just fine, even though I am driving about 75 feet of RG-6.

Good luck!

holl_ands

09-30-05, 05:35 PM

sregener,
I too was surprised by the 4248 data. In fact, I went back to the raw data twice to make certain that I had not transposed the raw data between antennas. From past experience, I would have expected it to have a mid-range performance curve. Next month, when I check some of these antennas out at edge of the DTV signal, we'll see if the peck'n order changes.

When you see the 3671 close up and you just focus on the UHF portion, there is a lot of UHF antenna there. The only antenna I ever installed that matched the 3671's performance in the field was the biggest Quantum series antenna CM made. (1161B?)

Bob Chase

In your 3/28/05 post, I was surprised to see CM4221 4-Bay Bowtie had higher outdoor gain than any other antenna then tested,
except at lower frequencies, where it was squeezed out by the CM-4228 8-Bay Bowtie:
http://www.avsforum.com/avs-vb/showthread.php?p=5399471#post5399471

Go Figure....

Could I also suggest testing the Silver Sensor (and/or Terk HDTVi) and perhaps the W-G SS-3000 SharpShooter....
But since these aren't fringe reception antennas, perhaps an indoor test could be a future undertaking.

PhracturedBlue

09-30-05, 11:14 PM

I originally posted some of this info in the Portland, OR thread, but perhaps I can get more info here. I have what appears to be a CM 3016 on my roof (from previous owners) which is a medium-range uhf/vhf. I recently got an HDTV capture card, and went out to aim the antenna to get better (any) reception. I live about 11 miles from the big transmitter array (where all the majors transmit from), but that is on top of a ridge, and I live near the bottom of the same mountain ridge 11 miles north (so there is basically no way to get a line of sight). antennaweb says all of the channels are blue. The channel I am most interested in is our PBS affiliate, which is on channel 27. Anyhow, after lots of playing around, I found that I could get about 15db SNR on PBS with the antenna pointed right at the transmitter (not good enough for a lock), but I can get about 18db by pointing the antenna nearly 180-degrees away (it's actually more like 160-degrees), which is enough for a lock, but with frequent dropouts. Since this antenna has a corner reflector, and I can tell it is very directional, I am assuming I'm picking up a reflection off the side of the mountain. By the way, all of the channels come in better when tuned this way (which isn't too surprising since they all transmit from the same point).
I figured I probably need a bigger antenna and/or a pre-amp. Since the most important channel for me is 27, and yagis really perform well at higher frequencies, I was thinking of getting a CM 4228 and a 7775 pre-amp. But I am worried about multipath as I seem to have quite a strong reflection. So now I'm wondering if I should get a bigger UHF-only yagi. Maybe a CM4248 or a 91XG instead (probably with the pre-amp as well). Is one of these more likley to work well for me than the other? I'd certainly prefer a yagi, as they are lighter, less ugly, and have less wind-resistance, but I'll get whatever is likely to give me the best reception.

holl_ands

10-01-05, 04:30 AM

Can you be more specific on your location, give or take a few hundred yards?
Google-Earth is fun and easy to use for this purpose. Use Tilt controls to see elevation.

Yep, sounds like you are picking up a backscatter signal after it is reflected off a (nearby?) hill.

Every time I hear about someone sitting "under" the broadcast towers, it seems to be anybody's guess as to
whether you are starved for signal because you are "under" their very narrow antenna pattern (like a pancake).

On the other hand, it is more likely that you are saturated with signals coming in from
several different directions and multipath is your biggest problem.
Unfortunately, the SNR display only tells you how "good" the signal is,
and not how strong it is.

Two things that will combat multipath are:
1) try different antenna locations until you find a "hot" spot.
2) go with the CM-4228, because multipath nulls will affect some of the bow-tie elements and not others.
It also has higher gain, higher F/B ratio and narrower beamwidth to reject multipath.
It also costs less than a big Yagi.

For the same sort of reasons, either
1) the Preamp will help because you have low signal strength, or
2) it will make things worse because it is overloaded, or
3) it will be just what you need......
PS: The lower gain Winegard Preamps are better suited than CM7775,
since they can tolerate much higher signals before they overload.

Sorry if this sounds like it is just soooooo useful.....

greywolf

10-01-05, 08:50 AM

Use Tilt controls to see elevation.And in cases like this, tilting the antenna itself can sometimes help. Just as rotation helps asimuth determination, tilt can help elevation determination in close in situations where there is a large elevation difference between transmitter and receiver.

deconvolver

10-01-05, 09:06 AM

...
Two things that will combat multipath are:
1) try different antenna locations until you find a "hot" spot.
2) go with the CM-4228, because multipath nulls will affect some of the bow-tie elements and not others.
It also has higher gain, higher F/B ratio and narrower beamwidth to reject multipath.
It also costs less than a big Yagi.
...
The Winegard PR-9032 is a big Yagi that costs much less and should have less wind load than a CM 4228. I agree that the 4228 will probably work better in this situation but the PR-9032 is cheap enough to try to see if it is good enough.

sregener

10-01-05, 09:17 AM

Whats does this mean?

* yellow - uhf KOCE-DT 50.1 PBS HUNTINGTON BEACH CA 353° 32.6 48
* green - uhf KDOC-DT 56.1 IND ANAHEIM CA 352° 32.7 32
* lt green - uhf KLCS-DT 58.1 PBS LOS ANGELES CA 353° 32.5 41
* red - uhf KRCA-DT 62.1 IND RIVERSIDE CA 353° 31.8 68
* blue - uhf KSCI-DT 18.1 IND LONG BEACH CA 353° 31.8 61

Extras removed for clarity.

Yellow, green, lt green, red, and blue are codings of antennas - the further down that list you go, the larger the antenna you theoretically will need to get a good signal. Most suburban antennas will do fine at blue.

The UHF tells you that the signal is on the UHF band, traditionally channels 14-67.

The K***-DT tells you the call letters of each station.

The *.1 tells you the virtual channel number (i.e., the traditional analog channel you know as, for instance channel 50.)

The PBS/IND/ABC/Fox/Etc. tells you the network affiliation (IND = independent) of each station.

The city tells you the city of license for each station.

The degree rating tells you what compass direction the station's transmitter is from the address you provided.

The next number is the distance in miles to the transmitter.

The final number is the actual channel slot the digital transmitter is broadcasting on. If you're having trouble tuning a particular station, tuning to this number (e.g. 48-1) instead of the virtual number may help to clear things up.

You don't say if you're looking for an antenna recommendation, but I'd say you're highly likely to have success with a Channel Master 4221 for the list you provided.

PhracturedBlue

10-01-05, 11:01 AM

Can you be more specific on your location, give or take a few hundred yards?
Google-Earth is fun and easy to use for this purpose. Use Tilt controls to see elevation.

Sure. I am near here:
45°39'36.20"N
122°52'57.71"W
Elev 230 ft
(I don't think placing my coordinates on a message board is really a great idea, so that is just a rough estimate of where I am. If you want more precise coordinates, you can PM me).

The antenna is currently mounted on the roof, but moving it might not be that easy (and would make mounting a lot more difficult)

The Sylvan antenna group is here:
45°30'57.65"N
122°43'59.80"W
Elev 1056 ft
(That is ground level, I'm not sure how tall they are.

The Skyline group is (I think) here:
45°31'20.87"N
122°44'49.29"W
Elev 1128ft

(Note that KOPB (the channel I am most interested in) transmits from the Skyline site, but I'm not 100% sure i chose the right one (there are 3 transmit sites within a half-mile of each other, so it shouldn't really make much difference)

I played with the tilt controls in Google Earth, but didn't find them useful for determining obstructions. I really need a topo-map or equivalent for that.
Unfortunately, the SNR display only tells you how "good" the signal is, and not how strong it is.
Well, i have 'signal strength' info, but I'm working in linux here, and the numbers don't have any absolute meaning, just relative to one another (I get a stronger signal by ~10% if I aim at the antenna, vs where I am aimed now, but the snr is lower, and, as I said, I can't get a lock
Sorry if this sounds like it is just soooooo useful.....
It was actually very helpful, thanks.

Hoppy

10-01-05, 03:10 PM

just got HDTV reinstalled. I am using DirecTV and now I'm trying to get some OTA signals with a small internal set-top type of antenna. I live in Hattiesburg, MS, and have the following signals/distances

WDAM-DT (NBC) 10.7 mi
WDAM (NBC) 10.7 mi
WHLT (CBS) 9.9 mi
W47BP (PBS) 2.4 mi
WLOX (ABC) 44 mi
W45AA (PBS) 28 mi
WXXV (FOX) 43 mi

There are others in my antennaweb.org list of stations, but these are the mail ones.

I bought a TERK HD antenna from BB just to try and got exactly 1 signal, the local NBC (WDAM-DT). Nothing else.

So I am interested in seeing what other indoor antennas are thought to be good for this purpose. The Zenith ZHDTV1 HDTV-UHF antenna is very cheap and gets raves on Amazon and various other places, so I ordered one of those thinking it could not be worse, or could only be a little worse, than the Terk and it was $25 cheaper. But what other alternatives do I have? Is that TERK that clips onto the DirecTV dish agood antenna (OK, it's external, but I'm thinking outside the box now).

Anyway, any help or advice, suggestions, testimonials, humorous asides, etc. much welcomed.

bernieoc

10-01-05, 04:34 PM

governorb

10-01-05, 06:02 PM

Thank you Sreneger-

One more question. If I live in a 6 floor condo am I better off with indoor antenna or should I put an outdoor one on my balcony? I have a large balcony which faces south, just like DTV and dish which I am both able to get.

Is this a good indoor one

http://www.radioshack.com/product.asp?catalog%5Fname=CTLG&category%5Fname=&product%5Fid=15%2D1880

Extras removed for clarity.

Yellow, green, lt green, red, and blue are codings of antennas - the further down that list you go, the larger the antenna you theoretically will need to get a good signal. Most suburban antennas will do fine at blue.

The UHF tells you that the signal is on the UHF band, traditionally channels 14-67.

The K***-DT tells you the call letters of each station.

The *.1 tells you the virtual channel number (i.e., the traditional analog channel you know as, for instance channel 50.)

The PBS/IND/ABC/Fox/Etc. tells you the network affiliation (IND = independent) of each station.

The city tells you the city of license for each station.

The degree rating tells you what compass direction the station's transmitter is from the address you provided.

The next number is the distance in miles to the transmitter.

The final number is the actual channel slot the digital transmitter is broadcasting on. If you're having trouble tuning a particular station, tuning to this number (e.g. 48-1) instead of the virtual number may help to clear things up.

You don't say if you're looking for an antenna recommendation, but I'd say you're highly likely to have success with a Channel Master 4221 for the list you provided.

greywolf

10-01-05, 08:07 PM

One more grounding question.
My antenna, dish and coax grounding rod is 60' from main house entry ground. I have a good supply of 14-3 romex. can I use this ( all 4 wires tied together as one - on each end) as an adaquate tie in to my house ground? Also as my ground from antenna and coax to new ground? Are 3 insulated +1 bare copper wire tied togrther equal to required code wire?Four 14ga wires have slightly more resistance than one 8ga wire. That isn't good enough for the required 6ga bond wire for the rod to the main house ground. It is good enough for the antenna or dish mast to the main house ground as far as resistance is concerned. Always check your local codes though.

adriana

10-01-05, 11:58 PM

holl_ands

10-02-05, 07:10 AM

I have what appears to be a CM 3016 on my roof which is a medium-range uhf/vhf. I live about 11 miles from the big transmitter array (where all the majors transmit from), but that is on top of a ridge, and I live near the bottom of the same mountain ridge 11 miles north (so there is basically no way to get a line of sight).
antennaweb says all of the channels are blue.
The channel I am most interested in is our PBS affiliate, which is on channel 27.
I found that I could get about 15db SNR on PBS with the antenna pointed right at the transmitter (not good enough for a lock), but I can get about 18db by pointing the antenna 160-degrees away, which is enough for a lock, but with frequent dropouts.
I am assuming I'm picking up a reflection off the side of the mountain.
By the way, all of the channels come in better when tuned this way (which isn't too surprising since they all transmit from the same point).
I figured I probably need a bigger antenna and/or a pre-amp. Since the most important channel for me is 27, and yagis really perform well at higher frequencies, I was thinking of getting a CM 4228 and a 7775 pre-amp.
But I am worried about multipath as I seem to have quite a strong reflection.
So now I'm wondering if I should get a bigger UHF-only yagi.
Maybe a CM4248 or a 91XG instead (probably with the pre-amp as well). Is one of these more likley to work well for me than the other? I'd certainly prefer a yagi, as they are lighter, less ugly, and have less wind-resistance, but I'll get whatever is likely to give me the best reception.

I used the (FREE) RADIO MOBILE (RM) propagation prediction program to calculate the Irregular Terrain PATH LOSS.
PATH LOSS is the ONLY parameter from RM used in my DTV PATH LOSS CALC spread sheet,
along with best guesses for your site specific parameters, so tweak away.
See fol. for spec summaries for various Antennas, Preamps, Baluns and Cable choices:
http://hdtv.forsandiego.com/messages/1/2846.html?1126998999
A detailed explanation of RM and the spread sheet is also included.
And it's fairly easy to download and use RM, including a helpful Yahoo User Group.

==================================================
Below is a Topo Map and Radio Link Profile for the coordinates you provided.
You are not "below" the broadcast antenna pattern as first feared.
The KOBP-DT tower is on the left and diffracts along the ridgeline to your location.
It shows one principal peak in the way, followed by a minor hill just South of you.
Note that the signal is skirting along the ground for the last several miles,
so, if you can, raising your antenna will help.

Although you are only 11.6 miles away there is over 36 dB of Diffraction Loss in excess of Line-Of-Sight, per RM.
CM3016 without a Preamp was calculated to be very marginal.
CM4228 (or most any other hi-gain antenna) greatly improved the available Fade Margin.

I also calculated improvement with W-G AP-4700 and CM-7777 Preamps for both antenna choices.
A high-gain antenna (like the CM4228) without a Preamp was better than the CM3016 with a Preamp.
And a high-gain antenna with a Preamp was better still.

An overload calculation was included for analog KNMT, with 2590 kW ERP.
There is a new station planned with 5000 kW ERP, but they probably are not on the air yet. If so, add another 3 dB.

The direct path signal was safely 30 db below AP-4700 spec overload point
and 23 dB below for CM-7777. This will ensure maximum sensitivity.
However, you are no doubt getting backscatter reflections from the bowl shaped hills 1 or 2 miles NW of you.
In order to play it safe, I would go with the higher overload AP-4700.
It only amplifies UHF and passes thru VHF with minimal loss.

Note that the CM-7777 is high gain Preamp for both UHF and VHF,
which will cause overload problems for VHF at your location.
And the CM-7775 is UHF only and does not pass the VHF signals.

==================================================
On Google-Earth, your coordinates were between Morgan Rd and Logie Trail Rd, near a power line, away from nearby hills and valleys.
When I did a "best fit" of your location for Antennaweb,
KOPB-DT and several other DTV stations were "yellow".
I had to move the location either more downhill or south, closer to the hill before I saw Red/Blue readings.
If this is the case, RM calculated another 3-6 dB of Diffraction Loss.
If you look at the profile, the worst location would be further South, along Cornelius Pass Rd.

=====================================================
The above runs were using the on-line SRTM-3 Topographic database that is autoloaded as RM needs it.
The higher resolution SRTM-1 database needs to be manually downloaded for your area before it can be used.

=====================================================
Every once in a while unusual problems in particular locations grab my interest.
In order to gather information on how well RADIO MOBILE predicts DTV reception relative to antennaweb.org,
I would appreciate hearing from you on how well various stations are received.

I hope this little exercise inspires others to give it a twirl....

holl_ands

10-02-05, 07:54 AM

hey guys i saw this site over google and i really need help on finding the best antenna. i live in los angeles and only 15 miles away from the transmitter tower and antennatv said that i need a red mid directonal tv antenna. i search around and i saw ZENITH Silver Sensor as one of the best indoor antenna but that only accepts HDTV AND uhf. but what is vhf and uhf? well currently my tv does not have HDTV build in and i was wondering if i could still use that antenna to pickup channel such as 4,5,7,9,11,13. i do not have cable or direct tv or anything and im not planning on getting those. i would just like to get clear and good reception on those regular channels. im pretty sure i dont have UHF so what would be the best VHF Antenna?
how about the philips silver sensor which accepts HDTV, digital DTV, VHF, UHF, and FM.
We need more specific information on your location, like closest cross streets dude.

Also, what kind of antenna connections do you have on you TV?
Do you have just a single twist-on type connector or do you have one or two pairs of screws labelled "VHF" and "UHF"?

Silver Sensor is a UHF antenna (channel 14 and up) and isn't much of a VHF antenna (channel 13 and below),
but then you shouldn't need much....Rabbit Ears will work about as well or better.
If that isn't enough, then a big outdoor antenna may be next.

There is no difference between the last 30+ years of TV antennas and those currently labeled "for HDTV".

deconvolver

10-02-05, 08:42 AM

hey guys i saw this site over google and i really need help on finding the best antenna. i live in los angeles and only 15 miles away from the transmitter tower and antennatv said that i need a red mid directonal tv antenna. i search around and i saw ZENITH Silver Sensor as one of the best indoor antenna but that only accepts HDTV AND uhf. but what is vhf and uhf? well currently my tv does not have HDTV build in and i was wondering if i could still use that antenna to pickup channel such as 4,5,7,9,11,13. i do not have cable or direct tv or anything and im not planning on getting those. i would just like to get clear and good reception on those regular channels. im pretty sure i dont have UHF so what would be the best VHF Antenna?
how about the philips silver sensor which accepts HDTV, digital DTV, VHF, UHF, and FM.
One way to get an excellent picture is to get a digital set-top over the air receiver even if you don't have an HDTV. Radioshack had an Accurian model on clearence for less than $100 (but they are getting scarce- call your local stores before trying them), check the HDTV hardware forum for a thread with more info on it. I think Walmart also has a receiver that is not too expensive. You will get the best results with them if your TV can use an s-video (or better yet the three cable component) type connection. Most of the digital signals will be on UHF even though the station still calls itself by its old analog channel number. If you go to www.antennaweb.org and type in your address then it will show you the channels available in your area. If the last column labelled frequency assignment shows a channel of 14 or higher then a station is broadcasted on UHF. The antennaweb prediction is pessimistic in its digital station predictions though; I get all the major networks digitally from Hartford/New Haven with good outdoor antennas/pre-amp yet antennaweb predicts that I will get none.

PhracturedBlue

10-02-05, 12:34 PM

I used the (FREE) RADIO MOBILE (RM) propagation prediction program to calculate the Irregular Terrain PATH LOSS.
This is wonderful information. I downloaded RM, and got maps for my area, however, I am not sure how you got the information about the transmitters (power, mast-height, etc). Is this information available online?
It is a cool program, and I'd love to be able to play with it. some more.

In any case, thanks for the data, I really appreciate the help and recomendations. I've found it amazing how helpful people are on this board.

Edit: Okay, so I found antenna info here:
http://www.fcc.gov/fcc-bin/tvq?list=0&facid=50589 which seems to state the the Digital broadcast has an ERP of 753kW (it looks like you used 380kW, which appears to be the analog transmission)

I plugged the numbers into RL (I didn't know how to get the antenna gains, so I just used what you used), and got this:

Am I doing this right?

When I plugged in the actual path loss for my coordinates (140 vs 149), and the Tx power of 753 vs 318, I see that the CM3016 should be giving me a Fade Margin of 27.2db (I'm not 10% sure what this is, but it is apparently the summary result from your spreadsheet). This would seem to say that the 3016 should be 'good' even without a pre-amp (which it certanly is not). So I'm not sure what is going on here.

adriana

10-02-05, 02:57 PM

im planning to watch only channel 2-13 but i really want it to be clear. i live in an 2 story apt. and im on the first floor. i check on back of my tv and it shows UHF/VHF connector. with the antenna right now i get ghosting which is really annoying. its just some cheap 10 dollar antenna that my parent bought. it looks like a little dish in the middle shape as a circle with two antenna sticks on each side.

deconvolver- i do have s video but there its only for IN VIDEO 1 and what is the three cable component? sorry im really new

thank you all for helping

deconvolver

10-02-05, 04:14 PM

deconvolver- i do have s video but there its only for IN VIDEO 1 and what is the three cable component? sorry im really new

thank you all for helping
Three cable component is what the newest TVs (especially high definition monitors) and DVD players have; you don't need it for a set-top box because the s-video connection would work great. If you are already using all your video inputs to connect something else like a DVD player to your TV then you would need a way to switch between what is on video-1 and any external set-top box that you add. I have a surround sound A/V amplifier that can do that switching and there also exist little mechanical switches where you push a button to select which item you want to go to video-1. If you had a digital set top box then it should receive all your channels with a UHF antenna like the silver sensor. You would connect the silver sensor to the digital TV receiver box then an s-video cable and stereo cables between the box and TV video-1 input. You would then do an autoscan on the box with the antenna pointed in the direction of the station towers. With the TV set to video-1 you would change channels with the remote that comes with the box. The picture that you end up with will be better than is possible using the antenna input on the TV itself; especially during prime time when the digital channel is high-definition.

The station towers are located 28 degrees on a compass from your location. One way to find out how to point the silver sensor for the digital stations is to temporarily connect it to the UHF antenna input on the TV. Point the antenna until you get a UHF station from LA like KLCS channel 58 in well. Then move the antenna connection to the set-top box and do the autoscan.

Here is a link to the Radio-Shack set-top box thread (if you call around you might find a local Radio-Shack that still has one of these):
http://www.avsforum.com/avs-vb/showthread.php?p=6285356&&#post6285356

With an antenna connected directly to the TV input you would be getting the analog channel and there is no way to make a good directional antenna for channels 2 to 6 that is not huge. The technical reason is that the size of the radio waves for channels 2 through 6 are big but those stations are transmitting digitally on UHF channels and UHF waves are small so the antenna can be small.

holl_ands

10-02-05, 07:03 PM

This is wonderful information. I downloaded RM, and got maps for my area, however, I am not sure how you got the information about the transmitters (power, mast-height, etc). Is this information available online?
It is a cool program, and I'd love to be able to play with it. some more.

In any case, thanks for the data, I really appreciate the help and recomendations. I've found it amazing how helpful people are on this board.

Edit: Okay, so I found antenna info here:
http://www.fcc.gov/fcc-bin/tvq?list=0&facid=50589 which seems to state the the Digital broadcast has an ERP of 753kW (it looks like you used 380kW, which appears to be the analog transmission)

I plugged the numbers into RL (I didn't know how to get the antenna gains, so I just used what you used), and got this:

Am I doing this right?

When I plugged in the actual path loss for my coordinates (140 vs 149), and the Tx power of 753 vs 318, I see that the CM3016 should be giving me a Fade Margin of 27.2db (I'm not 10% sure what this is, but it is apparently the summary result from your spreadsheet). This would seem to say that the 3016 should be 'good' even without a pre-amp (which it certanly is not). So I'm not sure what is going on here.

Wow, you sure came up the RM learning curve at rocket speed!!!
Sounds like you are making great progress and just need to absorb it all in now.

The path profile looks slightly different, so I would guess that you are using your real, more accurate position.
Even with this change, you get 148.2 dB vs my 149.0 dB for PATH LOSS.
This is very close agreement, given that it varies a couple dB depending on the chosen range scale and specific location.

In the near future I'll post my RM settings for LA and San Diego as an example,
but it looks like you got most things right (e.g. horizontal polarization),
and no doubt have questions re some of the more obscure settings.

For improved accuracy you should download SRTM-1 to a folder and set RM up to use internal database,
rather than reloading lower rez SRTM-3 everytime you change range scales.

DTV_FADE_MARGIN_CALC_EXAMPLE says how to find info to plug into the spread sheet calculator.
Clutter Loss, Loss due to attic/indoor antenna location and loss of sensitivity due to antenna VSWR are on-going subjects.

DTV_ANTENNAS summarizes spec sheet, NEC Simulation and actual measurements for dozens of antennas.
The fol. thread also has a lot of useful antenna and other hardware info:
http://www.avsforum.com/avs-vb/showthread.php?t=546066

Unfortunately, RM doesn't have very much site specific tailoring (or maybe I haven't found it yet, or it's just too hard).
Such as entering antenna gain vs channel frequency. So I just entered an average value.
Hence the need for the spread sheet calculator.

=====================================================
You should always bear in mind that RADIO MOBILE, like all of the Longley-Rice Irregular Terrain Models,
are based on statistical averages gathered from thousands of (ill defined) locations around the world.
The F(50,50) selection that I normally use (as per FCC OET-69) represents results
for 50 percent of locations, 50 percent of the time.
This means half the locations will have worse performance.
Or a particular location will have worse performance half the time.
Some say the Longley-Rice results are +/- 10 dB.
Hence the need to have an adequate Fade Margin.

I'm still collecting information on how much Fade Margin is "adequate".
I'm sure that 15 dB is too small and 30-40 dB should be enough.
In between, predicting actual performance depends a lot on those pesky assumptions....

But at least we can now do some "what if" exercises...

Such as rerunning RM with an F(50,90) setting, such as is stipulated for determining
SHVERA eligibility for distant network service.
Or even F(90,90)....so called "guaranteed" service reliability...
In which case the Fade Margin requirement would probably decrease.

======================================================
The FCC database has two entries for KOPB-DT (CH27).

1. The Special Temporary Authority (STA) entry says 381 kW,
[which was very close to an existing SYSTEM entry for "NBC KNBC-DT in LA"].
[My choices for receive antenna gain were also limited to existing entries, since I've used up all the SYSTEM entries.]

2. The Modification of Construction Permit (Mod CP) entry says that they plan to increase power to 753 kW.
The first entry did not stipulate an antenna or antenna pattern,
whereas the second lists a Dielectric model number that is presumably non-directional.

I have found it to be extremely difficult to determine when these planned improvements are actually on-the-air.
So I've assumed the worst case and used the lower power level.

======================================================
Note that although the Preamp input was not overloaded, the amplified signal level going to the HDTV was at a very high level.
RF Splitters and/or a Variable RF Attenuator (e.g. R-S 15-678) should be used on the input to the HDTV and tweaked
to lower the strongest signals (i.e. analog KNMT) so that they do not affect reception of other channels.
I would expect most HDTV's will start having intermod problems as the strongest signal approaches the -10 to 0 dBm region.

newsposter

10-02-05, 07:37 PM

hey!! thanks for the reply. well here my address so you can see what it says in antennaweb.

LOS ANGELES, CA 90012

Maybe it's the paranoid in me but I'd recommend deleting your address in a public posting forum :) Unless you already gave out a fake one, which in that case, excellent job!

adriana

10-02-05, 07:38 PM

adriana

10-02-05, 07:40 PM

ok i just deleted it

PhracturedBlue

10-02-05, 07:58 PM

The path profile looks slightly different, so I would guess that you are using your real, more accurate position.
Even with this change, you get 148.2 dB vs my 149.0 dB for PATH LOSS.
This is very close agreement, given that it varies a couple dB depending on the chosen range scale and specific location.

Actually, I think I just wasn't clear. The pic from my last post was at the same location I gave you (to show I could get similar results), though I did use the 1m geo-data (wihch might explain the difference). i also may have used a different tower location than you did. In any case, my number was very close to yours, so I figure I had everything set pretty much the same.

I've included a pic from my actual location. As you can see the path-loss is 140 now, at F(50,50). When I go to F(90,90) it shows 152dB. And thanks for explaining how to use those settings. I wasn't sure what I was supposed to do with them.

Also, I'm not sure what impact trees will have on the results. The land between the antenna and myself is almost entirely forested, mostly with large connifers.

Anyhow, I think I have enough info, and I'll just buy a 4228 and pre-amp (not sure which one yet), and see how it goes. I'll report back after I've done some real testing. Again, thanks for all the info. This has been a great learning experience.

Heuristix

10-02-05, 10:51 PM

A few questions from a newbie begining to look into HD.
My antennaweb data is as follows

yellow - uhf WTVE 51.1 IND READING 333° 23.4 miles 25
red - uhf WPVI 6.1 ABC PHILA 111° 9.7 miles 64
red - uhf KYW 3.1 CBS PHILA 111° 9.7 miles 26
blue - uhf WTXF 29.1 FOX PHILA 104° 9.8 miles 42
blue - uhf WPPX 61.1 i WILM 111° 10.1 miles 31
blue - uhf WPSG 57.1 UPN PHILA 111° 10.1 miles 32
blue - uhf WPHL 17.1 WB PHILA 111° 10.1 miles 54
blue - uhf WYBE 34.1 PBS PHILA 111° 10.1 miles 34
violet - uhf WLVT 39.3 PBS ALLENTWN 10° 34.5 miles 62
violet - uhf WHYY 12.1 PBS WILMTN 111° 9.9 miles 55
violet - vhf WBPH 59.1 FMN BETHLHM 10° 34.5 miles 9

1. Why do channels 6 and 3 show up as UHF rather than VHF? Can I use an UHF only antenna and try to receive these channels?

2. What does the last column (frequency assignment) refer to? It does not seem to follow the same rank order as the channel number. For example channel 6 has a frequency assignment of 64 (MHz?) whereas channel 39 has a frequency assignment 62 and channel 29 has 42. Are channel numbers not sequential with respect to frequency?

3. Luckily, it seems like the stations I would like to recieve are all at 111 degrees or the very close 104 degrees; so I could get away with a fixed directional antenna. However my house is in a wooded area on a slope with about a 10 degree incline and the antenna would have to point up the slope; i.e. broadcast towers are on the other side of the hill. Do I have a prayer? Based on my fairly meager understanding of the article by Peter H. Putman "Heavy Metal, Part I at svconline, I was going to try the Radio Shack VU-90 XR since it does not seem too bad, and is easily returned if it does not work. Or should I go for one of the more highly recommended antennas on these forums e.g. CM 4221 to give it my best shot?

Any thoughts appreciated.

bobchase

10-02-05, 11:22 PM

Heuristix,
The last column is the TV channel that the digital signal is actually on. Hence, ch 3 & ch 6 show up as UHF channels 26 & 64 respectively on the list.

Your are very close to the towers, so over the hill reception is not out of the question. Try to find a Channel Master 4228 at Lowes, Fry's, Home Depot, or some other store. It has good gain and good multipath rejection (eliminates ghosts) and you'll need both. It should cost less also.

If you want to or need to get both analog and digital signals from your antenna, as the VU90 can do for you, then look for a Channel Master 3016 or a Winegard HD7210 antenna. They both perform very well for homeowners in your situation.

Good Luck,

Bob Chase

holl_ands

10-03-05, 02:39 AM

Actually, I think I just wasn't clear. The pic from my last post was at the same location I gave you (to show I could get similar results), though I did use the 1m geo-data (wihch might explain the difference). i also may have used a different tower location than you did. In any case, my number was very close to yours, so I figure I had everything set pretty much the same.

I've included a pic from my actual location. As you can see the path-loss is 140 now, at F(50,50). When I go to F(90,90) it shows 152dB. And thanks for explaining how to use those settings. I wasn't sure what I was supposed to do with them.

Also, I'm not sure what impact trees will have on the results. The land between the antenna and myself is almost entirely forested, mostly with large connifers.

Anyhow, I think I have enough info, and I'll just buy a 4228 and pre-amp (not sure which one yet), and see how it goes. I'll report back after I've done some real testing. Again, thanks for all the info. This has been a great learning experience.

Good news, your actual location improved PATH LOSS by 10 dB, you must be closer to a ridge.
Which means your earlier antennaweb.org results probably correspond to a slightly worse location.
I've never had much confidence in antennaweb.org being very accurate with respect to terrain location.
I think that it is using either 1 km or 2 km square tiles..which is way too granular.

And you can generally see the importance of having an "adequate" Fade Margin.

The signal path just grazes the ridgeline, being in the trees a lot.
Conifers are the worst UHF absorbers, but it's only a relatively small fraction of the total path.

If it's any comfort, the underlying Irregular Terrain statistics were taken for a large number of locations,
so many of them had forested terrain like yours. So, it's already included in the model.

JRod0802

10-03-05, 03:11 AM

I recently bought an HDTV and I want to see what kind of HD channels I can receive OTA. I have been reading a lot on these forums, and i have a specific question. I live fairly far away from any towers. I approximately live at 42 degrees 18'55.90" N, 72 degrees 40'04.09". Roughly On Burts Pit Road between florence rd. and clement st. Northampton, MA 01062. Most of my signals come from Springfield or Hartford. (Most of these in the red or blue color at antennaweb) I was wondering if i would be able to mount a SS-1000 on my roof with a CM-7777 preamp and have a hope to get these signals. I also was wondering if the SS-2000 (built in pre-amp) would work just as well as the SS-1000 with the CM-7777 because it costs less that way.
Thanks again for making such a great forum. I have learned a lot in the last two days (back when i didn't even know what uhf/vhf meant) and would appreciate any information. Thanks.

holl_ands

10-03-05, 05:25 AM

so to my understanding is that i need to get a set-top box(Accurian HTS 6000??) and an antenna(silver senor). my row for Video-1 is taking up by the dvd player but i can easily take that out. so i would buy the set-top box and plug those cable from the box to to the s-video, video, L audio, and R audio.(all in video 1 row). then do a autoscan on the box with the antenna pointed in the direction of the station towers at 28 degrees.
if i do that then channels 2,4,5,7,9,11,13 will be clear? would there still be ghosting?
and if that won't work do you think radio shack will let me return those things? thank you this helped ALOT!! now i gotta go find the hts 6000 those seem to be sold out. oh i read about talking about STB? what does that mean

Since you can't get good, multipath free VHF signals in your location and
mounting a big outdoor antenna is probably not a viable option,
leaping forward with a Digital TV receiver should overcome those multipath blues.
In a couple years, this will be the ONLY way to receive free on-air signals
as the existing analog TV system is phased out.....and it might be even sooner.

The Radio Shack HTS-6000 is the least expensive High Definition Digital TV Receiver currently available:
http://www.radioshack.com/product.asp?catalog%5Fname=CTLG&category%5Fname=CTLG%5F003%5F006%5F000%5F000&product%5Fid=16%2D3499#
http://support.radioshack.com/manuals/ome16-3499.pdf
These are also called an STB (Set Top Box), because....uhhh, some people set them on top of their TV.

Sounds like you understand how to connect it to your TV.
You can display SD (Standard Definition) digital TV signals on those televisions equipped
with either an S-Video or Composite Video (Yellow) connector, plus Red/White for Stereo sound.
[For those people who don't have either of these, an inexpensive converter, like for a game console,
can be used to connect directly to the antenna input on ANY TV.]

In the future you could connect the HTS-6000 to a High Definition TV via Component Video cables
(Red/Green/Blue) and experience the full benefit of this new technology.

The HTS-6000 also has Optical and Coax Digital Audio outputs, so you can
connect one or the other to a Surround Sound System.

===================================================
You can check whether a store has a unit in stock at the R-S link above.
Unfortunately, the search engine appears to be limited to not much more than a single zipcode area.
I didn't have the patience to try EVERY zipcode in LA, but did find that the (92605 zipcode)
store in Huntington Beach (714-846-0158) has units in stock.
They also have them in stock down here in San Diego and Del Mar.
Best bet is to have the store do a search on their computer, rather than trying every zipcode in LA.

===================================================
You can also add an inexpensive Video Switch to select between the STB and your DVD:
http://www.radioshack.com/product.asp?catalog%5Fname=CTLG&category%5Fname=CTLG%5F003%5F010%5F011%5F000&product%5Fid=15%2D1982
http://www.radioshack.com/images/ProductCatalog/Manuals/OME15-1982.pdf
or the following (no manual posted, so ask clerk if it is suitable):
http://www.radioshack.com/product.asp?catalog%5Fname=CTLG&category%5Fname=CTLG%5F003%5F010%5F011%5F000&product%5Fid=15%2D1217
You might find one that looks better at WalMart, CircuitCity, BestBuy and elsewhere.

===================================================
A comment about Aspect Ratio Controls:
On old (analog) TVs, you will frequently see a movie in LETTERBOX format.
There are black stripes at the top and bottom.

When watching Digital TV on a old analog TV, like you have, you will continue
to see normal full 4:3 screen displays and LETTERBOX displays for many programs.
However, when High Definition (HD) programs are carried (mostly primetime now),
there are more options available.

The primary HD sub-channel is in 16:9 widescreen format in order to fit those new and wider HDTVs.
When the signal comes out the S-Video or Video port, there are NORMAL, WIDE and ZOOM
aspect controls available to shrink or expand the picture size to better fit your 4:3 TV, give or take those pesky black stripes.
Several stations also carry both HD and SD sub-channels with the same program,
so you can select SD to best fit your 4:3 TV.

================================================
Always ask the clerk to make sure, but Radio Shack normally has 30 day return policy.

adriana

10-03-05, 09:05 AM

THANkks!!!holl_ands. gosh this fourm is like the best one out of all the other forums that talks about hdtv and all those stuff!! i love this forum!!!!!!

sregener

10-03-05, 09:06 AM

One more question. If I live in a 6 floor condo am I better off with indoor antenna or should I put an outdoor one on my balcony? I have a large balcony which faces south, just like DTV and dish which I am both able to get.

Is this a good indoor one

http://www.radioshack.com/product.asp?catalog%5Fname=CTLG&category%5Fname=&product%5Fid=15%2D1880

It's hard to say for sure, since your stations are north. If you can pick up a reflection from a nearby building, outdoors may be better. Otherwise, you'll just be adding one more wall that the signal has to travel through in order to reach your antenna.

There is no better indoor antenna than the Zenith Silver Sensor. The Radio Shack antenna you list costs more, and performs much worse. You want to avoid anything that says "amplified" on it for an indoor installation.

deconvolver

10-03-05, 10:28 AM

K Rock XP

10-03-05, 11:34 AM

sregener

10-03-05, 12:35 PM

Also is there a nice cost effective ant that can pick up signal 360 degree's so that i just have to put it up? Or do they need to be pointed a certain way? My budget is $150.

You should have excellent results with the Channel Master 4221 pointed at 48 degrees. (The ones that claim to get good reception from all directions don't.) Terk is not highly regarded, as their antennas tend to perform worse than antennas available for half or even a third of the price. The 4221 is smallish (2'x4') and performs very well for UHF and hi-VHF (channels 7+.) Plus, it's not terribly expensive, doesn't "look" like an antenna, etc.

Several places sell them online, or you might be able to find a local dealer who carries one.

cpcat

10-03-05, 12:40 PM

K Rock,
It looks to me that a CM 4221 should work fine for you. It is primarily a UHF antenna but should be fine for high band vhf at that distance as well (for your fox and abc). It appears that all stations are within a few degrees on the compass so you should be able to aim it and forget it.

The CM 3016 is fine for vhf but the CM 4221 should be better for all of those UHF channels. It's also smaller and less obtrusive. I couldn't get the link to the other antenna to work. Stay away from the SquareShooter as it will not perform well for vhf.

It's a shame you can't get those local folks to help you out. :(

You shouldn't need a preamp but try to keep your cable run as short as possible.

Let us know how it goes.

Bluestraw

10-03-05, 01:36 PM

I'm hoping someone could help me with this... I want to set up a HDTV receiver, but I really can't get a rooftop antenna installed :( Does anyone know if I could get an internal setup working perhaps?

My AntennaWeb results are below. I'm not too far from these stations, so is there a hope to get this without an external antenna? I don't want to invest in all the equipment just to find it isn't going to work!

yellow - uhf WXIX-DT 19.1 FOX NEWPORT KY 12° 7.2 29
yellow - uhf WLWT-DT 5.1 NBC CINCINNATI OH 22° 7.6 35
green - uhf WCET-DT 48.1 PBS CINCINNATI OH 22° 7.6 34
green - uhf WSTR-DT 64.1 WB CINCINNATI OH 15° 12.7 33
red - uhf WKRC-DT 12.1 CBS CINCINNATI OH 31° 7.6 31
red - vhf WCPO-DT 9.1 ABC CINCINNATI OH 30° 8.1 10

Thanks!!

deconvolver

10-03-05, 01:38 PM

I post this in the miami thread but never got a response, maybe one of you guys can help me, or atleast point me in the right direction.

I can honestly say i've never been more confused in my life. I have no clue what to do. I really don't want a huge ant. sticking up from my roof. I was thinging of something a little smaller. i have my HD Tivo from DTV as my set top box, but i'm so confused on what to get for my house. I don't want an over kill but don't want a sucky ant too.

http://www.squadxp.com/news/results.JPG

those are my results from antannaWeb. And i only care about channle 7-6 and 10. Though it would be nice to get those plus 33 and 39.

Also is there a nice cost effective ant that can pick up signal 360 degree's so that i just have to put it up? Or do they need to be pointed a certain way? My budget is $150.

I found this ant,

http://www.solidsignal.com/prod_dis...=HDTVS#dishpics

while at solid signal.com i don't know anything about this stuff so if terk sucks please let me know. IT's also very important to me that i get very nice crisp clear signal. My closest cross street is 162nd AVE. and 56th Street.

Also do any of you guys recommend me puting this ant. on the top top top part of my house right now my dtv ant is on the left right side of the house. if you see the pic below it would be on the right side 1st roof.

http://www.squadxp.com/news/house.jpg

Thanks and if anyone can point me to the right ANT. I would be most greatful.

i also found some of these ant. cheaper and seem to cover more distance.

http://www.solidsignal.com/prod_dis...zoom=zoom#xview CM3016

also saw the cm4248 n 3671
It should not be too difficult for you to get your digital local stations with an outdoor antenna. You should try to get a clear shot to the northest sky without any big trees right in the way if possible. You don't want an omni antenna because all your stations are in the same direction (northeast) so a directional antenna would work best. Yes, Terk is overpriced. There are many good choices from Channelmaster or Winegard, the main question is how big an antenna will you need. A Channelmaster set-up might be a CM 3016 or CM 3017 or CM3018 antenna plus a Spartan-3 0068 DSB pre-amp. A Winegard solution could be a PR-7010 or PR-7015 or PR-7032 antenna with an AP-8700 pre-amp. You could also use the Winegard 8700 pre-amp for better overload resistance with a Channelmaster antenna. A CM-3016 or Winegard PR-7010 antenna with a good pre-amp might be big enough if no trees are in the way; but you normally can't return an antenna if it turns out you need a bigger one.

terminaldawn

10-03-05, 01:45 PM

I appologize for this post because I really am clueless when it comes to OFF Air Attena HD terminology...

I just got a DirecTV HD TiVo installed with an Off Air Antenna and I am having trouble getting the WB (Channel # 18-1) in Milwaukee, WI. I get all other channels but 18-1. I was told that UPN (24-1) is broadcasted from the same tower, and I get that. So if that is true then I should be getting 18-1. I have no idea what kind of antenna it is that I have, its sitting next to the directv dish and it looks like a cake cooling rack LOL with two cross things on it pointing in the opposite direction as the DirecTV dish...

Does anyone know what kind of Off Air Antenna I have? Is it any good? I am guessing its not worth the $50 that direcTV charged me for it.

Any suggestions on what I can do to get this channel in would be greatly appreciated!!!!

Thanks,

J

deconvolver

10-03-05, 02:14 PM

Bluestraw

10-03-05, 02:24 PM

Sorry to repeat myself, but I found a better way to show the Antennaweb results :

I'm hoping someone could help me with this... I want to set up a HDTV receiver, but I really can't get a rooftop antenna installed :( Does anyone know if I could get an internal setup working perhaps?

My AntennaWeb results are below. I'm not too far from these stations, so is there a hope to get this without an external antenna? I don't want to invest in all the equipment just to find it isn't going to work!

http://img159.imageshack.us/img159/1344/antenna2fq.th.jpg (http://img159.imageshack.us/my.php?image=antenna2fq.jpg)

http://img159.imageshack.us/my.php?image=antenna2fq.jpg

Thanks!!

holl_ands

10-03-05, 03:41 PM

It's just a blur to me....

Bluestraw

10-03-05, 03:55 PM

It's just a blur to me....

Not sure if that was directed to my picture - but I added a URL (as well as the original clickable image) :)

Demobuf

10-03-05, 04:00 PM

terminaldawn

10-03-05, 04:07 PM

It sounds like you have a double bow-tie antenna which is an OK small UHF antenna. To do better would take a bigger antenna. WVTV on the fcc website is listed as operating at a temporary STA level of 18.9 KW with a construction permit for 850KW. I don't know if the construction is complete yet, you could ask for the status on your local forum.

THanks!

etcarroll

10-03-05, 04:22 PM

I think for the Hartford stations you'll need an antenna with a bit more gain. Search the forum for discussions on the CM 4228, 4221 and comparable Wineguards.

I recently bought an HDTV and I want to see what kind of HD channels I can receive OTA. I have been reading a lot on these forums, and i have a specific question. I live fairly far away from any towers. I approximately live at 42 degrees 18'55.90" N, 72 degrees 40'04.09". Roughly On Burts Pit Road between florence rd. and clement st. Northampton, MA 01062. Most of my signals come from Springfield or Hartford. (Most of these in the red or blue color at antennaweb) I was wondering if i would be able to mount a SS-1000 on my roof with a CM-7777 preamp and have a hope to get these signals. I also was wondering if the SS-2000 (built in pre-amp) would work just as well as the SS-1000 with the CM-7777 because it costs less that way.
Thanks again for making such a great forum. I have learned a lot in the last two days (back when i didn't even know what uhf/vhf meant) and would appreciate any information. Thanks.

holl_ands

10-03-05, 04:35 PM

BlueStraw: Indoor antenna should work just fine since you are so close with no hills in the way.
Don't use any amplified antennas, since they will be overloaded by WCVN, which is only 3.2 miles away.

Some of the better indoor antennas are the Terk HDTVi (which has collapsible Rabbit Ears for VHF WCPO-DT),
the Silver Shadow (similiar, but no Rabbit Ears) and the usual assortment of Loops with Rabbit Ears.

holl_ands

10-03-05, 04:42 PM

Hi all, I have looked through this forum re: OTA reception, and have not been able to really pin down if a bowtie, or a yagi antenna will work better in my situation. I currently have a small RShack yagi, that works OK, on a rotor outside my house at the roof line. I am about 30 miles away from the towers in either direction. My house is surrounded by very tall trees. Code will not allow me to install a tower.

On occasion when the wind is blowing, my signal goes in and out. I believe it has to do with the trees, and their branches.

I am thinking about upgrading to a different antenna, but I am unsure what to order.

4 or 8 bay bowtie, or a yagi with many elements.

What is the best option for reception in my situation.

Thanks
You sure the wind isn't blowing the Yagi around?

The CM4228 has the advantage of spreading out the antenna bow-tie receptors both vertically and horizontally.
This means that some of the bow-tie elements may still be receiving a usable signal
when other portions of the array suffer blockage as the trees blow back and forth

If that isn't enough, a horizontally stacked array of two antennas could help.

After that, fill up the chainsaw....

ckenisell

10-03-05, 05:02 PM

I haven't read this entire thread so please forgive me, but many times on this forum I have seen folks send a link to a web site, where you plug in your zip code and it will tell you the HD channels you should be able to receive and the best type of antenna for receiving them. Does anyone know that link? Thanks!

deconvolver

10-03-05, 05:04 PM

sregener

10-03-05, 05:07 PM

I have seen folks send a link to a web site, where you plug in your zip code and it will tell you the HD channels you should be able to receive and the best type of antenna for receiving them.

www.antennaweb.org

holl_ands

10-03-05, 05:20 PM

You should have excellent results with the Channel Master 4221 pointed at 48 degrees. (The ones that claim to get good reception from all directions don't.) Terk is not highly regarded, as their antennas tend to perform worse than antennas available for half or even a third of the price. The 4221 is smallish (2'x4') and performs very well for UHF and hi-VHF (channels 7+.) Plus, it's not terribly expensive, doesn't "look" like an antenna, etc.

Several places sell them online, or you might be able to find a local dealer who carries one.

Re K Rock XP in Miami:

Here is correct link for CM3016 combination VHF/UHF antenna:
http://www.solidsignal.com/prod_display.asp?main_cat=3&CAT=&PROD=ANC3016

Here is correct link for Terk HDTVS (i.e. W-G SquareShooter) antenna.
This is a low gain, overpriced antenna intended for urban environments,
and probably has insufficient gain in your location.
http://www.solidsignal.com/prod_display.asp?main_cat=3&CAT=&PROD=HDTVS

The CM4221 4-Bay should be a good choice, and will survive high winds better than the combo VHF/UHF antennas mentioned by deconvolver.

I would normally add the CM4228 8-Bay to the list, since it provides significantly higher gain than the CM4221 for VHF channels.
However in hurricane country, it's not such a good choice.

Bluestraw

10-03-05, 05:21 PM

Indoor antenna should work just fine since you are so close with no hills in the way.
Don't use any amplified antennas, since they will be overloaded by WCVN, which is only 3.2 miles away.

Some of the better indoor antennas are the Terk HDTVi (which has collapsible Rabbit Ears for VHF WCPO-DT),
the Silver Shadow (similiar, but no Rabbit Ears) and the usual assortment of Loops with Rabbit Ears.

Great! I took a look at that antenna, and I'm amazed it looks so small. Do you think I would get a reliable signal, or am I likely to see a lot of dropouts? Would it matter if it's 'pointing through walls' rather than by a window? This link shows my rough location, and I need to 'aim' at between 20 and 30 degrees for the ones I'm interested in - does this look okay?

http://maps.google.com/maps?q=+palmer+ct,+crestview+hills,+41017&spn=0.025403,0.056099&t=k&hl=en

Sorry for all the questions - I'm pretty new to this, and I REALLY appreciate the help!! Also, I did a quick search for the Terk, and saw some bad comments - is it really good ?!!

ckenisell

10-03-05, 05:29 PM

www.antennaweb.org

Thanks!

holl_ands

10-03-05, 05:44 PM

BlueStraw: Earlier, I used your antennaweb results to quickly navigate to your location (+/- a few houses).
There are no hills in the way and strong signals are coming via line-of-sight from towers less than 8 miles away,
except for (light green) PBS WPTO-DT which is 34.3 miles away.
This is ideal indoor reception distance, even if you have brick walls, etc.
Pointing out a window, or simply being close enough to pick up the leakage helps.
So does getting the antenna as high as possible (e.g. attic).

When you get to double or triple your distance, indoor antennas become more difficult.
[At 22 miles, I mounted mine 15 feet up at top of cathedral ceiling and only sometimes will I suffer dropouts.]

Yellow and green colors--should be no problem indoors.

ABC WCPO-DT in your list was red. When I was navigating antennaweb, it changed to yellow.
The FCC database says that it is only 16.3 kW, which I'm not sure is correct, since top four networks
in top 100 Nielsen DMA (your #33) were required to go to full power on 1Jul05.
Suggest you rerun it and move the location +/- a few houses and see if it changes. I've see oddball results like this before.

The only real challenge will be PBS WPTO-DT, which might offer different programs than your nearby PBS WCET-DT.

Bluestraw

10-03-05, 05:56 PM

holl_ands,

THANK YOU! I really appreciate that. Not so bothered about WPTO-DT - if I can get all the rest I'll be very happy :) Time to buy some equipment I think!

Nitewatchman

10-03-05, 07:51 PM

except for (light green) PBS WPTO-DT which is 34.3 miles away.

Actually, the antennaweb info for WPTO-DT transmitter location is incorrect. It's from their original CP, which was for WKOI/DT tower, located between Oxford+Trenton, Ohio. WPTO analog transmits from oxford. WPTO-DT however got a CP mod a few years ago to transmit from WXIX tower in Cincinnati, and are currently operating licensed facilities from there. Don't ask me why antennaweb's info hasn't been updated on that yet, but it certianly is wrong.

You'll find correct tower corrdinates for WPTO-DT here (under the entry for 'WPTO" digital 28 licensed facilities) :

http://www.fcc.gov/fcc-bin/tvq?state=&call=WPTO&arn=&city=&chan=&cha2=69&serv=&type=0&facid=&list=0&dist=&dlat2=&mlat2=&slat2=&dlon2=&mlon2=&slon2=&size=9

If you notice, it's the same coordinates for WXIX :

http://www.fcc.gov/fcc-bin/tvq?state=&call=WXIX&arn=&city=&chan=&cha2=69&serv=&type=0&facid=&list=0&dist=&dlat2=&mlat2=&slat2=&dlon2=&mlon2=&slon2=&size=9

A couple of other possibly important considerations to think about for Bluestraw's location, given a indoor antenna is to be used as well.

#1) May be WCET-DT 34 antenna pattern(shows about a .190 relative field value in his direction judging by his antennaweb info and adjusting for about 5 degrees magnetic deviation in this area) - which is about 7.7KW ERP squirted in his direction given their current 215KW ERP STA.

Update: OOPS! I must be dyslexic tonight. 22 degree bearing(w/magnetic deviation) to WCET, subtracting +5 degree magnetic deviation for our area would be approx. 197 degree true bearing from WCET, not approx. 164 as I "calucated" above. But, as it turns out the null is relatively the same, with .193 relative field strength value given for 200 degree true bearing.

See their antenna pattern info here(again they are currently using the 215KW ERP STA, although the pattern is the same for their Full power CP and their "previous" 7.7KW ERP STA) :

http://www.fcc.gov/fcc-bin/tvq?state=&call=WCET&arn=&city=&chan=&cha2=69&serv=&type=0&facid=&list=0&dist=&dlat2=&mlat2=&slat2=&dlon2=&mlon2=&slon2=&size=9

He'll still probably be able to get them OK,(we have folks in his area who have posted in our local threads they do get them fine with indoor antennas, but some of those folks have had problems with them even with big "Yagis" in the attic ....)

#2). And then there is WSTR-DT 33's Current antenna pattern - Not as significant a null in his direction at approx. .502 relative field value in his direction, but they're running a 17.1KW ERP STA currently. So, (.502x.502) X 17,100 watts = about 4.3 KW ERP squirted in his direction.

Update: I was dyslexic with this one, too, but this time things are a little better. 15 degrees to WSTR tower from Bluestem's place, correct for +5 degree deviation would be approx 190 degree bearing from WSTR's "star tower". No pattern rotation shown on FCC site, and a .688 relative field value shown for 190 degree true bearing from their tower ... (.688x.688)x 17,100 watts = 8.1 KW ERP sent in Bluestem's direction ...

also, That's of course assuming the antenna patterns shown on FCC site matches real world results .... It should (more or less), but I wouldn't necessarily count on it, although viewers experiences who are in the "nulls" of these antenna patterns seem to correspond well with the patterns shown on FCC site. For instance, WSTR-DT's biggest null sends 572 WATTS towards the SE of their tower(at 130 degrees), and I've yet to see any reports from anyone in that direction be able to receive them, even though there are quite populated areas of Cincinnati metro area in that direction ....

WSTR info from FCC site here (currently using 17.1KW ERP STA) :

http://www.fcc.gov/fcc-bin/tvq?state=&call=WSTR&arn=&city=&chan=&cha2=69&serv=&type=0&facid=&list=0&dist=&dlat2=&mlat2=&slat2=&dlon2=&mlon2=&slon2=&size=9

The FCC database says that it is only 16.3 kW, which I'm not sure is correct, since top four networks in top 100 Nielsen DMA (your #33) were required to go to full power on 1Jul05.
.

16.3KW ERP is correct for WCPO-DT, and is their Full power allocation. In fact, their full power allocation from FCC was 13.7KW ERP, they were recently able to "maximize" their signal to 16.3KW ERP. 4 It takes much less power on VHF to cover the service area than would be the case with UHF, although most hi-VHF full power DTV allocations are in the 30~60KW'ish range. However, in this particular case, there is also WBNS 10 Columbus, Ohio Service area that I suspect was likely an issue in their "full power" allocation from FCC. WBNS +WCPO towers are only 97 miles apart, both stations are running non-directional antenna patterns and both stations have service areas approximately 55~60 mile radius .....
[/QUOTE]

WPTO-DT, which might offer different programs than your nearby PBS WCET-DT.
.

They are different -- different programming/different SD multicast service, Different PBS HD schedule(WCET-DT/CET/PBS now runs PBS HD channel 24/7, WPTO-DT/ThinkTV runs PBS HD programming on their time shifted schedule, only on Sat+Sun nights for instance. More info+links to stations websites can be found in Cincy thread.

WCVN-DT (KET/PBS), by the way also runs different programming services, and a different HD schedule per their time shifted schedule with an emphasis on HD rather than widescreen upconverted programming.

Isn't it interesting that we have THREE PBS affiliated digital stations broadcasting from towers in Cincy/N KY less than 6 miles apart, TWO of them on towers less than 2 miles apart ..... What's more, WPTO-DT's sister station, WPTD-DT 58 Dayton runs entirely different programming schedule(PBS HD nightly 6pm~6am for instance) and Since Dayton antenna farm is only about 42~44 miles from Most Cincinnati Stations. Most Dayton stations coverage area in fact reaches nearly all of Cincinnati Metro Area, Including most of it in N KY, including Ft. Mitchell.

Nitewatchman

10-03-05, 08:18 PM

I'm hoping someone could help me with this... I want to set up a HDTV receiver, but I really can't get a rooftop antenna installed :( Does anyone know if I could get an internal setup working perhaps?

Bluestraw -- 1st off, I must apologize for getting your location "wrong" from the map you provided link to in Cincy thread. I didn't see the Ft mitchell address info, and had seen "turkey foot rd." on the map and for some reason had "remembered" it wrongly as being East of Cincinnati instead of in N Ky.

The good news is, we've had at least one fellow in Florence with no terrain issues(and on the "hill") to the north not only have good luck with Cincinnati stations with indoor antenna, but he could pick up MOST of the Dayton stations as well with a CM4248(and preamp - he was just lucky not to have overload/IM problems I guess) in the attic .... What's nice is, both Cincinnati+Dayton market stations are in pretty much the same direction from you. YMMV of course, and I'd recommend an outdoor antenna setup if at all possible if you want to try for Dayton.

BTW, HOA's can't legally prohibit you from installing an outdoor antenna on property you control if that's the "issue" you are having. Search this forum(here or hardware area) or see info on FCC site concerning FCC's OTARD rules.

The Bad news is, a preamp would probably be a good idea for you for Dayton, but not for Cincinnati. Also, you'd have a blow torch signal from WXIX-DT 29(Fox HD Cincinnati), and a probably relatively weak signal on 1st adjacent channel WRGT-DT 30 (Fox HD Dayton), and you have to pretty much "shoot right through" WXIX's tower to get WRGT-DT. Why need two Fox stations anyway? Well, perhaps because they often have different NFL Games/etc - There were Two of them from WRGT-DT Yesterday for instance, but only a 4pm game from WXIX-DT since the bengals were playing at home(and NFL TV rules concerning home games).

If I recall correctly, the "planning factor" for the cutoff point for DTV working "properly" on 1st adjacent channels concerning the expected selectivity of DTV receivers involves a 46 db or less difference in signal levels between 1st adacent channel stations. "real world" results with any given receiver may be better or worse than that, and co-located 1st adjacent channel stations work better. Such as WCET-DT 34/WLWT-DT 35, broadcasting off the same tower, or WPTO-DT 28/WXIX-DT 29, or even WCPO 9 analog WCPO-DT 10.

jagged

10-03-05, 09:23 PM

adriana

10-03-05, 09:49 PM

hey guys i just bought the set-top box and i got to say.......... I LOVEEEEEEEEEEEEEEEEEEEEEEEEEEEEEE ITTTTT!!!! thank you!!!!!!!!!!!!! the only thing i need now is the silver sensor

deconvolver

10-03-05, 11:42 PM

I live in Brighton, Ontario, right across the lake from Rochester NY. I want to purchase a new antenna to hopefully get HDTV broadcasts from Syracuse, Rochester, Buffalo and hopefully Toronto. I can get a good deal on an AntennaCraft HD1800. I've already got a rotor, a CM 7777 amplifier, and a 40' tower. I live about a half mile from the lake. Does this combo sound OK?

Thanx in advance.
I would recommend that you get a UHF only antenna (plus a VHF high antenna if you need a station broadcasting on 7-13). I would only suggest getting something like the HD1800 if you need VHF-low. Many people use a Channelmaster 4228 for its excellent UHF and not too awful VHF performance but I would suggest a big UHF Yaggi plus a separate VHF-high antenna instead because of the heavy wind load of the 4228. I have the Winegard PR-9032 UHF Yaggi and YA-1713 VHF-high Yaggi which I got from www.starkelectronic.com connected to a 7777 pre-amp (set the internal switch for two antennas) and get good results.

mvita

10-04-05, 12:11 AM

mgtr - Thanks for the info, appreciate it! I ended up using a similar approach, except that I placed the 28" twin-lead segment inside a piece of 1/2" PVC pipe, put caps on the ends, and drilled a couple holes in the middle of the pipe to allow the two leads to connect to a balun which hangs below. I flipped the "separate VHF" switch on the 7777 and and wired in the balun w/coax as you mention. For now, I've just attached the PVC piece horizontally to the mast of the Square Shooter with some cable ties. It's reasonably secure, though I may end up going back up there and screwing the PVC into the housing of the SS as you suggest.

The bottom line: my WESH-DT signal strength has gone from a flaky and inconsistent 65-70% to a pretty rock solid 92%. Not too bad for a few bucks in parts and a couple hours of time!

Thanks again for the help....

K Rock XP

10-04-05, 02:41 AM

Re K Rock XP in Miami:

Here is correct link for CM3016 combination VHF/UHF antenna:
http://www.solidsignal.com/prod_display.asp?main_cat=3&CAT=&PROD=ANC3016

Here is correct link for Terk HDTVS (i.e. W-G SquareShooter) antenna.
This is a low gain, overpriced antenna intended for urban environments,
and probably has insufficient gain in your location.
http://www.solidsignal.com/prod_display.asp?main_cat=3&CAT=&PROD=HDTVS

The CM4221 4-Bay should be a good choice, and will survive high winds better than the combo VHF/UHF antennas mentioned by deconvolver.

I would normally add the CM4228 8-Bay to the list, since it provides significantly higher gain than the CM4221 for VHF channels.
However in hurricane country, it's not such a good choice.

Thanks for all the feedback guys, you've made this a lot easier.

I have a few questions before making my purchase.

I really wanna get this done with one shot try. So i was thinking of going with the

http://www.solidsignal.com/prod_display.asp?PROD=ANC4228&xzoom=zoomC#xview
CM4228 8 Bay

I don't think that it is that big. so i wanted to use it. but it has no mask. Any idea where i can get one?

Also wanted to ask u guys what you think about puttin it on the top of the 1st floor, or should i put it all the way on the top of the house?

Thanks!!!

DR_LaRRY_PEpPeR

10-04-05, 08:51 AM

Bluestraw

10-04-05, 09:05 AM

Bluestraw -- 1st off, I must apologize for getting your location "wrong" from the map you provided link to in Cincy thread. I didn't see the Ft mitchell address info, and had seen "turkey foot rd." on the map and for some reason had "remembered" it wrongly as being East of Cincinnati instead of in N Ky.

The good news is, we've had at least one fellow in Florence with no terrain issues(and on the "hill") to the north not only have good luck with Cincinnati stations with indoor antenna, but he could pick up MOST of the Dayton stations as well with a CM4248(and preamp - he was just lucky not to have overload/IM problems I guess) in the attic .... What's nice is, both Cincinnati+Dayton market stations are in pretty much the same direction from you. YMMV of course, and I'd recommend an outdoor antenna setup if at all possible if you want to try for Dayton.

nitewatchman,

For sure - no need to apologise!! Your help on here is above and beyond what I could have hoped for - very kind of you. At the time I posted on the Cinci thread, I hadn't even considered an internal antenna, as I didn't think this would ever work, and it was only when I started reading this antenna thread that I thought maybe it could be the best solution. Thanks for the HOA advice - in fact, I thought I'd just try an internal one at first and see how it goes, and then maybe look 'outside' and face the 'antenna on the roof' issue at a later point. For sure it sounds like the Dayton stations are (in general) better, but maybe not worth it for me just yet!

Thanks again to you, and holl_ands, for the advice. I'll let you know how I get on!

sregener

10-04-05, 10:52 AM

I don't think that it is that big. so i wanted to use it. but it has no mask. Any idea where i can get one?

Also wanted to ask u guys what you think about puttin it on the top of the 1st floor, or should i put it all the way on the top of the house?

Do you mean, a "mast", not a "mask"? You can pick one up at most hardware stores. Radio Shack probably has them as well. But if you're doing an indoor install, you don't really need a "mast." Any old pipe would work, or you don't even need one if you can secure it using rope (not wire.)

Higher is better, so if you can get it up at the top of your house, that's great. But it never hurts to try it in lower locations and see how it works.

deconvolver

10-04-05, 10:58 AM

Thanks for all the feedback guys, you've made this a lot easier.

I have a few questions before making my purchase.

I really wanna get this done with one shot try. So i was thinking of going with the

http://www.solidsignal.com/prod_display.asp?PROD=ANC4228&xzoom=zoomC#xview
CM4228 8 Bay

I don't think that it is that big. so i wanted to use it. but it has no mask. Any idea where i can get one?

Also wanted to ask u guys what you think about puttin it on the top of the 1st floor, or should i put it all the way on the top of the house?

Thanks!!!
The good news about the 4228 is that it is not too bad for VHF-high (that you need for WSVN-DT and WPLG-DT); it is about as good as rabbit ears for WSVN-DT. I didn't recommend a 4221 because it is a poor VHF antenna and you wanted those 2 VHF stations see: http://www.hdtvprimer.com/ANTENNAS/comparing.html The 4228 is also an excellent UHF antenna so you probably don't need to mount it super high (unless a big conifer is in the way) or to use a pre-amp with it. I think it is big and ugly but if you like its looks then just make sure you give it a solid mount that can take the wind load.

bobchase

10-04-05, 02:02 PM

I seem to have adjusted a big Radio Shack attic antenna as much a I can, but a couple channels still aren't quite strong enough. I'm about 45 miles away and these are 2 1000kW stations. Yet I get a 120kW station a bit better and it's more off-axis! :confused: There is a Radio Shack amp after ~40' of RG-6. I realize that a pre-amp would be better, but this was done in '96... I don't know how much a pre-amp would cost, but probably more than I want to spend.

I was trying to figure out what else I could do inexpensively to boost my signal a bit more. I could add another UHF antenna and combine it with the other one, right? (Any splitter can be reversed?) I was wondering, since the UHF portion of the RS antenna looks pretty simple (it's called a Yagi/corner reflector, I believe?), could I try rigging up something myself at all? Can I put some sort of metal rods along a PVC pipe or piece of wood? (Or is it supposed to be conductive, since the RS looks like its UHF elements are touching the metal boom?) I think the elements would be half-wavelength, is that correct? And that 2 wires would be connected to a balun, etc. But I don't know about the spacing of elements or even if they are ALL wired up. Are only some ("collector" elements??) actually wired? You can have just a "straight section" without a corner reflector, right?

I'd like to make something myself for fun if it's fairly straightforward! :) I don't know how much "engineering" design is needed, but it doesn't need to be that good. Just something that can pick up a bit more signal. There seem to be some real gurus here that I hoped could give some info. Thanks! :cool:

Have you looked at the NTSC (analog) stations? Are they noisy or 'snowy'? Are there moving bars in the picture? These bars can be horizontal or diagonal. Generally they are moving up or down in the picture. There may be some noise (buzz) when the picture is very bright (a white background of a commercial for instance).

If it's a really big antenna and the biggest stations don't come in, you might want to try a $4.00, 6 dB pad in front of your amp. Or really splurge and get the $15 Radio Shack variable attenuator. From what you are describing, those stations are probably overloading the amp. Most of the signal meters on the digital STB's (Set Top Box) and the digital tuners in TV's give you a signal 'quality' readout, not a signal level readout. So they will read a 'low level' when actually the signal level is high. The signal quality would be low due to the amp. If this is the case, you would probably see the moving diagonal bars in an analog signal.

On the other hand, is the analogs are all snowy, then it's time to look for a new amp and, perhaps, a new antenna. But before we go through all of the permutations of antennas and amps, lets find out if you are overloaded or underloaded.

Bob Chase
KHWB-TV

K Rock XP

10-04-05, 02:28 PM

The good news about the 4228 is that it is not too bad for VHF-high (that you need for WSVN-DT and WPLG-DT); it is about as good as rabbit ears for WSVN-DT. I didn't recommend a 4221 because it is a poor VHF antenna and you wanted those 2 VHF stations see: http://www.hdtvprimer.com/ANTENNAS/comparing.html The 4228 is also an excellent UHF antenna so you probably don't need to mount it super high (unless a big conifer is in the way) or to use a pre-amp with it. I think it is big and ugly but if you like its looks then just make sure you give it a solid mount that can take the wind load.

Do you know of a nicer looking ANT. that can deliver as good as the 4228 or maybe even better than the 4228 (but looks nicer)?

Also i've hear you say pre amp a bunch of times. is that something that attaches to the ANT that boosts it's signal? and what part of the ANT would it go on? Maybe you have a pic that illustrates it.

sregener

10-04-05, 03:53 PM

Do you know of a nicer looking ANT. that can deliver as good as the 4228 or maybe even better than the 4228 (but looks nicer)?

Almost no antenna on the market works better than the 4228. And looks are somewhat subjective. Maybe you'd think this looks better: http://www.winegard.com/offair/pdf/hd8200p.pdf :eek:

deconvolver

10-04-05, 04:01 PM

Do you know of a nicer looking ANT. that can deliver as good as the 4228 or maybe even better than the 4228 (but looks nicer)?

Also i've hear you say pre amp a bunch of times. is that something that attaches to the ANT that boosts it's signal? and what part of the ANT would it go on? Maybe you have a pic that illustrates it.
The pre amp does attach near the antenna to boost the signal before the RG-6 downlead. A good one will have a lower noise figure than your HDTV receiver and will get the UHF signal before the downlead losses so the net result can be a significantly improved signal. One potential problem with an amplifier is if even one channel gets boosted too high it can ruin all of your reception. So if you have a clear shot to a strong station less than say 12 miles away a pre-amplifier is normally not recommended- but if you can use one it can help you use a smaller antenna especially for UHF. A good pre-amp that does not overload too easily is a Winegard AP-8700 (UHF & VHF combined) or AP-2870 (UHF and VHF separate). The Winegard HDP-269 (UHF & VHF combined) is even more resistant to overloading than the AP-8700 because it has less gain so it could be a good choice too. These and the Winegard AP-4700 (UHF amplification only) all have lower noise figures than most any receiver so they should improve your reception if not overloaded.

I personally like the look of a more horizontal antenna so that is why I recommended a small combo antenna with maybe a pre-amp to improve the UHF. I think that separate UHF and VHF-high Yaggis are the best looking antennas but then you would have two antennas instead of one. That configuration could be a Winegard PR-9018 or 9022 for UHF at the very top of the mast and a Winegard YA-6713 for VHF-high nearer the bottom of the mast with the PR-9018 or 9022 amplified with an AP-4700 or both UHF & VHF connected to an AP-2870. That combo without the pre-amp would have better VHF-high performance than a CM-4228 but to have UHF performance similar to a 4228 would take a PR-9032.

deconvolver

10-04-05, 04:16 PM

Almost no antenna on the market works better than the 4228. And looks are somewhat subjective. Maybe you'd think this looks better: http://www.winegard.com/offair/pdf/hd8200p.pdf :eek:
Of course the 4228 is only good for UHF; for VHF-high it is merely not too awful and for VHF-low it stinks. The reason the HD8200 is so huge is that it is designed to include good VHF-low performance. And by-the way I do think it looks good for the size :)

cpcat

10-04-05, 04:31 PM

holl_ands

10-04-05, 05:33 PM

I'd try the CM 4221 alone first. I really don't think you need the 4228 and that will be alot of wind load in Miami.

You could add a small hi band vhf like an antennacraft Y5 7-13 later if necessary and still end up with less load on the mast than a single 4228. You could even make a channel 8 or 9 dipole very easily.

I bet the 4221 will work for everything at that distance though.

I'd try without a preamp first as well. If you have alot of splits and cable run, just add an indoor line amp.

I completely agree with the above approach. CM4221 should be adequate for upper (CH7-13) VHF channels.

Although C-M and W-B don't publish VHF specs for their 4-Bay antennas, Dipol does:
http://www.dipol.com.pl/kat01a.pdf
Note that gain is in dBi vs the usual dBd (dBd = dBi - 2.15 dB).
So their 4-Bay has 8-12 dBd gain for UHF and 4-5 dB gain for our VHF CH7-13
(that's Polish CH6-11, cuz they use 8 MHz channels).

The top row are unamplified 4-Bay Reflectors, the second row are amplified as reflected in the total gain figure.
The bottom row are interesting, since they use either inductive "looping" of the elements or a whisker extension to enhance VHF operation.

deconvolver

10-04-05, 05:40 PM

I'd try the CM 4221 alone first. I really don't think you need the 4228 and that will be alot of wind load in Miami.

You could add a small hi band vhf like an antennacraft Y5 7-13 later if necessary and still end up with less load on the mast than a single 4228. You could even make a channel 8 or 9 dipole very easily.

I bet the 4221 will work for everything at that distance though.

I'd try without a preamp first as well. If you have alot of splits and cable run, just add an indoor line amp.
This is close to what I was thinking, a UHF antenna and a small VHF-high antenna. If you mount a good distribution amp like one of the Channelmaster ones (CM 3042, 3043, or 3044 depending on the number of TVs connected) near where the cable enters the house you would probably get most of the benefit of a pre-amp more cheaply (assuming the noise figure is correct). You could of course start with just the UHF antenna and add a VHF-high antenna and/or amp only if necessary. The 4221 is a better antenna than a small corner reflector UHF Yaggi; I just like the look of the Yaggi better.

deconvolver

10-04-05, 05:43 PM

I completely agree with the above approach. CM4221 should be adequate for upper (CH7-13) VHF channels.

Although C-M and W-B don't publish VHF specs for their 4-Bay antennas, Dipol does:
http://www.dipol.com.pl/kat01a.pdf
Note that gain is in dBi vs the usual dBd (dBd = dBi - 2.15 dB).
So their 4-Bay has 8-12 dBd gain for UHF and 4-5 dB gain for our VHF CH7-13
(that's Polish CH6-11, cuz they use 8 MHz channels).

The top row are unamplified 4-Bay Reflectors, the second row are amplified as reflected in the total gain figure.
The bottom row are interesting, since they use either inductive "looping" of the elements or a whisker extension to enhance VHF operation.
The 4221 lacks the VHF matching so its modelled performance for channel 8 was not good.

holl_ands

10-04-05, 06:07 PM

I would not use any of the Channel Master Preamps 20 miles away from broadcast towers because
the dynamic range (i.e. SFDR) will be insufficient due to operating in the non-linear amplification region.

Go with one of the LOWER GAIN Winegard Preamp models, such as AP-8700/8703 or HDP-269.
This subject was discussed at length in the fol. thread:
http://www.avsforum.com/avs-vb/showthread.php?p=6293078#post6293078

====================================================
So do you have some NEC modeling results that are better than those found on www.hdtvprimer.com?

====================================================
FYI: If you check the next few pages in the Dipol catalog, you'll also find specs for the ATX-91 (91XG),
and what looks like a "DAT-37" and "DAT-45".

cpcat

10-04-05, 06:10 PM

If you mount a good distribution amp like one of the Channelmaster ones (CM 3042, 3043, or 3044 depending on the number of TVs connected) near where the cable enters the house you would probably get most of the benefit of a pre-amp more cheaply (assuming the noise figure is correct). .

A line amp will also be more immune to overload that close in. The CM models you mention are available at Lowe's.

holl_ands

10-04-05, 06:17 PM

deconvolver

10-04-05, 08:14 PM

...
====================================================
So do you have some NEC modeling results that are better than those found on www.hdtvprimer.com?

====================================================
FYI: If you check the next few pages in the Dipol catalog, you'll also find specs for the ATX-91 (91XG),
and what looks like a "DAT-37" and "DAT-45".
It is the hdtvprimer modelling result that I was referring to when I said the 4221 is not matched well at channel 8. I have tweaked the model for the 9032 to better match the drop in performance that Winegard shows near channel 69 with the result that lower channel gain improves because the whole curve shifted to the left. A really improved model of the 9032 would need to more accurately include the effect of the broad flat elements as well as the lengthening effect of the electrically connected conductive boom. I am not surprised by Winegard's plots of other antennas where the gain is a couple of dB too high because I think they use a ground reflection to augment their measured gains. What I don't know is if the PR-9032 really has a broad high-gain curve like Winegard shows. From the given beamwidths I expect that they just adjusted for maximum ground bounce enhancement near channel 32 and that the correct free-field curve for the 9032 would have the shape of what hdtvprimer shows just shifted to the left a bit.

deconvolver

10-04-05, 08:34 PM

...
====================================================
FYI: If you check the next few pages in the Dipol catalog, you'll also find specs for the ATX-91 (91XG),
and what looks like a "DAT-37" and "DAT-45".
I don't claim to be able to read those pages but it looks like they are showing raw gain not net gain. Many UHF antennas have pretty good raw gain for VHF-high but that doesn't mean the VSWR isn't so bad that the net gain is poor. That would be the problem for the CM 4221, DB-2 and square shooter that hdtvprimer shows poor VHF net gains for.

cpcat

10-04-05, 08:45 PM

Line Amps and Distribution Amps do NOT have higher input overload capability than a W-G Low Gain Preamp.
If they did, we would be tie-wrapping them to the top of the antenna mast.
They also have lower sensitivity. Check the specs!!!

Most line amps have input overload numbers which are rated for say 30-40 channels or even more. Preamp ratings are usually for 2 or at most 4 channels, so you can't really compare the specs.

The line amp is designed for higher resistance to input overload and higher output capability, the preamp typically is designed for low noise. That's the main difference, really, between the two.

DR_LaRRY_PEpPeR

10-05-05, 12:38 AM

Have you looked at the NTSC (analog) stations? Are they noisy or 'snowy'? Are there moving bars in the picture? These bars can be horizontal or diagonal. Generally they are moving up or down in the picture. There may be some noise (buzz) when the picture is very bright (a white background of a commercial for instance).

If it's a really big antenna and the biggest stations don't come in, you might want to try a $4.00, 6 dB pad in front of your amp. Or really splurge and get the $15 Radio Shack variable attenuator. From what you are describing, those stations are probably overloading the amp. Most of the signal meters on the digital STB's (Set Top Box) and the digital tuners in TV's give you a signal 'quality' readout, not a signal level readout. So they will read a 'low level' when actually the signal level is high. The signal quality would be low due to the amp. If this is the case, you would probably see the moving diagonal bars in an analog signal.

On the other hand, is the analogs are all snowy, then it's time to look for a new amp and, perhaps, a new antenna. But before we go through all of the permutations of antennas and amps, lets find out if you are overloaded or underloaded.

Bob Chase
KHWB-TV

Thanks for the reply Bob. :) Sorry I didn't include more information, as my question was mainly whether I could make a DIY UHF antenna for cheap. Here's my station info:

Channel Direction Miles ERP (kW)
KTVI 2 (43) 105.5 43.1 1000
KMOV 4 (56) 104.6 47.1 1000
KSDK 5 (35) 101.9 44.7 838
KETC 9 (39) 110.7 43.0 125
KPLR 11 (26) 101.4 45.0 1000
KDNL 30 (31) 100.8 44.7 1000
WRBU 46 (47) 121.5 41.6 109

My antenna is at ~102 degrees. (It was at about 80 since '96 till I re-aimed a couple weeks ago, before I got the DTV receiver.) The side of the house is at ~75 degrees; so, the antenna is around 27 degrees to the right of that in the attic. The signal is coming through the [relatively steep] roof (1/2", I assume, plywood + asphalt shingles) at a lower angle than it would through the side wall (which would be closer to perpendicular, if that matters). I can't aim through the wall because of the antenna length (I think it's the 120", rated for 120/90mi VHF/UHF), the angle, and limited width (front to back of house) up there, which is basically all used now. It's in the second story attic, so about 20' off the ground. I just raised the front of it yesterday almost 3' I guess, so it's aimed upward ~10-15 degrees. Does that hurt? Well, it didn't help much anyway, though I thought it did at first last night...

Now for my channels... I don't think I'm overloaded. As far as analog channels go, VHF channels 2-11 come in about as well as expected. Before moving the antenna from the ~80 degree position, channel 9 had rolling horizontal bars, and 11 had pretty bad snow (its analog transmitter is in a different position than the digital one). Now 9 is great, and 11 only has minor/light snow. Channel 30 has always been the worst, and it's the best it's been now, with moderate snow. The picture is clear "enough" that you could watch a program and see what's going on OK, to give you an idea. It's 2190kW analog. Channel 46 looks like satellite from 20' away (5000kW). Other than very minor noise/static (2-9) or snow (11, 30) there are no other analog problems like ghosting, bars, etc.

The best digital channel is 4. It's mostly fine, worst signal is ~60% and goes as high as 90 after midnight; only rare minor breakups. 46 is next, mostly fine. 2 and 5: about the same -- signal jumping around below 50% during the day, into the 60s easily at night and basically as stable then as 4. 11 and 30 are the ones I'm having trouble with. They don't go higher than 40% during the day, even down to 0 every few seconds and don't come in. They're in the 50s at night (couple hours after sunset), but have too much breakup to be watchable. Sometimes they'll be fine for a couple minutes. I can't get channel 9 at all, but I didn't necessarily expect to (I'd LIKE to however). It jumps from 0 to ~30% in 1 or 2 second intervals. One time last week during late night/early morning, it did get into the high 40s for me to see mostly a full picture for a short time.

It sure seems weird that I get 46 so well at 1/9 the power. :confused: I could probably aim another UHF antenna through the side wall if that would be better. But like I said/asked, I don't know if I can make my own. :)

K Rock XP

10-05-05, 02:52 AM

Of course the 4228 is only good for UHF; for VHF-high it is merely not too awful and for VHF-low it stinks. The reason the HD8200 is so huge is that it is designed to include good VHF-low performance. And by-the way I do think it looks good for the size :)

whats ment by the VHF low?

K Rock XP

10-05-05, 02:56 AM

holl_ands

10-05-05, 03:18 AM

DR_LaRRY_PEpPeR

10-05-05, 05:31 AM

bbig119

10-05-05, 09:38 AM

Question: And I've posted in my local thread already, but I'd like to get more broad opinions on this.

I'm in Lansdowne PA, about 7-8 miles from all the major local antennas in Philly. I'm currently trying to get a stable OTA signal to work. Initally I was testing the waters and bought a Terk HDTVi from ratshack with full intention of returning it. I was able to lock on the majority of the channels, but saw frequent dropouts. I then discovered an old antenna on the top of the house I just moved into, and went up to try and hook it up. This antenna is rusted to the mast, and unable to be adjusted, but fortunately it appears to be aimed in generally the correct direction. I jerryrigged a coax wire to the 300 ohm ribbon wire leads from the antenna, and ok-- I saw a slight improvement but still unwatchable dropouts on almost every station.

I've heard that there is no reason why I shouldn't be able to pick up all these stations easily with an indoor antenna- the Silver Senor has been recommended and a relatively cheap $15 ratshack antenna has also been mentioned several times as being good.

I'd like to get a more stable solid signal, which I know I should be able to get without spending tons of money on a monster antenna, but I'm not sure if I should get one of these indoor antennas or look to get a new outdoor antenna to replace the old rusted monster on the roof.

Any thoughts?

Thanks

K Rock XP

10-05-05, 11:26 AM

i've tried a indoor ant and it didn't work. i have tons of electronics, maybe thats why. Once i ge the ant all set up i'll let you guys know.

deconvolver

10-05-05, 11:53 AM

VHF-low is Channel 2-6, which is followed by FM stations and other services and VHF-high is Channel 7-13.

Although WSVM-DT amd WPLG-DT aren't the most powerful VHF stations,
bear in mind that you are only 23 miles away over flat land.
Indoor Rabbit Ears might even work for these stations.....huge VHF antenna is overkill.

I do hope that deconvolver has tongue firmly in cheek re the monster antenna....
Luckily there will probably be only about a half dozen VHF-low stations for the entire country after the digital transition and those will be located mainly in sparsely populated areas. So, the need for monster antennas is pretty much a thing of the past. The VHF portion of the HD8200 reminds me of a big antenna with a guyed mast we had on the house where I grew up so the look is kind of nostalgic for me. I though that antenna looked great when I was a kid until we had an ice storm. After that it looked kind of sad.

K Rock XP

10-05-05, 12:51 PM

Luckily there will probably be only about a half dozen VHF-low stations for the entire country after the digital transition and those will be located mainly in sparsely populated areas. So, the need for monster antennas is pretty much a thing of the past. The VHF portion of the HD8200 reminds me of a big antenna with a guyed mast we had on the house where I grew up so the look is kind of nostalgic for me. I though that antenna looked great when I was a kid until we had an ice storm. After that it looked kind of sad.

Well i've come to terms with getting the 4228 8 Bay. was wondering something though. If you go to the link below u can see it only says UHF. does that mean it doens't accept VHF?

http://www.solidsignal.com/prod_display.asp?PROD=ANC4228&

HDTVChallenged

10-05-05, 01:01 PM

Well i've come to terms with getting the 4228 8 Bay. was wondering something though. If you go to the link below u can see it only says UHF. does that mean it doens't accept VHF?

Try here (http://www.hdtvprimer.com/ANTENNAS/comparing.html) for a full explaination of why the CM4228 works for VHF-hi. Scroll to the bottom of the page.

Personally, I suspect that the coupling transmission lines act as reasonable VHF-hi dipole, others think the screen has a part to play.

K Rock XP

10-05-05, 01:12 PM

well in my area channel 7 and 10 are VHF. Are those considered Low? And will i get a degraded signal as a result from using the 4228 8 bay? :confused:

Thanks and sorry for all the questions.

deconvolver

10-05-05, 02:05 PM

well in my area channel 7 and 10 are VHF. Are those considered Low? And will i get a degraded signal as a result from using the 4228 8 bay? :confused:

Thanks and sorry for all the questions.
No, 7 and 10 are transmitted digitally on channels 8 and 9 (from the last column in your antennaweb results) so they are VHF-high. I'm sorry I continued the joking about VHF-low antennas because they aren't needed by almost anyone for digital TV. The 4228 8-bay is a not-too bad antenna for VHF-high; it should be much better for that than a 4221. If you mounted rabbit ears on your roof they would probably work for your VHF channels and the 4228 is as good as or better than rabbit ears so I expect that the 4228 would be OK. It is way more UHF antenna than you need though so you could go with a smaller UHF antenna plus a small VHF-high antenna instead if you think that looks better.

MHD1080

10-05-05, 02:16 PM

Which Is Better Db8 Or Cm4228 Antenna?

deconvolver

10-05-05, 02:17 PM

Well i've come to terms with getting the 4228 8 Bay. was wondering something though. If you go to the link below u can see it only says UHF. does that mean it doens't accept VHF?

http://www.solidsignal.com/prod_display.asp?PROD=ANC4228&
I wonder if you have an exterior wall on your second story that faces North-East. If you do then you might be able to mount the 4228 against the outside of that wall thus protecting it from the wind and also making it stand out less. Just a thought. A normal mount with a well secured strong mast should work.

deconvolver

10-05-05, 02:51 PM

Which Is Better Db8 Or Cm4228 Antenna?
For VHF-high the CM 4228 is considered much better than the other 8 bay's because of the effectively continuous screen refector and the way the feed works. I think for UHF there is not that big a difference. The 4228 is a safe choice because so many on the forums have had good results with it.

MHD1080

10-05-05, 03:36 PM

Db8 Is Suppose To Have A 90 Degree Beam Unlike The Cm4228 Which Is Only 10 To 15 Degrees

deconvolver

10-05-05, 05:17 PM

Db8 Is Suppose To Have A 90 Degree Beam Unlike The Cm4228 Which Is Only 10 To 15 Degrees
Antennasdirect labels the DB8 as a multidirectional antenna but they are wrong. Its beamwidth is about the same as the 4228. If you could figure out a way to mount all 8 bays vertically then it would have a wider horizontal and narrower vertical beamwidth than a CM-4228 but as shown they will be about the same. I can't think of a reason to get the more expensive dB8.

deconvolver

10-05-05, 06:00 PM

I seem to have adjusted a big Radio Shack attic antenna as much a I can, but a couple channels still aren't quite strong enough. I'm about 45 miles away and these are 2 1000kW stations. Yet I get a 120kW station a bit better and it's more off-axis! :confused: There is a Radio Shack amp after ~40' of RG-6. I realize that a pre-amp would be better, but this was done in '96... I don't know how much a pre-amp would cost, but probably more than I want to spend.

I was trying to figure out what else I could do inexpensively to boost my signal a bit more. I could add another UHF antenna and combine it with the other one, right? (Any splitter can be reversed?) I was wondering, since the UHF portion of the RS antenna looks pretty simple (it's called a Yagi/corner reflector, I believe?), could I try rigging up something myself at all? Can I put some sort of metal rods along a PVC pipe or piece of wood? (Or is it supposed to be conductive, since the RS looks like its UHF elements are touching the metal boom?) I think the elements would be half-wavelength, is that correct? And that 2 wires would be connected to a balun, etc. But I don't know about the spacing of elements or even if they are ALL wired up. Are only some ("collector" elements??) actually wired? You can have just a "straight section" without a corner reflector, right?

I'd like to make something myself for fun if it's fairly straightforward! :) I don't know how much "engineering" design is needed, but it doesn't need to be that good. Just something that can pick up a bit more signal. There seem to be some real gurus here that I hoped could give some info. Thanks! :cool:
Wideband UHF antennas are not simple to design and construct. Yaggi designs must be de-tuned and multibay bow-ties seem simple only until you try to feed them. I would expect that if you work hard you could make an antenna almost as good as what you already have. Good UHF antennas are not expensive so why not just buy one? The 4228 is a good safe choice. A Winegard PR-9032 is even cheaper and should also work for you if it will fit and you don't put it in a dead spot. Even if turning down the gain makes things worse the front end of your amplifier could still be overloading or unstable; eliminating it and getting a better one would be a good idea. The Winegard AP-2870 is a good pre-amp with inputs for separate UHF and VHF antennas. If you have power in your attic you could also put a distribution amp like a CM-3042 in there which would be cheaper than a pre-amp.

bobchase

10-05-05, 08:42 PM

I forgot to say about overloading and the amplifier -- when the amp is turned down or removed, the signal meter on the DTV receiver goes DOWN and analog channels get worse. So that should rule out overloading, shouldn't it? Also that the reception is better at night -- because signals get better then, not worse, right?

I just found the Service Area Maps on the FCC site and I'm within the area for all channels (I was surprised by how far they're supposed to go! :)). Way within the area of the full power stations. I'm even within the area for a 63kW independent station 40 miles away... Of course it must not take into account the terrain for specific areas, but I can't SEE any hills/obstructions in the direction of the transmitters. It's wooded area all around which makes it hard to see very far, but the few closest to the house (30' away) don't look like they should be a problem. I could probably go out on the roof and take a picture to post. :)

The signals are obviously getting here a bit, but not with enough strength (assuming NOT overloaded), either because of the antenna, roof, or something.
If by worse, you mean snowier, then I'd say that you are not in amplifier overload. Attics are funny things in the land of RF. I have measured losses in three attics now and found them to be in the 15 to 20 dB range (which compares to a 60's study I once read). That's more gain than an antenna has, most of the gain of any amp that you were to use, and more gain than some amps even offer.

It sounds like you've tried to redirect the antenna at least once. If lifting the front 3' to get it pointed correctly is what it took, then no, it's not a problem. Consumer antennas are not very directional in the vertical axis. Even outside on the roof tilting them up or down 10 degrees has little effect on received level.

If you could identify the amp you have (make & model number) perhaps a few of us could figure out if there would be a chance of an improvement. I'd love to tell you to go out and spend the money on a Channel Master 7777 pre-amp to replace your present amp. But there is no guarantee that it will work any better - not by remote control from afar.

Bob Chase

DR_LaRRY_PEpPeR

10-06-05, 12:34 AM

Wideband UHF antennas are not simple to design and construct. Yaggi designs must be de-tuned and multibay bow-ties seem simple only until you try to feed them. I would expect that if you work hard you could make an antenna almost as good as what you already have.

What kind of work would I need to do? :) Are there any sites around that have instructions? A quick Google search only turned up things about antenna theory/physics, rather than actually building something...

If by worse, you mean snowier, then I'd say that you are not in amplifier overload. Attics are funny things in the land of RF. I have measured losses in three attics now and found them to be in the 15 to 20 dB range (which compares to a 60's study I once read). That's more gain than an antenna has, most of the gain of any amp that you were to use, and more gain than some amps even offer.

Yeah, I mean snowier. :) I recently saw your 15-20dB attic attenuation stats, and thought, "Woah!" ;) On this HDTV Primer page (www.hdtvprimer.com/ANTENNAS/sizing.html) (under "Additional Corrections" at the bottom) I had read only 4dB in the attic. :( :mad: Any idea why the weaker 46 gets through fine?

It would probably do fine if it was moved outside (I'd probably get channel 9 if it was 15-20 dB better!). It just seems like such a pain (maybe I'm making it seem worse) to put it outside, with the mounting (and deciding where to put it to stay safe on the steep roof, etc.) and figuring out where to run the coax and grounding wire. Also, on my antenna, some of the plastic snap-in things for the VHF elements got broke while trying to weave them between the trusses in the attic, so I don't know if they'd stay in position in the wind... AND I can't find the box it came in anymore, which I think had some mounting hardware, like another support boom section that goes under the main boom.

It sounds like you've tried to redirect the antenna at least once. If lifting the front 3' to get it pointed correctly is what it took, then no, it's not a problem. Consumer antennas are not very directional in the vertical axis. Even outside on the roof tilting them up or down 10 degrees has little effect on received level.

Didn't help much. And I'm sure it was the front being higher that helped, not the angle. I couldn't raise the other end because the VHF elements are almost hitting the roof where it is. Haha

If you could identify the amp you have (make & model number) perhaps a few of us could figure out if there would be a chance of an improvement. I'd love to tell you to go out and spend the money on a Channel Master 7777 pre-amp to replace your present amp. But there is no guarantee that it will work any better - not by remote control from afar.

I just checked and it's the Radio Shack 15-1113B. It's from '96, but I found the manual at the RS site. The manual's specs "say" the gain is adjustable between 15-25dB and the noise figure is 6dB.

BTW, there's nearly 50' of old RG-59 from '96 with "twist-on" connectors after the amplifier. I think that looses ~3dB @ 700MHz. There's also a 3-way splitter that I tried removing with no change at all. I don't think there's any problem with the stuff after the amp, as I connected a receiver where the amp would be (so the amp was out of the loop), and had the same result as going the whole distance without the amp -- only 4 and 46 came in I believe.

holl_ands

10-06-05, 03:12 AM

Try here (http://www.hdtvprimer.com/ANTENNAS/comparing.html) for a full explaination of why the CM4228 works for VHF-hi. Scroll to the bottom of the page.

Personally, I suspect that the coupling transmission lines act as reasonable VHF-hi dipole, others think the screen has a part to play.

1. The above NEC Simulation runs show the CM4228 to have significantly higher gain than the PR8800 in the VHF region.
Also note the gain of the CM4221 4-Bay is much, much less than either 8-Bay.
Unfortunately, simulations always seem to be a pale avatar for the real thing, so...

2. Here is a link to Kerry Cozad's antenna range test, where I blew up the VHF gain curves so you can see them:
http://hdtv.forsandiego.com/messages/1/3476.html#POST19916
The UHF gain for the CM4228 was well above C-M's spec numbers and the
upper VHF (CH7-13) gain was significant, although not as much as some purpose built VHF antennas.
Gain for lower VHF (CH2-6) was much less, but most combination VHF/UHF antennas don't have much gain
in this region either because they are considerably smaller than a half-wavelength.
Fortunately, free-space-loss is much less for VHF than UHF.

3. Also see bobchase's 3/28/05 outdoor vs attic antenna comparison tests:
http://www.avsforum.com/avs-vb/attachment.php?attachmentid=35460
and his more recent 9/24/05 post with on-air antenna comparison tests:
http://www.avsforum.com/avs-vb/attachment.php?attachmentid=43178
CM4228 was only a few dB less gain than the mid to best VHF antennas.

4. And another extensive on-air comparison test:
http://www.atechfabrication.com/reception_solutions.htm

5. The big difference in construction between the CM4228 and the other 8-Bay antennas
(W-G PR8800 and A-D DB-8) is the feed structure....and a screen vs resonating reflector elements:
http://www.solidsignal.com/prod_display.asp?PROD=ANC4228&xzoom=zoom#xview
http://www.winegard.com/offair/pdf/pr-8800.pdf
http://www.antennasdirect.com/DB8_HD_Antenna.html

The latter two antennas appear to use an RF Combiner, such as is used for Stacked Antennas.
At UHF, this results in about 0.5 dB of loss when the responses of the 4-Bay sections are
perfectly matched and even more when they are not.
At VHF, the individual 4-Bay sections are too small to have much gain and when the RF Combiner
sums them together, the result is much less than the CM4228.

From the center feed point, the CM4228 uses half-wavelength (at UHF) feeds to
each of the two 4-Bay Bowtie arrays, rather than an RF Combiner.
For VHF frequencies, the CM4228 feed lines are much less than a wavelength and indeed look more like a
center-fed dipole with huge capacity hats (the 4-Bay's) on each end, which tends to broaden the bandwidth.
Imagine one huge Bow-Tie element that is center fed and then spreads out to form a very fat dipole.

6. I have not seen any NEC Simulation data on whether connecting the CM4228's two reflector screens together
makes any difference between letting them operate independently.

I would be interested if anyone has done any runs, because today I bought a CM4228 to upgrade my son's CM4221.
[In SOCAL, Santa Ana heat winds cause temperature inversions....which result in signal difficulties....and wildfires...]

MHD1080

10-06-05, 08:55 AM

deconvolver

10-06-05, 08:56 AM

What kind of work would I need to do? :) Are there any sites around that have instructions? A quick Google search only turned up things about antenna theory/physics, rather than actually building something...

I just checked and it's the Radio Shack 15-1113B. It's from '96, but I found the manual at the RS site. The manual's specs "say" the gain is adjustable between 15-25dB and the noise figure is 6dB.

I know that radio amateurs build antennas so I checked the ARRL site. For only $5 more than the excellent Winegard PR-9032 antenna costs you can buy the ARRL antenna book:
http://www.arrl.org/catalog/index.php3?category=Antennas%2C+Transmission+Lines+%26+Propa gation

A 6 dB noise figure is poor for an antenna amplifier. If you switched to one of the amplifiers I listed before it would be like doubling the size of your antenna. The CM-7777 has an even lower noise factor at 2.2dB and more gain than the ones I listed but it is much more likely to overload.

MHD1080

10-06-05, 08:56 AM

Plus Channel 4 Sucks In A Different Location 179 Degrees

MHD1080

10-06-05, 09:07 AM

Either Antenna Is Going To Be Angled Up Cause I'm Behind A Hill

deconvolver

10-06-05, 09:14 AM

Do You Have Any Field Tests To Show Db8 And The Cm4228 Being The Same,cause I Was Looking For A Bigger Beam Cause My 2,11,13,16,22,53 Our Betwween 301 Degrees And 315 Degrees And Don't Want To Have A Rotor
The beamwidth will be determined by the antenna design. There is no way that that antenna with the side by side bowties will have a wide beamwidth. In fact the gain of an antenna is determined by how directional the antenna is- the more directional then the more gain (with one mainlobe the gain is proportional to the reciprical of the product of the vertical and horizontal beamwidths). I have done NEC simulations of 8 bay bowties and the exact beamwidth will be determined by the center to center horizontal spacing of the bowties which is similar between the DB-8 and CM-4228. As I said before if you can figure out a way to mount all 8 bowties vertically then the horizontal beamwidth will be wider. Or you could just use a vertical stack of two CM-4221.

MHD1080

10-06-05, 09:19 AM

So What Is The True Beam Width For These Antenna S ? Would I Be Able To Pick Up Those Channels Up With Them Being Between 301 And 315 Degrees?

deconvolver

10-06-05, 09:34 AM

So What Is The True Beam Width For These Antenna S ? Would I Be Able To Pick Up Those Channels Up With Them Being Between 301 And 315 Degrees?
The beamwidth scales inversely with frequency so you need the real transmit channel (the last column from antennaweb.org output). I don't know the exact bowtie to bowtie horizontal spacing for the DB-8 but it looks about the same in the pictures as the CM4228. Why not use one or two vertically stacked 4221?

MHD1080

10-06-05, 09:42 AM

Frequency As Follows : Channel 2 = 25
Channel 11=48
Channel 13=38
Channel 16=26
Channel 22=42
Channel 53=43
Channel 4=51

MHD1080

10-06-05, 09:46 AM

Also What Would Be The Beam For Just One Cm4221

cagrigsby

10-06-05, 11:01 AM

I have a question for you guys. I plan to put my first antenna on my roof. It is new construction. The antenna is going on the side of the house where the utilities are not located. Do I run a grounding wire all the way across the house to those grounds or can I go into the basement in the same hole I'm going to drill for the antenna coax cable and attach to a water pipe in the basement which would be on the side where the electrical and CATV boxes are not. Now there is a seperate box on the side of the house where the antenna is going for a 220 volt hot tub service, is there something there I can use?

Also, what do I attach the coax and grounding wire to the house with on the drop down, I have vinyl siding and soffits.

Thanks,
Chuck Grigsby
Champaign, IL

greywolf

10-06-05, 11:31 AM

First, always check your local building codes as they may differ from the NEC. That's also a good time to see if there is an acceptable ground point at the tub site.

That being said, the latest NEC requirement is that if a metal water pipe is used to ground an antenna, the connection must be made within 5ft of the entry of the pipe into the building and the pipe must also be grounded to the main building ground, usually at the electrical panel, within the same 5ft.

If your building department does not okay a spot in the tub area, I'd sink an 8ft grounding rod in the area and run a 10ga copper or better grounding wire from the antenna mast to the rod. A lightning arrestor or grounding block near where the coax enters the building would then also be grounded to the rod. If you are permitted a grounding point at the tub use that instead of the rod.

If you do sink a new grounding rod it is critical that that rod be bonded to the main house ground by a 6ga or better copper wire. That wire can run around the building or through it. The NEC defines the main house ground as:

(a)The building or structure electrode system as covered in 250-50.
(b)The grounded interior metal water piping system as covered in 250-104 (a).
(c)The power service accessible means external to enclosures as covered in Section 250-92 (b).
(d)The metallic power service raceway.
(e)The service equipment enclosure, or
(f)The grounding electrode conductor or the grounding electrode conductor metal enclosures

Probably the best way to run cable on vinyl siding is with metal clips that attach to the siding with short screws. Stainless steel screws are a good idea. http://www.mjsales.net/cat2.asp?this_Cat1ID=263&cat2ID=18 is one site that will picture such clips. Cable ties are good for running the ground wire with the coax.

deconvolver

10-06-05, 12:40 PM

Also What Would Be The Beam For Just One Cm4221
Check the 4225 beamwidths here:
http://www.starkelectronic.com/cmg5.htm
For channel 52 it is 44 degrees wide at the 3 dB down point. So you should be able to go +/- 11 degrees with minimal loss.

holl_ands

10-06-05, 04:22 PM

Db8 Is Suppose To Have A 90 Degree Beam Unlike The Cm4228 Which Is Only 10 To 15 Degrees

Just to clarify: the CM4225, CM4221 and CM3021 are all 4-Bay Bowties with Reflector Screens.
The Stark chart also shows the CM4228 8-Bay antenna.

All 8-Bay antennas will cover your fairly narrow spread of transmitter directions (301 to 315 deg is only 14 degrees).
But the beamwidths become narrower for the higher channel numbers.
You would need to align it very accurately, and periodically recheck alignment.
A strong wind could misalign the antenna, with only a few degrees of "margin".
Hence, you might want to use a rotator.

Click on CM4228 and PR8800 to see the antenna patterns calculated via NEC Simulations:
http://www.hdtvprimer.com/ANTENNAS/comparing.html
Unfortunately, the A-D DB-8 was not simulated, but I would expect it to have nearly the same beamwidth
for the main lobe and probably a somewhat different pattern for the sidelobes.

I posted a summary of DTV ANTENNA specs (Gain, Beamwidth, F/B Ratios), as well as comparison to NEC Simulations
and actual On-Air measurements at the end of this short thread:
http://hdtv.forsandiego.com/messages/1/2846.html?1126998999
Unfortunately, Antennas Direct choses to publish only a very limited set of ill-defined specs (Q: dBd or dBi???).
And I didn't see them publish ANY beamwidth claims for the DB-8 on their website.

holl_ands

10-06-05, 05:07 PM

What kind of work would I need to do? :) Are there any sites around that have instructions? A quick Google search only turned up things about antenna theory/physics, rather than actually building something...

I hope you saw my recent posts re DIY TV antennas:
http://www.avsforum.com/avs-vb/showthread.php?p=6205731&highlight=DIY#post6205731
http://www.avsforum.com/avs-vb/showthread.php?p=6213804&highlight=DIY#post6213804
http://www.avsforum.com/avs-vb/showthread.php?p=6250314&highlight=DIY#post6250314

An LPDA has the advantages of being able to cover the entire band of interest,
good VSWR, easy to use size calculator and not too hard to construct for attic use.
Making it rugged enough for outdoor use may be difficult for a first time DIY'er.
Unfortunately the Gain isn't very good and drops off for higher frequencies, when
you need it most to counteract propagation loss.

On the other hand, a high gain Yagi only has one driven element (unlike the LPDA)
and all the other elements are simple "sticks'. So it isn't too hard to build for both
attic and outdoor use. "Only" drawback is that the "standard" designs have a
very narrow bandwidth, covering only a few UHF channels.
But perhaps you could target one or two Yagis for some difficult channels and
combine it with another broadband antenna using a C-M Jointenna.

If you want to go beyond the standard designs, you will have to become an antenna designer and learn NEC.

The ARRL Handbook covers many antenna designs with details on construction,
however, only a few of them are for VHF/UHF bands.
But you will learn the basic techniques and can readily rescale the dimensions for ANY frequency of interest.

When you are done will you save any money?
Probably not, when you can buy high gain wide-band Yagi's, and CM4228 for $50 + shipping.

holl_ands

10-06-05, 06:23 PM

I just checked and it's the Radio Shack 15-1113B. It's from '96, but I found the manual at the RS site. The manual's specs "say" the gain is adjustable between 15-25dB and the noise figure is 6dB.

BTW, there's nearly 50' of old RG-59 from '96 with "twist-on" connectors after the amplifier. I think that looses ~3dB @ 700MHz. There's also a 3-way splitter that I tried removing with no change at all. I don't think there's any problem with the stuff after the amp, as I connected a receiver where the amp would be (so the amp was out of the loop), and had the same result as going the whole distance without the amp -- only 4 and 46 came in I believe.

The first Preamp dominates in determining overall sensitivity.
And any loss between it and the antenna will directly degrade the sensitivity.

I did a "what-if" exercise using my DTV_FADE_MARGIN_CALC_EXAMPLE spread sheet and found that
if you connect a CM7777 (or equal) Preamp directly to the antenna, the sensitivity (i.e. Fade Margin) should improve by over 10 dB.
Some of this is due to the Noise Figure being 3.8 dB better.
Some of this is due to moving the 2.5 dB loss in the RG-6 so that it is after the Preamp, thereby improving the Cascade Noise Figure.
I also assigned an additional 2 dB of loss to the RG-6 preceeding the R-S Preamp, due to sensitivity degradation
caused by antenna/Preamp VSWR mismatch, as was explained in the spread sheet:
http://hdtv.forsandiego.com/messages/1/2846.html?1126998999

holl_ands

10-06-05, 07:32 PM

Thanks for the reply Bob. :) Here's my station info:

Channel Direction Miles ERP (kW)
KTVI 2 (43) 105.5 43.1 1000
KMOV 4 (56) 104.6 47.1 1000
KSDK 5 (35) 101.9 44.7 838
KETC 9 (39) 110.7 43.0 125
KPLR 11 (26) 101.4 45.0 1000
KDNL 30 (31) 100.8 44.7 1000
WRBU 46 (47) 121.5 41.6 109

My antenna is at ~102 degrees. (It was at about 80 since '96 till I re-aimed a couple weeks ago, before I got the DTV receiver.) The side of the house is at ~75 degrees; so, the antenna is around 27 degrees to the right of that in the attic. The signal is coming through the [relatively steep] roof (1/2", I assume, plywood + asphalt shingles) at a lower angle than it would through the side wall (which would be closer to perpendicular, if that matters). I can't aim through the wall because of the antenna length (I think it's the 120", rated for 120/90mi VHF/UHF), the angle, and limited width (front to back of house) up there, which is basically all used now. It's in the second story attic, so about 20' off the ground. I just raised the front of it yesterday almost 3' I guess, so it's aimed upward ~10-15 degrees. Does that hurt? Well, it didn't help much anyway, though I thought it did at first last night...

Now for my channels... I don't think I'm overloaded. As far as analog channels go, VHF channels 2-11 come in about as well as expected. Before moving the antenna from the ~80 degree position, channel 9 had rolling horizontal bars, and 11 had pretty bad snow (its analog transmitter is in a different position than the digital one). Now 9 is great, and 11 only has minor/light snow. Channel 30 has always been the worst, and it's the best it's been now, with moderate snow. The picture is clear "enough" that you could watch a program and see what's going on OK, to give you an idea. It's 2190kW analog. Channel 46 looks like satellite from 20' away (5000kW). Other than very minor noise/static (2-9) or snow (11, 30) there are no other analog problems like ghosting, bars, etc.

The best digital channel is 4. It's mostly fine, worst signal is ~60% and goes as high as 90 after midnight; only rare minor breakups. 46 is next, mostly fine. 2 and 5: about the same -- signal jumping around below 50% during the day, into the 60s easily at night and basically as stable then as 4. 11 and 30 are the ones I'm having trouble with. They don't go higher than 40% during the day, even down to 0 every few seconds and don't come in. They're in the 50s at night (couple hours after sunset), but have too much breakup to be watchable. Sometimes they'll be fine for a couple minutes. I can't get channel 9 at all, but I didn't necessarily expect to (I'd LIKE to however). It jumps from 0 to ~30% in 1 or 2 second intervals. One time last week during late night/early morning, it did get into the high 40s for me to see mostly a full picture for a short time.

It sure seems weird that I get 46 so well at 1/9 the power. :confused: I could probably aim another UHF antenna through the side wall if that would be better. But like I said/asked, I don't know if I can make my own. :)

Using the info above, I navigated to your location using antennaweb.org.
Appears to be zipcode 63357, about 5 mi NW of Marthasville, MO, in general vicinity of State Hwy CC and State Hwy 47.
I was surprised to see only two (purple) stations pop up for the same ranges and bearings as above.
However, small displacements resulted in big changes in antennaweb.

GoogleEarth appears to show you in a narrow valley, although this may be incorrect.
If you are in this valley, at your extended range, you should seriously consider moving the antenna to the roof.

If you want to remain in the attic, you might want to investigate different locations in the attic using a smaller
UHF-only antenna, such as the CM-4221 4-Bay or high gain CM-4228 8-Bay.
If this helps, you might want to combine it with the R-S Combi, using the low loss C-M 0549 UHF-VHF/FM Antenna Joiner,
so the R-S becomes a VHF/FM only antenna.

The combination of the valley and the attic will make for a very murky multipath soup,
best explaining why some stations work and others do not.

Using the LAT/LOG guestimate from GoogleEarth, I used www.2150.com/broadcast to see
if there were any nearby transmitters that might desensitize a Preamp.
There were three low power stations about 25 miles away, so they shouldn't be a problem.

bernieoc

10-06-05, 08:38 PM

deconvolver

10-06-05, 09:02 PM

Which is the lessor of two evils ?
1 Antenna on roof facing directly into nearby trees.
2 Antenna in attic missing nearby trees.
I now have large RS antenna on roof with ch3, 18, 30 at 47 miles 270 deg
and ch34, 20 at 23 miles 300 deg.
my reception is close to good on all - but have weather, wind, season problems.
I am thinking a better uhf (4228) and a low vhf (y5-26) in the attic missing trees.
Or should I upgrade my outdoor (hopefully without a rotator)
If you check earlier posts about attic losses you will see that huge losses are typical. In an attic an antenna will usually be negatively influenced by signal reflections from wiring and plumbing and anything else metal that is nearby or forward of it. There is also the possibility of almost complete shielding from things like metal foil that could be in the insulation's vapor barrier for instance. If you aim through a roof or anything that could be wet then during rainstorms there could be additional loss. There is some small possibility that If you were able to aim directly through an exterior wall with no metal anywhere except well behind (NOT in the floor underneath) the antenna then you might get OK results.

mrgreen4242

10-06-05, 10:33 PM

Hi everyone... I've read through a lot of this thread in the last couple days, but it is so long that I'm not sure anyone could read it all, at this point... Anyways, I'm in a bit of a dilemma... I live on the third floor of an apartment building. I have a balcony, but it's on the north side of the building. According to antennaweb.org all my digital transmitters are to my south, southeast, and southwest (figures... everything is south, I'd have just got a dish if I was facing that way!) The stations I am mostly interested in are to the south. (I'll post the antennaweb results at the bottom).

Anyways, being in an apartment I am going to have to go with an indoor antenna. There are no tall buildings in my area, and it's pretty flat from here to the antenna's. There is a small patch of tall trees on the north side of the building, not a forrest, but also not just one tree.

UHF is my only concern at this point, I will have moved by the time I need to worry about any of these channels moving back to VHF. I am looking at either a Silver Sensor or a DB-2 antenna. My question is, based on these factors (indoors, third floor, no windows to the south) and my antennaweb results, what are the odds of me getting any decent reception, which antenna would be best for me, and will an amp or pre-amp help me at all?

(These are the results from antennaweb, zip code 48837, saying no to "the question", and selecting "multiple story" from the list. I've filtered for only digital stations and also removed the furthest away stations)

* yellow - uhf WZPX-DT 43.1 i BATTLE CREEK MI 260° 16.7 44
* yellow - uhf WLNS-DT 6.1 CBS LANSING MI 107° 19.3 59
* yellow - uhf WSYM-DT 47.1 FOX LANSING MI 171° 19.8 38
* yellow - uhf WLAJ-DT 53.1 ABC LANSING MI 158° 25.2 51
* green - uhf WHTV-DT 34 UPN JACKSON MI TBD 158° 25.2 34
* red - uhf WILX-DT 10.1 NBC ONONDAGA MI 162° 22.7 57
* blue - uhf WKAR-DT 23.1 PBS EAST LANSING MI 105° 17.3 55

Thanks a ton... I'm working on getting a cheap OTA tuner from the Radio Shack clearance right now, I'm sure I will use it eventually, but hopefully you folks can get me started on the right path.

PS I was looking at my building earlier and noticed that there is a huge antenna on top of it. I have no idea how to get a signal from it, though. I assume that it was wired up there before the building was connected to the cable system... I'm going to inquire about it tomorrow, but since there is only one incoming RF jack in my place I assume everything has been rerouted to the cable interface box, which I need to stay on for internet service. :(

DR_LaRRY_PEpPeR

10-07-05, 07:26 AM

holl_ands, thanks for your info/time/answers/etc! Sorry, now that you mentioned your posts about DIY antennas, I do vaguely remember seeing them after I joined and wasn't really paying attention. :o A couple links in your posts helped, and I think I better try to make what I have work, or just buy something else if necessary. Also, thanks for the pre-amp calculations, I'll definitely keep that in mind!

Using the info above, I navigated to your location using antennaweb.org.
Appears to be zipcode 63357, about 5 mi NW of Marthasville, MO, in general vicinity of State Hwy CC and State Hwy 47.

You sure did! :eek: Haha, I knew that could be done though... I was going to send you my actual coordinates, but it looks like you have PM's disabled. I'll just post them here and can remove them in a few days or something. From Google Maps/Satellite: <removed>. I tried to use Google Earth after you mentioned it, but it just goes gray when it zooms in. :( I guess my video card is too old (tried on Voodoo3, V5 in another system that I can't try now), although I can see the Earth when it's zoomed out far enough...

I was surprised to see only two (purple) stations pop up for the same ranges and bearings as above.
However, small displacements resulted in big changes in antennaweb.

They are all purple when set to my location (and no digitals). Yeah, the results do change a lot when moved like only 1/4 mile.

GoogleEarth appears to show you in a narrow valley, although this may be incorrect.

Does it if you use my actual location? I can't tell for sure from here like I said earlier, I just know there are hills in the opposite direction of the stations.

If you are in this valley, at your extended range, you should seriously consider moving the antenna to the roof.

If you want to remain in the attic, you might want to investigate different locations in the attic using a smaller
UHF-only antenna, ...

The combination of the valley and the attic will make for a very murky multipath soup,
best explaining why some stations work and others do not.

I really don't want to bother moving it to the roof, especially because we're supposed to be moving sometime. :) If I'm in a valley (very deep?), what do you think about lower power WRBU-46 coming in better than half the others (basically), and it's almost 20 degrees off-axis (which loses a few dB, correct?)? If you can tell with Google Earth, does it look like there's a lot better path, terrain- or obstruction-wise, between me and the 121 deg. direction vs. the 101-105 ones? But remember, KMOV-4 gets here from 104.6!

Otherwise, I'm wondering if there's a problem with the current attic position and something blocking or interfering with signals. Because of maneuverability, the antenna hasn't been moved other than raising the front. It's hard to explain, but it's at the east end of the attic now, almost aiming at where aluminum fascia is outside. But that only goes down a couple feet from the peak on the south side (there are "staggered" peaks), so I think it's to the left of where the antenna is pointing (but probably within 2-3' of the antenna iself). I'm not sure what kind of flashing, etc. there might be where the fascia meets roof again or how I'm aimed in regards to that. deconvolver just mentioned "metal that is nearby," so I wonder... and obviously the 121 deg. signal would "clear" any of this more -- only coming through the roof, I think.

I've been using the Triangle Angle Calculator (www.csgnetwork.com/righttricalc.html) for my angle measurements, and since I was wondering if it's a problem that the 101 deg. signal comes through the roof at a lower angle, I tried to calculate how much roof the signals pass through from the different directions. I said the side of the house is at ~75 deg., so the 101 signal comes through the the roof @ 26 degrees. So with a 1/2" of roof, horizontally the signal would go through ~1.1". The 121 is 46 deg. through the roof, so 0.7". Then, I think the roof has an 8/12 pitch, so ~34 degrees, meaning 0.9" to go through on the other axis (?). If my calculating is correct (who knows!!), combining them gives ~1.4" and 1.1" to pass through for 101 and 121 degree signals, respectively. That difference probably doesn't affect much, does it?

BTW, you mentioned "multipath soup," but I see absolutely NO ghosting or anything on the analog channels.

nsayer

10-07-05, 02:00 PM

holl_ands

10-07-05, 03:53 PM

I need to install a preamp, but the problem is I have a BMS-58 mounted outdoors, which does not pass DC to the antenna input. So I have a couple questions:

1. How forgiving are typical preamps about voltage variation? The best preamp I have tried (and I've tried half a dozen) has turned out to be the Terk BIA-20. It uses satellite receiver voltage, which can be either 12 or 18 volts. The BMS-58 uses 24 volts. If I were to feed the 24 volts to the BIA-20, would it still work?

2. Where can I get an outdoor-safe power injector? One way or another I'm going to need to input the power after the BIA-20, and it's outdoors, so it needs to be outdoor safe.

3. Would it work to use two power injectors - one on the antenna input side of the BMS-58 and the other on one of the outputs and simply connect the DC "inputs" on both with a wire? Would this make an acceptable DC bypass without inducing too much loss?
The spec sheet for the Terk BMS-58 Multiswitch (TV+4 LNBs to 8 Outputs) says that the TV input goes
through a built in Low Noise Preamp before going to the 8 outputs, with a typical insertion loss of 4.5 dB.
It also says "it features a DC pass capability allowing it to be used with amplified antennas that require DC power via a coaxial cable".

So, it is designed to feed DC power to a mast head Preamp.
Unfortunately, it doesn't say what voltage level, so grab a meter and measure it to make sure what you're dealing with.

FYI: If you decide to go with one of the well known Preamps (C-M and W-G),
then make sure the BMS-58 output voltage is compatible with the Preamp.
And yes, you could use a DC Power Insertion Module between the BMS-58 and a mast head Preamp, just doublecheck connections.
DC goes to the mast head Preamp and a blocking capacitor prevents DC from one device from being applied to the other (and vice versa).

I've seen some Preamps that use a wall-plug AC/DC power converter that can be mounted indoors and a
separate Power Insertion "TEE" Module that can be mounted outside since it operates at low level DC voltage.

VERY IMPORTANT: When you cascade Preamps, the high level signal from the mast head Preamp WILL DESENSITIZE
if not OVERLOAD the low noise Preamp in the BMS-58. Insert a R-S Variable RF Attenuator on the BMS-58's TV input.

nsayer

10-07-05, 04:25 PM

The spec sheet for the Terk BMS-58 Multiswitch (TV+4 LNBs to 8 Outputs) says that the TV input goes
through a built in Low Noise Preamp before going to the 8 outputs, with a typical insertion loss of 4.5 dB.
It also says "it features a DC pass capability allowing it to be used with amplified antennas that require DC power via a coaxial cable".

Lies.

Unfortunately, it doesn't say what voltage level, so grab a meter and measure it to make sure what you're dealing with.

Turns out that voltage is 0. :)

I even e-mailed their tech support department and they confirmed that it won't supply or pass DC on the antenna input.

Don't feel bad - I thought I saw this on the spec sheet as well. I think the amplifier amplifies the DBS portion of the signal, since the insertion loss on the satellite side is unity (0 db). 4.5 db on the antenna side would be about right, it seems to me, for a simple 8 way splitter.

greywolf

10-07-05, 06:19 PM

It was established here a while back that there is no power at the antenna input. There is some amplification of the Ant input though as passive splitters would lose ~11db at any output.

cpcat

10-07-05, 06:26 PM

nsayer

10-07-05, 06:42 PM

Sounds like to me your best option is a separate downlead for the antenna and to bypass the multiswitch altogether.

Yeah, except that I'd need to split it at least 4 ways and run 4 more pieces of coax under the house to spots where coax is already going. I am highly motivated to make this work.

cpcat

10-07-05, 07:12 PM

Yeah, except that I'd need to split it at least 4 ways and run 4 more pieces of coax under the house to spots where coax is already going. I am highly motivated to make this work.

You could use the separate downlead simply to inject the power through a power injector or a hi-lo separator (if you don't need channels 2-6), then you wouldn't need to run anymore line, but you'd still have the signal passing through the multiswitch.

nsayer

10-07-05, 07:20 PM

You could use the separate downlead simply to inject the power through a power injector or a hi-lo separator (if you don't need channels 2-6), then you wouldn't need to run anymore line, but you'd still have the signal passing through the multiswitch.

I actually am thinking of something close.

I already have a coax supplying +24VDC to the BMS-58. I could make a custom T, possibly with an additional voltage regulator, to break out that voltage to an injector on the antenna side of the BMS-58.

But that begs the questions of the insertion loss of a power injector, and where to get "bare" power injectors.

cpcat

10-07-05, 07:27 PM

I actually am thinking of something close.

I already have a coax supplying +24VDC to the BMS-58. I could make a custom T, possibly with an additional voltage regulator, to break out that voltage to an injector on the antenna side of the BMS-58.

But that begs the questions of the insertion loss of a power injector, and where to get "bare" power injectors.

Run the separate downlead from somewhere dry inside with AC power access. That will supply DC to the power pass port (SAT) of a TV/SAT diplexer on the mast and then on to the amp. Then bring the signal out from the TV out (now amplified) port back to the ANT IN on the multiswitch.

TV/SAT diplexer with DC pass on SAT port: http://www.picomacom.com/specs/pico/C/C24.pdf

You could also use the HLSJ the same way with the DC going through the LOW port but you would only end up with channels 7 and above. This actually can be an advantage if you want to get rid of FM and lo band.

holl_ands

10-07-05, 09:41 PM

Lies.

Turns out that voltage is 0. :)

I even e-mailed their tech support department and they confirmed that it won't supply or pass DC on the antenna input.

Don't feel bad - I thought I saw this on the spec sheet as well. I think the amplifier amplifies the DBS portion of the signal, since the insertion loss on the satellite side is unity (0 db). 4.5 db on the antenna side would be about right, it seems to me, for a simple 8 way splitter.

In order to split the TV signal 8 ways, the signal would go through a TV Preamp, then a 2-way splitter (3.5 to 4 dB loss)
and then each splitter port would go through a 4-way splitter (7 to 8 dB loss) and then 8 Diplexers (0.5 dB) to combine
it with each of the 8 outputs. That's a total loss of about 12 dB.
So the TV Preamp inside the BMS58 must only have a gain of about 8 dB.

If you are going to jury rig your own 24 VDC bypass, you would also need to use some inductors to block
the RF signal on an ACTIVE Multiswitch output from being shorted out in the bypass itself and a zener to drop the voltage.
If you are puzzled by this, you shouldn't design a 24 VDB bypass.

I suppose it would be possible to fabricate your own power insertion "TEE",
using a small WEATHERPROOF box with
three F-connectors and feeding the "ANTENNA" output of a W-G or C-M in-line type Power Module to the "TEE".
A capacitor should be inside the "TEE" box to block DC power to the BMS58 and the DC input
should go through an inductor before it is connected to the coax signal.

======================================================
Instead, look at the following Preamp that includes a separate "TEE" power insertion module that can be
used outdoors, with the wall-mount AC/DC power module inside:
http://www.solidsignal.com/prod_display.asp?main_cat=304&CAT=&PROD=CM3039

cpcat

10-07-05, 10:09 PM

======================================================
Instead, look at the following Preamp that includes a separate "TEE" power insertion module that can be
used outdoors, with the wall-mount AC/DC power module inside:
http://www.solidsignal.com/prod_display.asp?main_cat=304&CAT=&PROD=CM3039

This is just the el cheapo CM preamp. There is nothing different other than the DC is supplied via a wall-wart instead of the beefier PS on the upper range models. The TEE still must go inside and the DC goes up the coax as usual.

FYI the CM preamps will operate fine on DC from +12 to +24 Volts.

insurancepi

10-08-05, 12:42 PM

have learned the following, that I can pick up 5 OTA channels. In addition, the compass Orientation from my house only varies from 240 degrees to 245 degrees with each channel. Also these channels are all UHF and the distance from the broadcast sites to my house range from 18 to 28 miles. My question is this, I was thinking of putting an antenna in my attic, will a directional antenna work and what size should I get, or will in indoor antenna work. I am in Jackson, MS and will have to purchase the antenna at Radio Shack or Best Buy, Circuit City. Please give my you opinions. Thanks.

deconvolver

10-08-05, 01:40 PM

PhracturedBlue

10-08-05, 03:28 PM

Just a followup. I just installed a CM4228 (to replace to 3016) as recommended here.
When pointed at the transmitters, all signals improved, and I get a very good signals on all channels except 27 (KOPB) which is the one I really want.
When I reversed the antenna, and point away fro the transmitters, KOPB gets a decent lock (just like it did with the 3016).

The 4228 gave me about 2db and 20% signal-quality improvemnt for KOPB when pointing away from the transmitters, but all other channels are worse than they were with the 3016.

When pointing at the transmitters, all channels are better, (about 20-30% signal quality, 2-3db SNR) but I still can't get a solid lock on KOPB (as I mentioned above)

If I only had one receiver, an antenna-rotor would prbably be the solution, but that won't work with my (planned) dual receivers.

I ordered a CM7775 as well, and it should come in next week, so we'll see how things look after I install it.
Also, my coax is currently ~40ft of RG-59, which I'll be replacing with RG-6 once the pre-amp comes in. As my signal-strength is at 100% on all channels now, i may need an attenuator as well

holl_ands

10-08-05, 06:30 PM

I tried to use Google Earth after you mentioned it, but it just goes gray when it zooms in. :( I guess my video card is too old (tried on Voodoo3, V5 in another system that I can't try now), although I can see the Earth when it's zoomed out far enough...

[GoogleEarth is also a big memory hog and really needs to be on a fast connection.]

They are all purple when set to my location (and no digitals). Yeah, the results do change a lot when moved like only 1/4 mile.

[Your revised location pulls up the same antennaweb results now...give or take a few hundred yards inaccuracy inherent in both antennweb and GoogleEarth.]

Does it if you use my actual location? I can't tell for sure from here like I said earlier, I just know there are hills in the opposite direction of the stations.

[Although you still have hills behind you that can cause a backscatter bounce,
you aren't buried in a valley like I thought you were earlier.
Much better....esp. since you do not see multipath on analog channels.]

I really don't want to bother moving it to the roof, especially because we're supposed to be moving sometime. :) If I'm in a valley (very deep?), what do you think about lower power WRBU-46 coming in better than half the others (basically), and it's almost 20 degrees off-axis (which loses a few dB, correct?)? If you can tell with Google Earth, does it look like there's a lot better path, terrain- or obstruction-wise, between me and the 121 deg. direction vs. the 101-105 ones? But remember, KMOV-4 gets here from 104.6!

[The 101-105 arrival direction passes over a hill that is closer to you than the 120 direction, which would cause some signal strength difference.
However, different frequency signals will always have different strong and weak areas within your attic....or even outdoors.]

Otherwise, I'm wondering if there's a problem with the current attic position and something blocking or interfering with signals. Because of maneuverability, the antenna hasn't been moved other than raising the front. It's hard to explain, but it's at the east end of the attic now, almost aiming at where aluminum fascia is outside. But that only goes down a couple feet from the peak on the south side (there are "staggered" peaks), so I think it's to the left of where the antenna is pointing (but probably within 2-3' of the antenna iself). I'm not sure what kind of flashing, etc. there might be where the fascia meets roof again or how I'm aimed in regards to that. deconvolver just mentioned "metal that is nearby," so I wonder... and obviously the 121 deg. signal would "clear" any of this more -- only coming through the roof, I think.

I've been using the Triangle Angle Calculator (www.csgnetwork.com/righttricalc.html) for my angle measurements, and since I was wondering if it's a problem that the 101 deg. signal comes through the roof at a lower angle, I tried to calculate how much roof the signals pass through from the different directions. I said the side of the house is at ~75 deg., so the 101 signal comes through the the roof @ 26 degrees. So with a 1/2" of roof, horizontally the signal would go through ~1.1". The 121 is 46 deg. through the roof, so 0.7". Then, I think the roof has an 8/12 pitch, so ~34 degrees, meaning 0.9" to go through on the other axis (?). If my calculating is correct (who knows!!), combining them gives ~1.4" and 1.1" to pass through for 101 and 121 degree signals, respectively. That difference probably doesn't affect much, does it?

BTW, you mentioned "multipath soup," but I see absolutely NO ghosting or anything on the analog channels.

[Hunt and peck is the only way I know to find a "sweet" spot.
Avoid "looking" through metal and electrical wiring as much as possible,
which may require raising or lowering the antenna.

deconvolver

10-08-05, 06:34 PM

mgtr

10-10-05, 02:04 PM

insurancepi-
I have a somewhat similar circumstance, and found that a CM 4228 mounted upside down from the highest point in the attic works extremely well. Bear in mind that a preamp might be required if you run an extraordinary amount of RG-6. In my setup, I have about 50 feet and have not needed the preamp.

deconvolver

10-10-05, 09:32 PM

Thanks to www.hdtvprimer.com models of many popular antennas including the Channelmaster 4228 are available for analysis. On the hdtvprimer web site that antenna is modelled as having one continuous screen. To see the effect of having one versus two separate screens I changed the model to separate the screens by 0.2 inches. I have enclosed plots of the resulting horizontal beampatterns for VHF channels 8, 10, and 12. It is interesting that splitting the screen yields worse performance for channels 10 and 12 but better performance for channel 8. The antenna impedance was also affected by splitting the screen. The original values for the three channels were respectively: 12.5-j145, 122-j6.5, and 153+j273. With the split screen the impedances were: 12.7-j159, 37.1-j10, and 117+j242. So we can see that the net gain will be much worse for channel 10 with a split screen than a continuous one.

kflorek

10-10-05, 10:04 PM

cagrigsby,

> Do I run a grounding wire all the way across the house to those grounds...?

If some one decides to sink a ground rod, here is a tip that I ran across years ago, as I remember it, when I was into shortwave listening, which also uses antennas and grounds.

Driving a 5/8 inch rod 8 feet into the ground with a hammer can be difficult. Instead, you can have water do the work. Get a 1/2 inch copper pipe (it is 5/8 outside diameter.) With a hose clamp, clamp a few feet of 5/8 water hose remnant to the pipe and attach that to your water hose with a cheap plastic shutoff so you can control the water. Shove the pipe a foot or so into the ground, and put the water on just a little. You don't want a flood or gusher when you are that near surface. Later, putting the water on full for a while will get you past spots where the resistance stops you. You can push the pipe easily 8 or 12 feet into the ground.

If you hit a rock, you are probably out of luck whether you use a hammer or water drilling. But try to extract a rod hammered deep in the ground! You can get the water-drilling pipe out about as easily as it went in.

Now here's my experience. My 1957-built house uses a water pipe for the service entrance ground, which pipe runs about 40 feet before it gets to the outside. That does not seem like such a great idea with respect to lightning. I bought an 8 foot ground rod from Home Depot ($15), just because that seems to be what is generally used. I believe pipe also complies with NEC, although I don't know the details. I shoved the rod about 2 1/2 feet into the ground by just pushing and pulling the rod up and down. The dirt, or whatever, suddenly got super hard, making me chicken-out about hammering, so I switched to water drilling. I happended to have everything I needed, except for a metal pipe. All I had was 9 feet of left-over 1/2 inch CPVC water pipe. This plastic pipe is not much more rigid than a noodle. But it worked fine, like pushing through butter. You just have to push firmly on it close to ground, and take care that it doesn't flex excessively, and don't overdo the force. Putting the water on full for a minute gets you past the tough spots. No water comes up after you get it 2 feet into the ground. At 6 1/2 feet there was a layer which water drilling didn't work on at all. When I took out the pipe and pushed the ground rod to the bottom, it felt like it was grinding on small stones when I twisted and shoved the rod. Hammering got the rod down to ground level, at about a 1/4 inch per blow. At first I didn't think it was moving.

Because of a personal experience, I take grounding more seriously than I generally take warnings. In my shortwave days, I used to have a 30 foot high home-made antenna on the roof. You are supposed to ground the antenna when not in use, which I did by moving the antenna lead from the radio to a ground wire with an allgator clip. I was awakened about 3 AM from a dead sleep one night by a loud snapping noise. I glanced over in the black to see a spark in time to the snapping. I ran from the room in terror. I thought it was a discharge such as is sometimes described preceding a lightening strike. When the popping stopped after a few minutes, I went back and turned on the light. What I saw made my blood run cold: The space between the alligator clip (that I negelected to attach) and the ground lead was about 6 inches. I still can't believe a spark could jump a gap like that but I don't know what else the explanation could be. BTW, it was not in a rain storm, but a very windy, dry, ten-degree night in winter, and there was no snow except for sparse crystals blowing like dust. What I saw was probably atmospheric static and not lightning. It did not cause any damage, other than to my psyche. But I know from personal experience about natural electricity at scarey levels.

nsayer

10-10-05, 10:41 PM

I believe I've figured out the root of my problems. The BMS-58 (at least, the one I have) does not play well with diplexers. The minute you apply a polarity selection voltage to one of the drops, the <900 MHz signal drops significantly. I've found that the only way to get along with it is to run direct drops for satellite or DTV tuners.

I suppose another option is to replace the BMS-58, but I haven't seen any others suitable for outdoor installation.

greywolf

10-10-05, 11:53 PM

It's more likely the diplexers are at fault. They are cheaper to replace too. Hook up a line directly to the receiver instead of through a diplexer and I'll bet you have no trouble with the OTA signals. I've read here that Spaun diplexers are the only ones that do well in testing but they are pricey.

MHD1080

10-11-05, 10:44 AM

I Bought The Db-8 And Split It Into 2 Seperate Antenna's- If I Point Them In 2 Different Direction And Use There Combiner Do I Need To Have Equal Lengths Of Wire From Each Antenna To The Combiner? And How Far Apart Do They Need To Be So They Don't Cause Multi Pathing?

greywolf

10-11-05, 11:15 AM

The act of of pointing them in different direction creates multipath problems. Equal length leads and spacing are important for matched antennas pointing in the same direction.

There is a lot of luck involved in getting different direction setups to work. Jointennas which are tuned to specific frequencies can help by rejecting channel groups which cause problems while passing desired ranges but a lot depends on the realtionships between the channel sets in the two directions. It's rarely a trivial job and more often an impossible task to get every channel desired. A/B switches and rotators are good solutions in live viewing situations but PVRs and recording in absentia don't allow those solutions.

If you post your location and what channels you are trying to pick up from what directions, there are people here who are great at figuring this stuff out who may be able to render more specific aid.

newsposter

10-11-05, 02:25 PM

Ken,you are sooooo right.Thanks for heading up this thread.I'll start it out with one of the best setups for UHF reception...and I've tried 'em all<g>

Lots of pics and nice links for valuable info.

http://community-2.webtv.net/GregBarker/CurrentUHFTower/

I believe post 3 needs an updated link

http://community-2.webtv.net/GregBarker/NewTowerAntennas/index.html

us newbies get lost!

newsposter

10-11-05, 02:34 PM

I've been toying with my DB8 while my wife is inside telling me the signals. I can get channel 26 (Philly) in the 80s signal wise but none of the other ones come in more than 60s usually and mostly are in the 30s. I know this can't be used as my permanent mounting position but is it just a weaker amount of power from the other stations or does something have to do with the actual channel numbers? In other words, will channel 26 come in inherentily better than 64 and 67 because of it's frequency?

Also I have lots of problems with the lower signals not being equal on both tuners but assume with a stronger signal that will resolve on my HDtivo.

and how do you guys aim? do you find a mounting spot then try to tweak or do you carry the thing around on the pole (it's what i'm doing) and see what the signal is different places around your house? Seems you can't mount until you know you have a signal. Actually I am using my patio table with umbrella stand, works wonderfully for now.

Also, if all channels are at 130 (except fox at 128), shouldn't all the 130s come in while facing the same way? i've had to turn the antenna what i believe is more than a few degrees (probably an inch in distance) to get better signals on some of the stations. So that's what makes me wonder if the antennaweb thing isn't really accurate for me.

with all this rain i can't even attempt roof mounting but have had my antenna up about 8-12 ft via various methods over the past few days.

Also funny thing is, the strongest signal appears to come while directly facing some trees. I'm worried about mounting after leaves fall because I'd be in trouble in spring when they come back. So time is ticking to get a good signal permanently.

colofan

10-11-05, 03:33 PM

How much tilt up would a person typically need for a CM4228 with a station 50 miles away?

deconvolver

10-11-05, 04:12 PM

How much tilt up would a person typically need for a CM4228 with a station 50 miles away?
The 4228 should be aimed at the horizon.

cpcat

10-11-05, 04:51 PM

I believe post 3 needs an updated link

http://community-2.webtv.net/GregBarker/NewTowerAntennas/index.html

us newbies get lost!

Wow, I'm impressed there are still folks who are reading back that far.

GregB is my hero BTW. :)

TotallyPreWired

10-11-05, 07:27 PM

....Spacing will not help defeat multipath.
Opinions vary on that subject. Please see the 'Two Antenna Trick', it's here. (http://www.hdtvprimer.com/ANTENNAS/silver.html)

Anyway, that's not what brought me here. This is:
I'm in the(ongoing) process of updating my antenna system. The original system consisted of 2 antennas combined with a Join-Tenna. The main antenna is a Winegard 8200 and the 'sidearm' antenna is 1/2 the size pointing in an opposite direction. The 2 antennas connected directly to the Join-Tenna, and then it connected to a Winegard preamp, and into the house.

During testing we disconnected the 8200 and connected the lead to a CM 4228. That worked like a charm, and a station that I could not receive before locked right in. Fine. Since I really no longer needed the 'sidearm' antenna, we disconnected the Join-Tenna(figuring that might help), and we reconnected the 8200 directly to the preamp. From that point on, the 8200 has not performed as well, and the 4228 has been used in another testing situation(where it has never locked that station).

So, why would disconnecting the Join-Tenna cause the main antenna to perform worse:

Maybe one of the new cables was bad? Maybe, but I make up some pretty decent cables, so I doubt that...
There's a bad connection somewhere? That's possible, and it'll be checked...
Maybe the antenna connector was damaged? That's also possible.

Anyone got any other ideas/explainations? The antennas are on a short tower, and my climbing buddy is out of town, so any checking will have to wait.

Now the reason that the 4228 locked right on, could be atmosphere related, as the station is 53 miles away.
....jc

CEB II

10-11-05, 07:52 PM

Anyway, that's not what brought me here. This is:

So, why would disconnecting the Join-Tenna cause the main antenna to perform worse:

Maybe one of the new cables was bad? Maybe, but I make up some pretty decent cables, so I doubt that...
There's a bad connection somewhere? That's possible, and it'll be checked...
Maybe the antenna connector was damaged? That's also possible.

Anyone got any other ideas/explainations? The antennas are on a short tower, and my climbing buddy is out of town, so any checking will have to wait.

Now the reason that the 4228 locked right on, could be atmosphere related, as the station is 53 miles away.
....jc

Some variable other than the Join-Tenna changed and the 8200 is now getting multi-path signals and/or signal overload. Did the aiming direction of the 8200 change? Did the sideare antenna shield the 8200 from a given direction and now it has been removed? Just looking out side the box, nothing definitive here.

TotallyPreWired

10-11-05, 08:29 PM

Some variable other than the Join-Tenna changed and the 8200 is now getting multi-path signals and/or signal overload. Did the aiming direction of the 8200 change?
Undoubtedly. A few degrees at best. We tried many pointings to try to get back to what I had prior to the testing. The change has affected all channels, even our beloved KMGH(Denver area joke)!
Did the sideare antenna shield the 8200 from a given direction and now it has been removed?
The 'sidearm' is mounted at least 6' below the 8200, and it's still there, just not connected to anything.

The problem is that the antenna performed better prior to the changes. So, it boils down to a bad cable/connection, or the Join-Tenna had something to do with it. The next time we test, the 1st thing we'll be doing is hooking the the JT back up!
....jc

GW222

10-11-05, 10:56 PM

hello,

I just had an OTA antenna installed, in order to pull all the channels the D* guy said to buy an in line amplifier, I did, the Radio Shack 15-1170.

All the OTA channles now come really strong, but I lose several satellite(CNN, ESPN all HD) channels with the amplifier. Once removed all the sat channels return, worth pointing that I dont lose all just some of the channels, esp HD. It seems that it cannot lock to all the sats, I infer but not sure if it is or why.

Thoughts on this? Thanks, I have used the search fx but cannot find an answer.

holl_ands

10-12-05, 02:48 AM

AntAltMike

10-12-05, 05:39 AM

Is GW222 using a diplexer? If so, then it is blocking his LNB switching voltage and 22Kz tone. If another receiver is connected to his triple-LNB, that receiver is powering the LNB and it is still sending the Sat "A" (101 deg) odd transponders to his HDTV receiver.

If that is the problem, then he probably can remedy it by using a diplexer that passes DC on both legs. Channel Master and Terk (ugh!) both make them.

newsposter

10-12-05, 08:48 AM

newsposter

10-12-05, 08:54 AM

Wow, I'm impressed there are still folks who are reading back that far.

GregB is my hero BTW. :)

well I decided to start at page 1 but figured i'd skip a few after that because the info was so old.

newsposter

10-12-05, 10:42 AM

Now that this board led me to the fcc page, I see my problem first handed

26= 770kw
32=250
42= 305 I assume APP means they are applying for 1000?
54= 500
64=500
67=560

So I'd assume if they cranked up the power I'd be ok. However If i'm reading the page right, it appears only fox has an app in for 1000.

Ken H

10-12-05, 01:11 PM

Cross posted comments and replies deleted.

gadgetfreaky

10-12-05, 02:31 PM

K Rock XP

10-12-05, 03:49 PM

No, 7 and 10 are transmitted digitally on channels 8 and 9 (from the last column in your antennaweb results) so they are VHF-high. I'm sorry I continued the joking about VHF-low antennas because they aren't needed by almost anyone for digital TV. The 4228 8-bay is a not-too bad antenna for VHF-high; it should be much better for that than a 4221. If you mounted rabbit ears on your roof they would probably work for your VHF channels and the 4228 is as good as or better than rabbit ears so I expect that the 4228 would be OK. It is way more UHF antenna than you need though so you could go with a smaller UHF antenna plus a small VHF-high antenna instead if you think that looks better.

Hey guys i got the ANT. but something strange has happened. I only ordered one ant. and was only charged for one ANT. on my CC. but take a look i think they sent me 3 ant's unless it is a huge ant. whats your thoughts on it?

http://www.squadxp.com/news/ant1.jpg
http://www.squadxp.com/news/ant2.jpg
http://www.squadxp.com/news/ant3.jpg

K Rock XP

holl_ands

10-12-05, 04:00 PM

Somewhere there are two people wondering where their missing CM4228's might be.
Obviously, each one came in it's own box.

georget

10-12-05, 09:26 PM

What Would Jesus Do?

TotallyPreWired

10-12-05, 09:43 PM

What Would Jesus Do?
He'd prolly say: 'This sure beats grilling with a stick. I can just place the meat on this thing!'
....jc

K Rock XP

10-12-05, 10:01 PM

Somewhere there are two people wondering where their missing CM4228's might be.
Obviously, each one came in it's own box.

lol wondering if i should return them.

GW222

10-12-05, 10:55 PM

Thanks Mike and Newposter,

I have a diplexer at the receiver end, but also imagine there is one upstream on the roof that consolidates the OTA plus my three receivers only one of them is HD.

I looked ta the current dlpxr is a cheap RCA that D* install at hte receiver end, is this the one you refer to?

Thanks

cpcat

10-12-05, 10:57 PM

Please help... I'm losing credibility with a friend. I convinced him to switch from cable to DirecTV HD, and with the OTA he can't get ABC and CBS. He's in San Diego and according to www.antennaweb.org he is only 7.3 miles from those 2 stations. He's getting all the other ones, fox, nbc, at 19 miles away. The directv OTA antenna didn't get much, so we bought this at radio shack, http://www.radioshack.com/product.asp?catalog%5Fname=CTLG&category%5Fname=CTLG%5F003%5F001%5F002%5F000&product%5Fid=15%2D2160 a 40" boom. That didn't work so he go the 80" http://www.radioshack.com/product.asp?catalog%5Fname=CTLG&category%5Fname=CTLG%5F003%5F001%5F002%5F000&product%5Fid=15%2D2160 still no luck and these are supposed to have 70 mile ranges.

The problem is, that according to the antennaweb, the direction that the antenna needs to point to get ABC and CBS are at a hill as he sits at the bottom of it. The house is 2 stories and the hill is about another 40 feet higher than the house.

Will any antenna pick up these channels? Or does he have to have direct line of site and the hill is going to always block it..

Directv will not grant the waivers, and he's been declined 2 times.

the channelmaster 4228 or the DB8 look great, but he said if he bought either and they didn't work, he'd make me pay for it... ;)

Will an amplifier work? If so, I'm not that familiar with them, do they plug inside where the tv is, or outdoors where the antenna is. will this work? http://www.radioshack.com/product.asp?cookie%5Ftest=1&catalog_name=CTLG&category_name=CTLG_003_010_001_000&product_id=15-1170

It's been a frustrating experience, I hope someone can help.

Since you've been to antennaweb, I'm assuming you're aiming properly.

I'm also assuming you've done a channel scan and it's not some wierd PSIP incompatibility issue with the D* receiver.

The problem when line of sight is lost is usually mulitpath. I would probably try the variable attenuator from RS first as that's cheap and easy. An attenuator can sometimes knock down the reflection enough for the receiver to lock.
Don't use a preamp. That's too close for one and they'll make multipath worse.

If still no success, try repositioning the antenna, changing height (sometimes even lower is better) and non-intuitive aiming. You might be able to tune via a reflected signal. If you have an analog to look at from the same location as the problem digitals it can be helpful to look at it and try to minimize the ghosting. This may also be helpful when trying the attenuator as well.

If you still haven't got it, then you may have to try a different antenna. You need narrow beamwidth and high front-to-back ratio to combat multipath. The CM 4228 would be a good option. Once you're using the 4228, you may need to go back and repeat all of the above steps again.

cpcat

10-12-05, 11:14 PM

Opinions vary on that subject. Please see the 'Two Antenna Trick', it's here. (http://www.hdtvprimer.com/ANTENNAS/silver.html)

That's horizontal stacking. This narrows beamwidth considerably if done properly which helps to combat multipath. I'd say that's a fact and there's little contraversy or varied opinion on it. There does seem to be some disagreement as to whether stacking horizontally increases gain. I believe it does if a low-loss combiner is used.

I'm almost certain Greywolf is familiar with this and was referring to the earlier poster aiming two antennas in different directions which can actually *produce* multipath.

georget

10-13-05, 08:50 AM

He'd prolly say: 'This sure beats grilling with a stick. I can just place the meat on this thing!'
....jc

That's right. He could grill 32 hot dogs at a time on one of these babies, then WHAM! feed 1000 people. My high school cafeteria had similar skills in stretching food.

If it were me, I would call the store that shipped the three antennas and explain what happened. They don't make a lot of money on each one. They could contact UPS to come by and pick them up from your house.

Then go out and buy a Power Ball ticket! $290 mil this week.

TotallyPreWired

10-13-05, 10:13 AM

...There does seem to be some disagreement as to whether stacking horizontally increases gain. I believe it does if a low-loss combiner is used.
I don't know who would disagree that stacking(horizontally or vertically) increases gain. 3db in a perfect situation(which will probably never happen). However, the method in which they are 'combined' makes all the difference.

I'm almost certain Greywolf is familiar with this and was referring to the earlier poster aiming two antennas in different directions which can actually *produce* multipath.
That's pretty much a given. I'm sure that there are people that 'get lucky' but in general it's chances of success are very low.
....jc

cpcat

10-13-05, 10:25 AM

I don't know who would disagree that stacking(horizontally or vertically) increases gain. 3db in a perfect situation(which will probably never happen). However, the method in which they are 'combined' makes all the difference.

Alright, let the fun begin...

I'm on your side, though I'm admittedly biased.

AntAltMike

10-13-05, 11:22 AM

Pointing two directional antennas in different directions and coupling them through a splitter actually works better than you might expect. Digital signals are more immune to degradation by unintended signals and interference than are analog signals. I maintain systems where I have combined signals without filtering out undesired signal and had them work just fine. But of course, I am using a spectrum analyzer and can see whether I am "in the ballpark" with the dB ratio of the desired-to-undersired signals.

Where people always get into trouble is when they point one antenna at the nearby tower(s) and another at the distant ones and amplify the weaker signals, because the amplification of the unintended undesired signal from one antenna will approach or exceed the strength of the intended signal.

AntAltMike

10-13-05, 11:40 AM

In one system, I point one antenna northwest at 34-36, and 39, four miles away, and I point another northeast at 38 and 40, thirty miles away but about 90 degrees off the other antenna's azimuth. I put a channel 42 lowpass filter on the 38/40 antenna downlead and then couple it through a two way splitter with the 34-39 lead, and then pass the combined output through a 32 highpass to accommodate more sophisticated additional combining.

The highly directional antenna pointed to the northeast develops stronger unintended channel 39 than it does of the intended channels 38 and 40, but I can pad down the desired channel 39 so that it is only about 15 to 20dB stronger than the adjacent 38 and 40 and just 10-15dB stronger than the unintended 39, yet the combined signal is readily tunable on all the adjacent channels.

kflorek

10-15-05, 11:06 AM

Hey guys i got the ANT. but something strange has happened.

ant1.jpg
ant2.jpg
ant3.jpg

K Rock XP

From the pics, you have a terrible case of multipath :)

RayL Jr.

10-15-05, 02:28 PM

lol wondering if i should return them.Well, objectively & ethically you should...

I just ordered a push broom w/lifetime warranty via UPS & it was "damaged item/missing in box" from online tracking. I'm pretty sure "Jesus" didn't swipe it, unless maybe it was put to a good cause... ;) Since the shipper I know just wraps & not boxes similar items received, it may be the "new broom" on the UPS warehouse floor...

kflorek

10-15-05, 02:41 PM

Although I have frequently seen it mentioned that the Channel Master 4228 UHF antenna gets adequate reception on the high VHF band, I didn't expect to get anything but snow on VHF from the Winegard PR-9032 UHF-only antenna that I just put up. But hey, all 4 local VHF stations ( 2, 4, 7, and 9) come in snow-free (from about 12 miles away), and channel 11 from Toledo (43 miles away) is snowy but viewable with the rotor pointed in that direction.

My tuner is a plug in PC card, the ATI HDTV Wonder. It also has a second coax input for analog tuning, which seems to be a good tuner too. So I thought I would see if I might get any DX on UHF analog with this 10 foot yagi+corner reflector. Not really; the distant "possibles" are pretty snowy or blanked to a blue-screen. (As antennaweb predicts) The only surprise was Flint from 41 miles away, which has moderate snow. ( I also get a reliable lock from their HDTV broadcast.) Flint happens to lie in the 20 degrees of circumference that is not blocked by a veritable forest of over 50 foot trees on my neighbors' property, so I guess that's why.

Then (why not?) I tried VHF, and got perfect reception. Well almost. No snow. No ghosts (with the rotor adjusted.) It beats anything I ever got from my attic antenna for sure. But the picture looks slightly smeared. Since I also put up a second combo antenna (Channel Master 3679) for a second TV, I know it can look better. VHF analog looks almost digital in comparison on the CM 3679 (a 10 ft all-band)

BTW, I asked if these two antennas might interfere when mounted so close (18 feet mast to mast), and a knowledgable person explained why they likely would not, although for channel 2 it was technically too close. My present estimated distance between the two masts (15 feet) is a little less than I guessed before (18 feet). But the 9032 has no VHF size elements, so... IAC, there is no noticeable problem so far. Thanks to that poster. When the two antennas are pointed at each other, there is only 2 1/2 feet between. I intentionally mounted one antenna 2 feet higher than the other, so they would still miss in case I screwed up somewhere. I have misjudged simpler things...

I admit the over-the-top visual of a 10ft UHF appealed to me. But it should perform pretty close to the much loved CM 4228, with a small wind load in comparison.

Aluminum beats steel. The 4228 is steel, versus the usual aluminum of the 9032. Anything made of steel gets rusty in a few years, and looks bad even if it might actually work OK. Even the zinc-plated, white-painted screws around my aluminum storm doors are rusting and bleeding rust stains on the white aluminum frame. It looks sloppy and neglected.

There was a neighbor that put up a 4228 (or an ancestor) when I was kid. I thought it looked cool, although adults thought "it looked like radar," which was horrid in their eyes. 25 years later, rusted out and looking like an antique, junk bed-spring, it blew down in a storm, such as only hits in twenty years, and the neighbors were all smiles when he said he wouldn't put it back up. It was not in consideration of the neighbors though. He said he hadn't used it in years.

Don't know why, but some pictures have this 9032 with a yellow center bar and blue elements. I was kind of looking forward to it if it came that way. But mine is plain silver aluminum. It has zinc-plated steel rivets and mounts coated with a yellow zinc chromate film. Those will rust in a few years. I put dabs of a one-coat latex metal primer that does not need a top coat on the rivets and hardware in hopes of slowing it down.

Last but not least, the 9032 gives me steady locks on all the HDTV locals, plus Flint. The signal stength on locals in daylight doesn't drop below 80%, whatever per cent means, and will stay around 94%(never 100%) for the best stations at their best position of the rotor . Although I thought that direction was going to be through the 20 degrees of comparatively clear circumference, it turned out to be directly at an immense tree to one side. Oh well. A surprise was Flint WFUM, 41 miles away. The best position is right through the clear 20 degrees. It only gets like 54% strength, and has a narrow range for the rotor direction, but it doesn't drop out. It seems as solid HD as the locals. The big problem with the indoor antenna (for the locals) was drops to 0% every 2 minutes or so. So I'm thrilled with the improvement.

Now that I've got this far, there seems to be another, if small, problem. Several times in an hour, the tuner puts a message in a box at the top, the same message it puts up when it first tunes a digital station: like Video Stream Format 720p. The is no glitch in the sound and the picture may or may not hesitate for a moment, it varies. It seems possible I may be losing a lock for a frame or two. OTOH, it may be software. I know this PC card tuner uses the computer for decoding. It seems to me, the hesitation, if it is, comes where there is a sudden large difference between frames, like when some one is sitting in car and they duck from gunfire, or something like that. That could mean the software did not complete the decoding of the data stream and skipped a frame. But I see no way to rule out a reception problem either. It could mean a higher data rate needs a cleaner signal. Anyone got any ideas or experience on things like this?

RawisJericho

10-15-05, 06:55 PM

My HD TV has a tuner built into it, and I am thinking about getting one of the $12 RCA antennas from Wal-Mart. Are those pretty good, or should I step it up to the $24 model?

DR_LaRRY_PEpPeR

10-17-05, 07:08 AM

Well, almost a week ago I guess (after my last post), I moved the antenna 2-3' more backwards in the attic, trying to aim through a better area. At one point it seemed better, but I don't think it really was. I don't think anything is much different now actually than before I moved it 6 times!

I decided to try the $35 RS 15-1170 pre-amp. Not very good specs, I know (10/6dB gain/noise), but I just wanted to see if the bit of amplification (probably not much with that noise?!) made a difference. Late Friday night after installing it (the old RS amp is still there too), the signals were better than ever -- by about 10%. KETC-9 had 63-69% from 4-6AM, which was a record. But later in the day, they all seemed to drop back to "normal." :( That'll be returned...

Things certainly haven't look any better than before since, unless something else is messed up. BTW, I forgot to mention about the old RS amp -- sometimes it just seems to not amplify the signal properly (every few weeks, and it acted up again after installing the pre-amp). If I go unplug it from power and reconnect it, it'll start working fine again. :confused: Do they kinda get worn out?

I downloaded and tried playing with holl_ands' Fade_Margin spreadsheet (total spreadsheet n00b here! :D), in OpenOffice, no Excel; but I wasn't sure what to put for some of the values (why antenna to pre-amp loss if there's no pre-amp? I thought loss w/o pre-amp would go in the pre-amp to dist-amp/cable loss field), although I seemed to be able to get an idea of the difference in fade margin by changing the pre-amp gain/noise (I also had the other amp's specs in there). I don't understand how VSWR improves with the pre-amp, unless it's because it happens AFTER the pre-amp; or I simply don't understand it. :) Also, I don't think I know what HGTV means. :o

Now I've actually started thinking about what the antenna would be like outside, especially if the attic is causing 15-20dB loss. :) If I would try it, since I don't know what happned to the rest of the antenna hardware for mounting, etc. and so I wouldn't have to put holes in the roof, what do you guys think about laying the antenna across the roof peak?? I've got an idea about how I could guy-wire it (anchored to fascia where the gutter would be -- no gutter on this small second story section) on each side in the middle at the peak and toward the ends, keeping the required angle, etc. Is there a problem with that; would it perform OK (it'd be a couple feet higher than in the attic)? It might not be good for the shingles if it shifts a bit, but I could put a piece of aluminum under the antenna there.

dB-wise, does anyone have a rough idea how much signal strength might change from day to night to allow better reception? Or how little dB difference could there be for a channel to go from no reception or heavy breakups to nearly no breakups (for a couple minutes at least; not necessarily hours)? I'm hoping if I decided to move it outside that I'd get a major improvement! :cool: I'm sure moving it outside would help more than the best pre-amp or a different/additional antenna in the attic, correct?

sregener

10-17-05, 08:17 AM

My HD TV has a tuner built into it, and I am thinking about getting one of the $12 RCA antennas from Wal-Mart. Are those pretty good, or should I step it up to the $24 model?

Try the $12 antenna if you want. If it doesn't work, skip the $24 model and get a Zenith Silver Sensor. For about the same price, it's worlds better.

demisod

10-17-05, 09:30 AM

I recently got a HR10-250 Directv receiver that has built-in ATSC tuners. I was expecting to get pretty good reception from my rooftop antenna since I get good reception from the ATSC tuners in my TV (new Sony A10). However, this has not been the case. The TV's tuner is much better (maybe a more recent chipset?). The TV's signal meter shows stable signals in the 70s and mid-60s for most of the channels. The D* box's meter shows wildly flucuating signals. The peak strength is sometimes OK, but most of the time the signals are in the 20s.

My initial feeling was that the signal was too weak. I based this on a couple of things:

The broadcast towers are about 36 miles away, which I suspect is nearing the limits of the antenna's UHF range, and the antenna does not have a preamp on it. The antenna is a Channel Master U/V/F antenna, about 15 years old -- unfortunately I don't remember the model number or its specs. I believe it is aimed in generally the right direction, but could probably be aimed more accurately.

Analogue signals for the stations are very snowy. I do not see ghosting on the stations, but lots of snow.

However, there is an oddity here. I run the antenna into a three-way splitter, feeding both the TV and the D* box, as well as an A/V receiver for the FM signal. Since I thought signal strength was the issue, I tried running the antenna straight into the D* box. Things got worse. It lost most of the channels it had been detecting and the signal meter dropped considerably on the couple that it could still find. This seems very, very odd to me. Just for grins, I tried hooking a Radion Shack attenuator up before and after the splitter. It didn't make any difference, and truthfully it seems impossible the signal could be too strong at the distances involved. Is there any reason a splitter could improve a weak signal? Is it possible that I have a multipath problem, even though the analogue channels are snowy rather than ghosting?

deconvolver

10-17-05, 10:03 AM

However, there is an oddity here. I run the antenna into a three-way splitter, feeding both the TV and the D* box, as well as an A/V receiver for the FM signal. Since I thought signal strength was the issue, I tried running the antenna straight into the D* box. Things got worse. It lost most of the channels it had been detecting and the signal meter dropped considerably on the couple that it could still find. This seems very, very odd to me. Just for grins, I tried hooking a Radion Shack attenuator up before and after the splitter. It didn't make any difference, and truthfully it seems impossible the signal could be too strong at the distances involved. Is there any reason a splitter could improve a weak signal? Is it possible that I have a multipath problem, even though the analogue channels are snowy rather than ghosting?
If any signal at the tuner input is too strong then it can cause overload that can impact all reception. Where are you located? Do you have any nearby FM radio or TV stations (analog or digital) at all? How do the analog stations look without the splitter? You might just have a bad connection somewhere; how do the connections to the antenna look? In the absence of overloading reducing signal levels does not improve multipath reception so the improvement with the splitter doesn't imply multipath.

demisod

10-17-05, 10:16 AM

deconvolver

10-17-05, 10:31 AM

Ummm. There is a TV station located nearby. The PBS station has a tower about four miles away, although the antenna is not pointed towards it. All the other TV stations are in some antenna farm about 36 miles away. Not sure about FM radio. The PBS station is the only one the D* box consistently picks up. The signal meter reports about 90 on it (but it does flucuate a lot). I realize the meter isn't reporting signal strength but how successfully the signal is being decoded. It's possible the connection on the antenna could be going bad. My roof is very steep and I am reluctant to get up on it any more than is necessary, but that is a possibility.
It is likely that the PBS station is causing overloading. What are your antennaweb.org results including the last columns? If the PBS channel frequency is not close to your other channels then you can get a filter to reduce it. A good directional antenna will also help to reduce the PBS signal. If one side of the antenna connection is bad then there will likely be an increase in the signal from PBS that you are not pointed at and a big decrease in the stations that you are pointed at.

demisod

10-17-05, 11:40 AM

deconvolver

10-17-05, 01:18 PM

The antennaweb.org results are posted at the end. The ones I'm interested in are the UHF stations at 125 degrees. The PBS station is at 228 degrees, but less than two miles away. It's frequency is 59. The others stations are at 55, 53, 52 and 49. Just curious though. If the PBS station is too strong, why do I pick it up? Or is it a case of swamping the other channels? (Assuming that is indeed the problem.)
...

Making sure that your antenna and downlead system is working well is important. Putting up a new UHF only outdoor antenna from Channelmaster or Winegard with RG-6 quad shield downlead would be one way to ensure that.

To reduce the PBS channel level you could get a Channelmaster Join-Tenna that can be ordered from www.warrenelectronics.com to filter channel 59; it should allow you to continue getting PBS but it might reduce your ability to get WB on 57. You could also use a tunable UHF trap like the Winegard UT-2700 but that requires a way to measure channel 59's signal level to tune and would likely kill PBS. By the way, most of your stations will be moving their frequency in the future because they are not in the core band below channel 52. For instance the PBS station has an application to move to channel 25. This means whatever filtering you put in now will not work after the change.

There are a couple of reasons that the strong channel is not the one that you lose from overloading. First of all overloading causes intermodulation products that can swamp weak stations before the strong station is damaged. The second reason has to do with overloading in the receiver because of the way the automatic gain control (AGC) is usually implemented. The AGC circuit usually sets the gain based on a narrowly filtered signal level from just the station being tuned but the front end amplifier carries a much wider band of signals containing many channels. When the strong signal is tuned the TV turns down the front end amplifier so the overloading is reduced or eliminated; but when a weaker channel is tuned the AGC turns up the gain causing the strong channel to saturate the input amplifier. It is possible to make an AGC circuit that measures the same signal that is amplified but for some reason manufacturers don't normally bother to use them.