I dumped DirecTV and am using OTA, Hulu, and Netflix for all my TV viewing. I currently have a 4228 (old model) mounted on a 30 ft tower with a rotator and AP8275 preamp. My location is Zip 34436 which is located about 60 north of Tampa and 45 miles south of Ocala. Without the amp I can get a total of 2 stations which are WTSP in Tampa and WOGX in Ocala both are about 45 miles away but in opposite directions. With the amp I can get a few more stations from Tampa but have trouble with NBC. Most of the Tampa stations are 60 miles at 177deg. I sometimes have better luck locking onto the Orlando NBC (WESH) than I do WLFA in Tampa. At night I can pick up many channels from Orlando which is about 75 miles away.
I use a HDHomeRun connected to a Windows 7 Media Center which requires 2 inputs. Since stations are in 3 different directions tuning becomes a problem when you're using a PVR. I was thinking of either adding another antenna and pointing it in another direction or possibly stacking a second 4228. I was also thinking of replacing the splitter with distribution amp but the signal strength on most of the stations are high (90-100) but the signal quality is running 50-70% which I think means that I'm amplifying noise. I'm open for suggestions on what to try next.

According to that HDTVprimer comparison chart, the Winegard pr-9032 has a gain at channel 14 of 10db... the technical specs at solid signal's website give the gain for that model at channel 14 at 14.9 db.... which one is telling the truth?

The HDTV primer used computer analysis to determine gain. Computer analysis is excellent, but not perfect. HDTV primer has no reason to inflate the numbers.

The Winegard data gives both gain and beamwidth. Gain is related to beamwidth and front to back ratio. Yet, the antenna pattern and gain do not track as you move down to channel 14. Winegard sells more antennas if they inflate their gain numbers.

Based on Winegard's beamwidth and F/B ratio data, I believe that HDTV primer is more likely to be correct.

With the amp I can get a few more stations from Tampa but have trouble with NBC.

That's probably because NBC (WFLA) is using a VHF channel (7) for its digital signal. The 4228 is unusual among UHF antennas for being able to receive high-VHF channels (7-13) fairly well, but it's not comparable to an an antenna that's actually designed for VHF, especially in fringe areas like yours (and mine).

WESH out of Tampa / Daytona Beach is also on VHF (11).

If you're going to add a second antenna, you might consider a high-VHF only antenna like the Winegard YA-1713, specifically to improve those VHF stations.

My location is Zip 34436 ...have trouble with NBC.... possibly stacking a second 4228.

The 4228 has one VHF channel where it is deficient, channel 7. Your NBC is on channel 7.

I'd try a Winegard HD7698P for Tampa and aim the 4228 elsewhere.

The specs that I can find for the CM4228-HD is RF14 - 11.2db, RF19 - 11.6db
The Winegard PR9018, 9022 & 9032 have higher gain from RF 14 to 20 @ 13.3db to 14.9db...HD7084P, HD8200P, HD9095P, PR7052, HD7697P & HD7698P...ALL of these have higher gain from RF 14 to 20...Have you not seen any of these?

Specs/models showing another db here or there are worth about as much as the paper they are printed on.:) I can tell you from experience that both the 8200P and the 9032 are poorer performers than the 4228 for low uhf.

To get noticeably better performance for lo UHF than the 4228 you'll need to either go with a dedicated low uhf antenna (for example the Triax 100A) or stack antennas for additional gain.

Specs/models showing another db here or there are worth about as much as the paper they are printed on.:) I can tell you from experience that both the 8200P and the 9032 are poorer performers than the 4228 for low uhf.

To get noticeably better performance for lo UHF than the 4228 you'll need to either go with a dedicated low uhf antenna (for example the Triax 100A) or stack antennas for additional gain.

Have you had any contact lately with cpc? Looks like they are getting out of the antenna hardware business.

To get noticeably better performance for lo UHF than the 4228 you'll need to either go with a dedicated low uhf antenna (for example the Triax 100A) or stack antennas for additional gain.

Or both.;)

Have you had any contact lately with cpc? Looks like they are getting out of the antenna hardware business.

It's been a little over a year since I've bought anything from them. I noticed the same thing as you when searching their website recently.

It may soon be necessary to look for another source for Euro antennas. Bummer if that is the case.:(

rabbit73,

Id be interested in seeing a comparison analysis of your new digital meter compared to the two signal meters on your Apex DT502 CECB.
Here is the comparison for my Apex DT502. Most of the signal level readings were made with the DisplayMax 800, but I added a few from the 719E for comparison or when the level was too low for the 800. The specs for the 800 say that it can read digital down to -23dBmV. When the level is too low for it, the display says "Ur." which means Under Range. I used the same box #1 as last time, first in a strong signal location:

Attenuator Quality Strength DM800 719E
dB % % dBmV dBmV

0 100 84 +14.1 +12.5
3 100 84 +11.2
6 100 84 +7.6
9 100 83 +4.8
12 100 80 +2.5
15 100 75 -0.8
18 100 72 -4.6
21 100 67 -7.7
24 100 64 -10.2
27 100 60 -12.8
30 100 56 -14.9
33 100 53 -17.1
36 100 47 Ur. -23.0
39 100 42 -27.2
42 100 37 -28.5
45 66 27 -35
48 34 0

The OTA readings seemed to vary a bit that day, probably because of the strong wind through the trees that are in the signal path.

and then in a weak signal location:
Attenuator Quality Strength DM800 719E
dB % % dBmV dBmV

0 100 62 -14.1 -17.5
3 100 54 -16.3
6 100 49 -18.4
9 100 44 Ur. -26.0
12 99 37 -29.5
15 81 32 -35
18 21 0 -38
21 Dropout

I think that all CECBs should have two signal bars because of the importance of signal QUALITY for digital reception. So far, I have tested the Zinwell ZAT-970A, the Apex DT502, and the Sansonic FT300A. My first choice as a measurement tool is the Apex. The Zinwell and Sansonic don't always give consistent readings for the same input, and the Sansonic bars take a long time to respond to changes.

Where is a good source for European Antennas? Ive been looking, but cant find anything.

Specs/models showing another db here or there are worth about as much as the paper they are printed on.:) I can tell you from experience that both the 8200P and the 9032 are poorer performers than the 4228 for low uhf.

To get noticeably better performance for lo UHF than the 4228 you'll need to either go with a dedicated low uhf antenna (for example the Triax 100A) or stack antennas for additional gain.


Though it's not another db here and there.. the difference between specs from one to the other was 5 db! So, I guess your'e basically saying Winegard is lying about that model by 5 db? So I guess according to the HDTV primer data, that the pr-8800 is the one to get... unless you think the redesigned 4228 will outdo it? I couldn't understand that gain chart you posted for the triax 100a..... there's 3 curves on it? And it only shows data down to channel 21, I'm looking for data from channels 14-20.

Though it's not another db here and there.. the difference between specs from one to the other was 5 db! So, I guess your'e basically saying Winegard is lying about that model by 5 db? So I guess according to the HDTV primer data, that the pr-8800 is the one to get... unless you think the redesigned 4228 will outdo it? I couldn't understand that gain chart you posted for the triax 100a..... there's 3 curves on it? And it only shows data down to channel 21, I'm looking for data from channels 14-20.

The 4228 or XG91 are probably your best bets for a domestically available long range wide band uhf antenna.

The UK channel 21 is equivalent to US channel 14. In the UK "Band A" is 21-37 while in the US the equivalent is 14-36. The 100A is good up to about US channel 38 and then it starts dropping like a rock. I've never seen a gain chart/graph for the Triax Unix 100A. Triax simply quotes the gain as 17db.

The Funke site has a chart for their band A model which should be roughly equivalent:

http://www.funke.nl/library/225_142002_dc4591_081203_790501450.pdf?PHPSESSID=63644a4048b 3366f008fd92772d6fb15

UK channel frequencies and grouping:

http://www.tvaerials.com/uk_frequencies.aspx

I don't need a wide band antenna, I've got an XG-91 (2 piggybacked on each other, actually) pointed in the directions of the bulk of my stations, and I want another to point at my secondary stations, which are 15 and 17. I'm tired of the rotor and it's "creep" and the high wind blowing my antenna out of adjestment, so I'm going with 2 "fixed" units, and doing the A/B switch thing (This is the way I had my setup years ago, and it was alot less trouble) If you seem the think antenna manufacturers lie about the gain to increase sales, I wouldn't be any more likely to believe Triax's gain claims than Winegard's. It seems like everything I read never has any real world relevance. I tried vertical stacking and horizontal stacking on those XG-91's and saw NO increase in signal strength... it wans't unitl I screwed aruond and simply "balanced" one antenna directly on top of the other one... the bottom one sticking out forward about 10 inches farther than the top one, THEN I got a 10 percent increase in signal strength across the board. So I wrapped them up with duct tape to fasten them together, and tied the reflectors together with zip ties, and there you go. But since that XG-91 peaks it's gain in the obselete 52-69 channels, I'm going for something that will peform on 15 and 17, which most seem not to do. That HDTVprimer graph shows most drop like a rock under channel 20.

I don't need a wide band antenna, I've got an XG-91 (2 piggybacked on each other, actually) pointed in the directions of the bulk of my stations, and I want another to point at my secondary stations, which are 15 and 17. I'm tired of the rotor and it's "creep" and the high wind blowing my antenna out of adjestment, so I'm going with 2 "fixed" units, and doing the A/B switch thing (This is the way I had my setup years ago, and it was alot less trouble) If you seem the think antenna manufacturers lie about the gain to increase sales, I wouldn't be any more likely to believe Triax's gain claims than Winegard's. It seems like everything I read never has any real world relevance. I tried vertical stacking and horizontal stacking on those XG-91's and saw NO increase in signal strength... it wans't unitl I screwed aruond and simply "balanced" one antenna directly on top of the other one... the bottom one sticking out forward about 10 inches farther than the top one, THEN I got a 10 percent increase in signal strength across the board. So I wrapped them up with duct tape to fasten them together, and tied the reflectors together with zip ties, and there you go. But since that XG-91 peaks it's gain in the obselete 52-69 channels, I'm going for something that will peform on 15 and 17, which most seem not to do. That HDTVprimer graph shows most drop like a rock under channel 20.

Pointing antennas in different directions will likely require you to add filtering such as a jointenna. You'd need to check around for availability on filters specific for the channels you need.

Probably the better option is to maximize a single antenna(s) and use a rotator. I have to recalibrate my rotator all of the time. It's just part of being in the fringe. Horizontally stacked XG91's should provide better performance than a single Unix 100A for low uhf.

Sounds like you are having problems getting the two xg91s to phase properly. You might double-check the baluns on them. Older xg91s used a ferrite balun and you may need to swap the polarity to match them. If this is the case, you simply swap one of the 300ohm balun leads on one of the antennas to match them. Out of phase antennas have a forward null while in-phase antennas have a forward lobe so it's not hard to tell. I won't insult you by telling you to be sure the leads from the antenna to the combiner are exactly the same length.

You could also go with an XG91 for upper uhf and a 100A for lower uhf. Again, you'd need a filter designed for this for best performance. Triax makes one if you can find a source.

Though it's not another db here and there.. the difference between specs from one to the other was 5 db! So, I guess your'e basically saying Winegard is lying about that model by 5 db? So I guess according to the HDTV primer data, that the pr-8800 is the one to get... unless you think the redesigned 4228 will outdo it? I couldn't understand that gain chart you posted for the triax 100a..... there's 3 curves on it? And it only shows data down to channel 21, I'm looking for data from channels 14-20.

Good response...but keep in mind that on this forum most people (not me though) are in love with anything from Channel Master and won't even consider anything else.

Tired of rusty steel mast, does 1" aluminum schedule 40 pipe seem like it would be as strong as 16 Ga steel pipe, standard 1 1//4" mast? It would be under 10' in length. If not, any suggestions?

The 4228 has one VHF channel where it is deficient, channel 7. Your NBC is on channel 7.

I'd try a Winegard HD7698P for Tampa and aim the 4228 elsewhere.

Thanks,
That's a big puppy....and expensive. I would most likely have to remove it if we get another hurricane here. The 4228 came through fine on the last one we had with 80mph winds but I don't know what would happen with that plus the 7698p on the same mast.

Tired of rusty steel mast, does 1" aluminum schedule 40 pipe seem like it would be as strong as 16 Ga steel pipe, standard 1 1//4" mast? It would be under 10' in length. If not, any suggestions?

It depends on the alloys of the steel and aluminum.

Good aluminum is stronger than galvanized water pipe but TV mast is often much stronger than water pipe. The strongest aluminum is usually sized as tubing and not pipe, but there are exceptions.

Thanks,
That's a big puppy....and expensive. I would most likely have to remove it if we get another hurricane here. The 4228 came through fine on the last one we had with 80mph winds but I don't know what would happen with that plus the 7698p on the same mast.


You could add an Antennacraft Y10 7-13 without too much added wind load, especially if you mount it fixed below the rotator. It's cheap too. Combine it with the 4228 using a u/v combiner before the preamp.

I've never seen a gain chart/graph for the Triax Unix 100A.

I've posted it here before,I think.Here it is.



http://alpha.future.ee/triax_unix.png

Pointing antennas in different directions will likely require you to add filtering such as a jointenna. You'd need to check around for availability on filters specific for the channels you need.

What would I need a filter for? Yes, I point 2 antennas in two different directions, and I have seperate coax for each one. The the A/B switch selects which antenna's signal is fed into the TV at any given time.

Tired of rusty steel mast, does 1" aluminum schedule 40 pipe seem like it would be as strong as 16 Ga steel pipe, standard 1 1//4" mast? It would be under 10' in length. If not, any suggestions?

As a general rule of thumb steel pipe is 3 times stronger than aluminum of the same dimension.Not much difference in cost to move up to 1-1/4 Sch40 which would be a lot stronger than 1 inch.I use a lot of 1-1/4 and sleeve it with 1" aluminum or steel at high stress points.Here's a pic of the UHF tower.All 1-1/4" aluminum masting down to the rotor.

What would I need a filter for? Yes, I point 2 antennas in two different directions, and I have seperate coax for each one. The the A/B switch selects which antenna's signal is fed into the TV at any given time.

With the A/B switch you don't need filters.
If you wanted to run both antennas down the same lead you would.

I never knew people tried to put two opposite antennas down the same coax, I would never even dream of trying such a thing. I do wonder something.... how is digital when it comes to adjacent channel intereference? My weak station Digital 17, but I have a stronger digital 18 (Noise margin +36.1), which I do lock onto at times (drops out) from the backside of my antenna when it's pointed at 17.... however, that digital 18 is not LOS, nor is any other channel I can receive. Think it might cause a problem? And if so, are there ways to correct such things?

What would I need a filter for? Yes, I point 2 antennas in two different directions, and I have seperate coax for each one. The the A/B switch selects which antenna's signal is fed into the TV at any given time.

Correct you don't need a filter if you use an a/b switch. Sorry I missed that.

Good luck.:)

I've posted it here before,I think.Here it is.



http://alpha.future.ee/triax_unix.png
Cool, I've never seen that.
Makes me want to try 4 K-banders. ;)

Here is the comparison. Most of the signal level readings were made with the DisplayMax 800, but I added a few from the 719E for comparison or when the level was too low for the 800. The specs for the 800 say that it can read digital down to -23dBmV. When the level is too low for it, the display says "Ur." which I assume to mean unreadable. I used the same box #1 as last time, first in a strong signal location:

Attenuator Quality Strength DM800 719E
dB % % dBmV dBmV

0 100 84 +14.1 +12.5
3 100 84 +11.2
6 100 84 +7.6
9 100 83 +4.8
12 100 80 +2.5
15 100 75 -0.8
18 100 72 -4.6
21 100 67 -7.7
24 100 64 -10.2
27 100 60 -12.8
30 100 56 -14.9
33 100 53 -17.1
36 100 47 Ur. -23.0
39 100 42 -27.2
42 100 37 -28.5
45 66 27 -35
48 34 0

The OTA readings seemed to vary a bit that day, probably because of the strong wind through the trees that are in the signal path.

and then in a weak signal location:
Attenuator Quality Strength DM800 719E
dB % % dBmV dBmV

0 100 62 -14.1 -17.5
3 100 54 -16.3
6 100 49 -18.4
9 100 44 Ur. -26.0
12 99 37 -29.5
15 81 32 -35
18 21 0 -38
21 Dropout

I think that all CECBs should have two signal bars because of the importance of signal QUALITY for digital reception. So far, I have tested the Zinwell ZAT-970A, the Apex DT502, and the Sansonic FT300A. My first choice as a measurement tool is the Apex. The Zinwell and Sansonic don't always give consistent readings for the same input, and the Sansonic bars take a long time to respond to changes.

Thanks for posting the data, it will come in handy.

Yeah, my Sansonic FT300A bars take time to respond to changes too. I imagine youll post a similiar comparison to it later too.

As a general rule of thumb steel pipe is 3 times stronger than aluminum of the same dimension.

It really depends on the alloy.

Black iron (water pipe) yield strength ~ 30,000 PSI
Low carbon steel yield strength ~ 36,000 PSI
Aircraft grade 4130 steel yield strength ~ 50,000 PSI
High carbon steel yield strength ~ 87,000 PSI
Tool steel yield strength as much as 100,000 PSI

Aluminum alloys
6063 (no temper)15,000 PSI
6063 T832 40,000 PSI
3003 21,000 PSI
2024 42,000 PSI
6061T6 35,000 PSI

Typical comparison info for ham masts:
http://www.texastowers.com/steelmasts.htm

If you select steel masts for strength purposes, make sure that it is high carbon steel. Water pipe doesn't cut it.

I think I'm in the wrong post, but I did a forum search for FM antenna and this popped up. I live in an apartment building and my FM reception is pretty bad. I'm not looking to spend much ($20-$30) as I hope to get a new HT receiver (currently Onkyo 601) in a couple years that will probably have HD Radio (if it's still around) as well as support for my digital collection. But what is the best low-cost antenna out there? I'm guessing amplified is the way to go.

thx

Cool, I've never seen that.
Makes me want to try 4 K-banders. ;)

Well,good luck finding those.I noticed cpc had some listed a few months ago-but have disappeared.Bet a dollar to a doughnut they don't have any Band A's either.cpc was the only company in the UK that was reasonable and easy to do business.I think our Euro pipeline for the good stuff has dried up:(

It really depends on the alloy.

Black iron (water pipe) yield strength ~ 30,000 PSI
Low carbon steel yield strength ~ 36,000 PSI
Aircraft grade 4130 steel yield strength ~ 50,000 PSI
High carbon steel yield strength ~ 87,000 PSI
Tool steel yield strength as much as 100,000 PSI

Aluminum alloys
6063 (no temper)15,000 PSI
6063 T832 40,000 PSI
3003 21,000 PSI
2024 42,000 PSI
6061T6 35,000 PSI

Typical comparison info for ham masts:
http://www.texastowers.com/steelmasts.htm

If you select steel masts for strength purposes, make sure that it is high carbon steel. Water pipe doesn't cut it.

I've used Sch40 pipe, steel and aluminum,which have similar specs,but in actual use the steel is much stiffer.I use Aluminum because of the weight savings realized when lifting the tower from the ground to vertical,as well as the rusting issue.But,after watching the array last night taking a hammering with 50mph wind gusts,I think I'll replace the 1-1/4" AL(1-5/8" OD) with steel from the rotor up thru the top bearing.It bends in the middle too much(7ft unsupported).

I think I'm in the wrong post, but I did a forum search for FM antenna and this popped up. I live in an apartment building and my FM reception is pretty bad. I'm not looking to spend much ($20-$30) as I hope to get a new HT receiver (currently Onkyo 601) in a couple years that will probably have HD Radio (if it's still around) as well as support for my digital collection. But what is the best low-cost antenna out there? I'm guessing amplified is the way to go.

thx
You can calculate signal strengths using www.tvfool.com
If your signals are strong enough, a folded dipole should
work quite well. Connect to receiver via a 300-to-75-ohm
(Balun) Transformer:
http://www.wfu.edu/~matthews/misc/dipole.html
If you have an attic, adding a reflector and optional director increases gain.

Or use simple Rabbit Ears, since FM Band is just above Ch6:
http://www.ham-radio.com/k6sti/rabbit.htm

You can use an amplified antenna if FM signal strengths (and Ch6)
are LESS than about -25 dBm ("LESS" would be -26 dBm).

FYI: Some (too much???) high performance FM Antenna Info:
http://www.ham-radio.com/k6sti/
http://www.aphenos.net/misc/electronics/suppliers/FM_DXing_Antennas.htm

A couple of questions regarding mounting antennas. If I decide to mount separate UHF and VHF high antennas on the same mast, how far must one be above the other? If I use guide wires to add stability, how far below the lowest of the two antennas do the wires need to be fastened to the mast?
Thanks

Old rule of thumb used to be something like one wavelength of the lowest frequency, but of course thats not practical in most cases. Try to get as much distance between them as you can without sacrificing structural stability.

A couple of questions regarding mounting antennas. If I decide to mount separate UHF and VHF high antennas on the same mast, how far must one be above the other? If I use guide wires to add stability, how far below the lowest of the two antennas do the wires need to be fastened to the mast?
Thanks

Rule of thumb is 36 inches for uhf, 48 for hi vhf, and 60 for lo vhf. 36 would probably still be ok for hi vhf especially if you only need the higher vhf channels say 10 and above. Spacing to prevent interference is measured from nearest metallic elements.

I think I'm in the wrong post, but I did a forum search for FM antenna and this popped up. I live in an apartment building and my FM reception is pretty bad. I'm not looking to spend much ($20-$30)
thx... use simple Rabbit Ears, since FM Band is just above Ch6If you're not a long way from the radio transmitter towers, a simple rabbit ear antenna works well. This one from Radio Shack works particularly well with FM and HD radio:
http://www.radioshack.com/product/index.jsp?productId=2103077
I'm using one for FM/HD radio stations ~45 miles away.

Leave off the loop part of the antenna when assembling it. It is for UHF TV band. You only need to attach the two dipole elements for FM reception.

MaxHD,

My new Rohn Tower was checked out this week. We had 70 MPH winds last night, and no issues with the horizontal stack of 91XG's and the High Bander on the bottom. The neighbors did not make it. They had the American Tower brand and it bend over.

I am considered to be the king on the road, as all of my neighbors that I would have bought the farm. I had two full truck loads of concrete for the base. I can post pictures if needed.

It depends on the alloys of the steel and aluminum.

Good aluminum is stronger than galvanized water pipe but TV mast is often much stronger than water pipe. The strongest aluminum is usually sized as tubing and not pipe, but there are exceptions.
Where does one find a "Good" "TV mast?" I was looking to use 10' of 1" and a sleeve from 1¼" galvanized water pipe for top dry bearing and mast shaft. This will support the mounting of a Channel Master 3020 on a 40' tower (which I would like to add another 10'), anchored to the eave of my single story residence.

MaxHD,

My new Rohn Tower was checked out this week. We had 70 MPH winds last night, and no issues with the horizontal stack of 91XG's and the High Bander on the bottom. The neighbors did not make it. They had the American Tower brand and it bend over.

I am considered to be the king on the road, as all of my neighbors that I would have bought the farm. I had two full truck loads of concrete for the base. I can post pictures if needed.

Like I told you,you're out of spec for 25,but it's very tuff tower for sure.No pics needed,but a video of the stuff wavin in the wind would be cool :)

Where does one find a "Good" "TV mast?" I was looking to use 10' of 1" and a sleeve from 1¼" galvanized water pipe for top dry bearing and mast shaft. This will support the mounting of a Channel Master 3020 on a 40' tower (which I would like to add another 10'), anchored to the eave of my single story residence.

Just use 1" galvanized pipe(1-1/4" OD)

So, I can go ahead with my initial idea of 1" and using the 1¼" Galv Pipe as the outside sleeve (fits inside the through hole on the top of my tower) for a top bearing? Good to know. After the analog shutdown happens and the stations get settled, I'll need to re-evaluate my main antenna.

Here is the comparison for my Apex DT502. Most of the signal level readings were made with the DisplayMax 800, but I added a few from the 719E for comparison or when the level was too low for the 800. The specs for the 800 say that it can read digital down to -23dBmV. When the level is too low for it, the display says "Ur." which I assume to mean unreadable. I used the same box #1 as last time, first in a strong signal location:

Attenuator Quality Strength DM800 719E
dB % % dBmV dBmV

0 100 84 +14.1 +12.5
3 100 84 +11.2
6 100 84 +7.6
9 100 83 +4.8
12 100 80 +2.5
15 100 75 -0.8
18 100 72 -4.6
21 100 67 -7.7
24 100 64 -10.2
27 100 60 -12.8
30 100 56 -14.9
33 100 53 -17.1
36 100 47 Ur. -23.0
39 100 42 -27.2
42 100 37 -28.5
45 66 27 -35
48 34 0
The OTA readings seemed to vary a bit that day, probably because of the strong wind through the trees that are in the signal path.

and then in a weak signal location:
Attenuator Quality Strength DM800 719E
dB % % dBmV dBmV

0 100 62 -14.1 -17.5
3 100 54 -16.3
6 100 49 -18.4
9 100 44 Ur. -26.0
12 99 37 -29.5
15 81 32 -35
18 21 0 -38
21 Dropout
I think that all CECBs should have two signal bars because of the importance of signal QUALITY for digital reception. So far, I have tested the Zinwell ZAT-970A, the Apex DT502, and the Sansonic FT300A. My first choice as a measurement tool is the Apex. The Zinwell and Sansonic don't always give consistent readings for the same input, and the Sansonic bars take a long time to respond to changes.
rabbit73,

Here are APEX DT502 readings of stations I'm receiving:

Station|Strength|Quality|Notes
WMAR-DT|61%|30%|Heavy ±, 2-edge
WBAL-DT|58%|29%|Heavy ±, 2-edge
WJZ-DT|84%|100%|Solid, 2-edge
WUTB-DT|70%|80%|Minor ±, 2-edge
WWPB-DT|84%|23%|Off-Axis, 21 mile LOS (local)
WNUV-DT|78%|100%|Solid, 2-edge
WWPX-DT|85%|54%|Off-Axis, 34 mile LOS (local)

NOTE: My setup is a decoupled CM3020, with a 0265DSB pre-amp, mounted on top of a 40' tower. This is then fed into a Trunkline 20-TDA25 25dB DA via a 6dB In-Line attenuator. From the DA, I have a 2-way splitter that feeds house distribution of about 40-50' to another 2-way.

rabbit73,

Here are APEX DT502 readings of stations I'm receiving:

Station Strength Quality Notes
WMAR-DT 61% 30% Heavy ±, 2-edge
WBAL-DT 58% 29% Heavy ±, 2-edge
WJZ-DT 84% 100% Solid, 2-edge
WUTB-DT 70% 80% Minor ±, 2-edge
WWPB-DT 84% 23% Off-Axis, 21 mile LOS (local)
WNUV-DT 78% 100% Solid, 2-edge
WWPX-DT 85% 54% Off-Axis, 34 mile LOS (local)

NOTE: My setup is a decoupled CM3020, with a 0265DSB pre-amp, mounted on top of a 40' tower. This is then fed into a Trunkline 20-TDA25 25dB DA via a 6dB In-Line attenuator. From the DA, I have a 2-way splitter that feeds house distribution of about 40-50' to another 2-way.

Interesting, I can almost see the noise caused by the DAs in your system. Im at 61 miles from my transmitters, using a DBGH uhf with a CM1221 modded for future vhf (no vhf DT stations yet) 25 ft on the roof, with a CM0264 into a two way splitter and an AB switch for a second DBGH. Most of my Apex DT502 quality readings for the signal strengths you have listed or above are at 100%, like rabbit73s chart.

If I remove the DA, I would probably only get WJZ-DT and WNUV-DT.

So, I can go ahead with my initial idea of 1" and using the 1¼" Galv Pipe as the outside sleeve (fits inside the through hole on the top of my tower) for a top bearing? Good to know. After the analog shutdown happens and the stations get settled, I'll need to re-evaluate my main antenna.

I don't have enough info on what you have or what you're doing,but the pipes will turn inside each other.With a hole in the tower top,I'd use a 1-1/4" floor flange bolted on top with nothing else or maybe a very short stub of pipe screwed into the flange.Again,I don't know your complete configuration plan.

My station strengths:

STATION|ANALOG|CURRENT|FUTURE|NM (dB)
WMAR-DT|2|52|38|-21.5
WBAL-DT|11|59|11|-23.1
WJZ-DT|13|38|13|-17.2
WUTB-DT|24|41|41|-24.9
WHAG-DT|25|55|26|+59.2
WWPB-DT|31|44|44|+47.7
WNUV-DT|54|40|40|-19.0
WWPX-DT|60|12|12|+42.6
WJAL-DT|68|-|39|+53.7NOTE: WHAG-DT and WJAL-DT will not be receivable until after analog shutdown.

Short piece of 1¼" galv with couplers top and bottom (cheaper than floor flnges). :)

If I remove the DA, I would probably only get WJZ-DT and WNUV-DT.

Oh yeah, I didnt mean to imply to remove them. You need them to drive the additional cable runs you must have. I was just noting the quality per the DT502 and my system and your system.

but the pipes will turn inside each other
Or a small hole with a bolt thru both pipes.

I'm using an indoor antenna and I've currently had the best results with an old RS 15-1864 RE and loop, although I've tried a RCA ANT121 and a RS delta and an RS 22 db amplified antenna.
I pick up all the UHF channels with pretty stable strengths running between 65 and 98 depending on the channel but was having trouble with two high VHF channels. I'm about 25 miles from all the signals. Placing the antenna in the window is about the same as inside the room near the ceiling, but touching the rabbit ears to the window edges (metal) improves the signal enough to pick up the VHF channels. Could someone explain this to me?

Thanks.

Placing the antenna in the window is about the same as inside the room near the ceiling, but touching the rabbit ears to the window edges (metal) improves the signal enough to pick up the VHF channels. Could someone explain this to me?VHF doesn't travel through walls as well as UHF does. Also, certain kinds of wall insulation and types of window glass can block TV signals. The metal window frame may be picking up enough signal from outside to allow reception when the dipoles touch it.

On one TV, I've had very good results using this rabbit ear/loop antenna (http://www.radioshack.com/product/index.jsp?productId=2103077), which has a larger gauge coax than most cheap set top antennas. Placed against an outside wall, I'm getting channels from over 45 miles away. YMMV, of course.

Or a small hole with a bolt thru both pipes.
But I want the 1" pipe to turn, because it will be bottomed by my Channel Master rotator.

I've devised a mount for my rotator, by drilling holes through one of the three legs of the tower. I mount two American Valve, #302038, 1" galvanized "Split Ring Hanger" pipe clamps, with 3/8"x4" galvanized bolts and 2" spacers (by using ½" EMT as spacers, this gives me room to clear the supports and, to mount and center the rotator on the tower). I place a 3/8" galvanized washer between the spacer and the "Split Ring Hanger" to give the hanger something to rest against. By clamping the "Split Ring Hanger" around a 1" galv pipe of five or ten feet, I have the ability to move the rotator up and down the pipe to peak the antenna, which is mounted to a 10'x1" galvanized pipe.

But I want the 1" pipe to turn, because it will be bottomed by my Channel Master rotator.

Ahh sorry, misunderstood. "Never mind" - Gilda Radner SNL. But stop busting them school children, heh.

Hey Rick0725,

Nice to hear you chime in.

Do you have a preference between the Winegard YA-1713 vs. the Antennacraft Y10-7-13? The Winegard is supposedly a bit weak on channel 13, but I don't know if switching to the Antennacraft would be worth the trouble????

Thanks again for all your help!! Glen

I'm using a CM0265DSB, so that I can have seperate UHF/VHF inputs and not have the balun loss. I was thinking about modifying the UHF segment like the HDTVExpert website did to a CM3022. http://hdtvexpert.com/pages/cm3022.htm

You still have Balun Loss....they're INSIDE the Preamp.

Is there a reason why TV antennas aren't manufactured with 75 ohm impedence instead of 300 ohm? The only 75 ohm TV antennas I have ever seen were cut for a single channel.

How does the winegard hda 100 compare to the CM3412?

I understand there would be a balun inside the pre-amp, although I would think it would be designed and tuned for the pre-amp circuit and give better performance.

Is there a reason why TV antennas aren't manufactured with 75 ohm impedence instead of 300 ohm? The only 75 ohm TV antennas I have ever seen were cut for a single channel.

I thought that the Winegard HD76XXP series were 75 ohm?

I thought that the Winegard HD76XXP series were 75 ohm?No,

They are 300 ohm with a snap on, weatherproof balun.

What is the word on the street regarding the AD Clearstream 2? I am looking for a portable antenna, e.g. one that won't damage my car easily. The CM4220 I have available is very rough around the edges. I have a Silver Sensor for the purpose right now, but am looking for something a little more robust.

The CS2 seems to be smaller than I had thought and has a reflector, something my home-builds lack. The CS1 is small enough to point out the window, but doesn't seem to have much of an advantage over the Silver Sensor.

I would also be curious if anyone has tested the upper VHF performance of the CS series. Despite the marketing hype, I would be surprised if they are above -8dB.

Thank you for any info.

...I would also be curious if anyone has tested the upper VHF performance of the CS series...I don't have the source handy, but I read the VHF performance was poor (seems like it was a review at hdtvexpert, but not sure).

I also will not purchase from companies that overly hype their products and repeatedly publish misleading gain information.

My neighbor and I tested the CS1, 2, & 4 against the Winegard 1080. None of the CS antennas would decode a LP digital channel 8 only 6 miles away.(That channel 8 is wedged between full power analog channels 7 & 9@4 miles away) The 1080 was the only antenna able to decode the channel.(Signal meter steady around 60% on the Zenith DTT-901) The UHF performance is somewhat better on the CS 2 & 4. The CS antennas don't seem to have any more gain on VHF-HI than my 91-XG.

I found out this morning that my tower (I aquired it from a dismantle) appears to be made by American Tower (http://www.amertower.com/) (Amerite) and is the 5 step - two hole - GCS Series Communication Tower, with a GT-3 top.

I don't have the source handy, but I read the VHF performance was poor (seems like it was a review at hdtvexpert, but not sure).


Thanks. I found the article:

http://www.hdtvexpert.com/pages_c/Five_Antennas.html

AD's marketing hype reminds me of Monster, but if a CM2016 has the aluminum rust that I'm accustomed to from CM, I don't think I want that in my car. I've already tried an HD-1080, but its performance left much to be desired. It's hard to get something small and easy to work with for any kind of VHF gain, so I think I will forget about VHF for mobile tests, outside of the rabbit ear/loop combo I have.

I did some research and found information on an antenna that was snagged with the tower. It appears to be a Channel Master Quantum. I'm not sure which model (it's not the 1111), but I think it must be a 1162, 1161, or a 1160A. It has nine front directors, two sets (top/bottom) of L1-L5 UHF elements, and two sets (top/bottom) of five VHF elements (the last two sets (longest) are broken off), three sets of floating directors, and four (maybe five), top-side, center directors. Seems like it's the major antenna around here. I see it everywhere.

Would this be better than my CM3020?

Probably not. The Quantum antennas were excellent for VHF, but weak on UHF. A good separate UHF antenna would easily ouperform either antenna. There is no "combo" antenna out there that will work better on UHF than a good UHF only antenna. Only the Winegard 8200 comes close.

The CS2 seems to be smaller than I had thought and has a reflector, something my home-builds lack. The CS1 is small enough to point out the window, but doesn't seem to have much of an advantage over the Silver Sensor.

The C2 would be good for car, boat or RV use. But just dont expect great gain from it. Also at $99 at my local Best Buy, it is far from a bargain.

Thanks for the explanation, arxaw.

I did some research and found information on an antenna that was snagged with the tower. It appears to be a Channel Master Quantum. I'm not sure which model (it's not the 1111), but I think it must be a 1162, 1161, or a 1160A. It has nine front directors, two sets (top/bottom) of L1-L5 UHF elements, and two sets (top/bottom) of five VHF elements (the last two sets (longest) are broken off), three sets of floating directors, and four (maybe five), top-side, center directors. Seems like it's the major antenna around here. I see it everywhere.

Would this be better than my CM3020?

Both DTT-901's I have installed for friends have been on Quantums 1 on a 1160 and 1 on a 1162, on the 1160 I was able to get all DC and Baltimore stations with the antenna in one position (rotators broken). On the 1162 I was able to get all DC execpt WTTG all Baltimore, Lancanster, York and WLYH. Hagerstown, Martinsburg (even W08EE at 300 watts) and WYVP out of Front Royal (with a Rotator) You see many Quantums in this area (for there UHF ability)

I've seen many of these single channel yagis and UHF yagis from them with narrow frequency range. Quite pricey... but they say theyr'e 75 OHM impedance, I guess they don't need a balun? The UHF for channels 14-19 says it's gain is 12.2, with a front to back ratio of 21. These are pricey, what is the advantage to these? Or are they just overpriced? Other much cheaper antenna advertize the same amount of gain.

AD's marketing hype reminds me of MonsterIf A. D. spent more time making decent antennas than they do trying to mislead the public with marketing hype and downright lies, they would probably come up with something I would consider buying.

I've seen many of these single channel yagis and UHF yagis from them with narrow frequency range. Quite pricey... but they say theyr'e 75 OHM impedance, I guess they don't need a balun? The UHF for channels 14-19 says it's gain is 12.2, with a front to back ratio of 21. These are pricey, what is the advantage to these? Or are they just overpriced? Other much cheaper antenna advertize the same amount of gain.
B-T antennas are reportedly of heavier duty construction to survive high winds,
long term reliability for commercial users.....and perhaps crows sitting on them.....

All 75-ohm antennas (like W-G YA-1713 et. al.) use a 1:1 Balun so that
the antenna pattern is not disturbed by an unbalanced feed and to minimize
local "common mode" noise pickup....the reverse of the argument for
using 1:1 Baluns in transmit antennas--prevent radiation leakage from coax.

FYI: Someone in our local forum found A-D ClearStream C1, C2 & C4 Spec Sheets:
http://www.antennasdirect.com/pdf/C1-sellsheet.pdf
http://www.antennasdirect.com/pdf/C2-sellsheet.pdf
http://www.antennasdirect.com/pdf/C4-sellsheet.pdf

Note C4 gain is about 12 dBi, which is a lot lower than "14.8 dBi" found on website:
http://www.antennasdirect.com/C4-Clearstream-DTV-antenna.html
http://www.antennasdirect.com/pdf/ClearStream.pdf
but is much more consistent with C2 specs.

BTW: In C2 & C4 Gain/VSWR Charts, Y-axis is trying to do double duty.
But VSWR should be labeled as a scalar number---NOT dB like Gain:
http://www.antennasdirect.com/ClearStream2Gain.html

BTW: In C2 & C4 Gain/VSWR Charts, Y-axis is trying to do double duty.
But VSWR should be labeled as a scalar number---NOT dB like Gain:

Ahh, I missed that point on my first read thru some time ago. My pet peeve is labeling the graph "Directivity" instead of Directive Gain. Directivity only implies angular position to me. Who does their graphs, heh ?

I also note that the reflectors shown in the above ClearStream.pdf literature are not what I measured at my local Best Buy's ClearStream2. I measured 1 1/2" X 2" mesh running the other way and the edges were bent on the sides instead of at the top and bottom. So there seems to have been a production change.

…Quantums 1 on a 1160 and 1 on a 1162…
Can you give a brief discription of the differences and how they compare to mine?

Do they have the Pre-Amplifier module installed (mine doesn't)?

Is there a reason why TV antennas aren't manufactured with 75 ohm impedence instead of 300 ohm?

A folded dipole has a natural impedence close to 300 ohms over a fairly wide bandwidth. Folded dipoles used to feed Yagis and corner reflectors are still closer to 300 ohms than 75, as are the multi-bowtie antennas. And of course 4:1 baluns are much more common than 1:1 baluns, which is an incentive for manufacturers to stick to 300 ohms. Even with a 75 ohm antenna, you can't just feed it from coax without a balun.

Even with a 75 ohm antenna, you can't just feed it from coax without a balun.I remember having a single channel cut yagi back when we had a subscription OTA TV service here in DC.(Super TV-UHF 50) I don't remember it having any kind of balun. The driven element was only half the width of the director and reflector elements.

Can you give a brief discription of the differences and how they compare to mine?

Do they have the Pre-Amplifier module installed (mine doesn't)? Both Quantums I owned had the pre-amplifier module.(1110 & 4248). I thought they all did.:confused:

A folded dipole has a natural impedence close to 300 ohms over a fairly wide bandwidth. Folded dipoles used to feed Yagis and corner reflectors are still closer to 300 ohms than 75, as are the multi-bowtie antennas. And of course 4:1 baluns are much more common than 1:1 baluns, which is an incentive for manufacturers to stick to 300 ohms.Thanks for the explanation.

There was an old A/C powered Channel Master Pre-Amp attached to it and I've seen Pre-Amp modules available on the net. http://www.ultrasatellite.com/product_p/0100c.htm

I watched an episode of Make, a new Do-it-yourself show on my local PBS station and saw them give instructions on how to make an HDTV antenna. For anyone interested, this is the video (http://www.youtube.com/watch?v=0rDPZZzIXIc&feature=channel_page). So I want to build the following antenna (http://cachefly.oreilly.com/make/television/04/DTV_Antenna_FINAL.pdf) seeing as how paying for basic cable to get a compressed signal is pointless. Anyways, my question is whether or not my plan to build the antenna will be in vain since I want to receive some VHF channels. In the instructional PDF, it says that the antenna will easily receive UHF signals, but I want to know whether or not it will work with VHF as well. If not, is there anything I can add to the antenna to make it receive VHF?

They may call it a "digital" antenna (there's no such thing), but it may not work too well on VHF digital channels, because it's a UHF antenna. Rabbit ears would probably work better for VHF channels.

Getting tired of of good designs being demonstrated all wrong (phasing lines way to far appart, between other flaws). Why can people doing videos on the web take the time to validate what they did... See accurate designs and other peoples DIY antennas all over in a sibling forum. See http://www.avsforum.com/avs-vb/showthread.php?p=15480499#post15480499
for quick visual introduction. Search for DB4 or channel master 4221 and PDFs attachments, that should start you on the right foot.

Are you saying that the instructions for the antenna I posted are incorrect?

Are you saying that the instructions for the antenna I posted are incorrect?

Are you PBS or the guy in the video? I don't think so. What I'm saying is that you may just have merely linked a video with good intentions, but this material is a misleading example of how to make a UHF antenna (and you can drop the hdtv prefix the vendors are pushing, it is dumb as commercial bs can be).

I invite readers to search the web for DIY antenna, as stated earlier. I gave also a link of a large forum that will satisfy the most perfectionists.

The antenna would work if you have strong signals in your area but the dimensions are not optimum.

The antenna illustrated is not a Hoverman but what we call a 4-bay bowtie antenna for UHF. The Hoverman, which is very popular on the Canada forum, has a zig zag arrangement of vertical wires.

The 8" elements on each side (we call them "whiskers") are usually about 9" for the new smaller UHF band.

The vertical spacing between each bay is usually about the same as the whisker length, or slightly less. The commercial version by Channel Master is the 4221 with whiskers and vertical spacing at 8".

What channels are you trying for? Go to tvfool.com and enter your zip code, or for greater accuracy, your exact address. Click on save for the combined results of post transition, and post the results from your hard drive as an attachment. The exact address will not show up in the attachment. Or, let us know what the zip code is and we will go to tvfool for you.

If you also need VHF, you would use a separate antenna (like rabbit ears) that is combined with the UHF antenna with a UHF/VHF combiner called a UVSJ.

Experts,

Has anyone compared the Philips MANT940 outside installation to DB2/DB4 or any other similar antennas ?

I got a Philips MANT940 which I could still return (it works fine), so I was wondering if there is anything better for digital reception out there or I should stay with this one.

Thanks,
Laszlo

The antenna illustrated is not a Hoverman but what we call a 4-bay bowtie antenna for UHF. The Hoverman, which is very popular on the Canada forum, has a zig zag arrangement of vertical wires.

The 8" elements on each side (we call them "whiskers") are usually about 9" for the new smaller UHF band.

The vertical spacing between each bay is usually about the same as the whisker length, or slightly less. The commercial version by Channel Master is the 4221 with whiskers and vertical spacing at 8".



I saw that episode and it reminded me of The Myth Busters and the local news programs because it had errors that were obvious to someone who knew something about the topic.

What can you trust from someone like that when the subject matter of their program is something of which you don't have much knowlege?

How can you trust him for anything?

How can you trust him for anything?
Well, it is just a general purpose type show and some of the other crap they make is interesting. Maybe it spurred some to write in or to investigate further.

After all, I do scream at the set when Norm uses an expensive tool when a cheap one would suffice, heh.

After all, I do scream at the set when Norm uses an expensive tool when a cheap one would suffice, heh.

you're just a galoot

Norm's New Million Dollar Yankee Workshop.

Are you PBS or the guy in the video? I don't think so. What I'm saying is that you may just have merely linked a video with good intentions, but this material is a misleading example of how to make a UHF antenna (and you can drop the hdtv prefix the vendors are pushing, it is dumb as commercial bs can be).

I invite readers to search the web for DIY antenna, as stated earlier. I gave also a link of a large forum that will satisfy the most perfectionists.

I'm obviously neither. Your phrasing of your response, was simply confusing, and I apologize if you took my second response the wrong way. I also understand that there is no such thing as an HDTV antenna, but you can't disagree that there are certainly antennas with specific designs capable of enhancing the reception of signals. Hence, I asked the question about whether those designs I linked to were wrong, so I might be able to choose a one that works. I appreciate your Linking to a forum with over 61 pages of various designs, but the fact that there are multitudes of different measurements really didn't assist me in making conclusions about choosing a design. Although, upon plugging in my location to TVFool, I discovered, that there are supposedley no VHF broadcasters in my area, a contradiction to antennaweb. Looks like I'll be just experimenting to see what works best.

I'm obviously neither. Your phrasing of your response, was simply confusing, and I apologize if you took my second response the wrong way. I also understand that there is no such thing as an HDTV antenna, but you can't disagree that there are certainly antennas with specific designs capable of enhancing the reception of signals. Hence, I asked the question about whether those designs I linked to were wrong, so I might be able to choose a one that works. I appreciate your Linking to a forum with over 61 pages of various designs, but the fact that there are multitudes of different measurements really didn't assist me in making conclusions about choosing a design. Although, upon plugging in my location to TVFool, I discovered, that there are supposedley no VHF broadcasters in my area, a contradiction to antennaweb. Looks like I'll be just experimenting to see what works best.

Yeah, the DIY forum is a mess. Far too long and too much blogging. It is so long in fact that I couldn't take the time to point the exact post numbers to help you right away. I would recommend starting from the end and navigate backward.

You may also want to navigate by posters. It shows collaborators like mclapp, rabbit73 and 300ohms which are around often. But your homework (to avoid repeting questions) would be to look for .pdf attachments. I know that's where I found the measurements anyway.

Have fun!

Norm's New Million Dollar Yankee Workshop.

The same reason Bob Vila left This Old House! The projects were "beyond the average viewers means" and then they put that dweeb Steve in there :eek: ...had to bring in Norm to prop up the show....

But hey a Million here, a Million there, pretty soon, you're talking REAL money! :D

and then they put that dweeb Steve in there
Heh, youre not the first person to say that. They might as well have put that gal from Hometime, who is constantly out of breath, in there.

Heh, youre not the first person to say that. They might as well have put that gal from Hometime, who is constantly out of breath, in there.

The tall original blond or the fiesty petite one?? (I liked either one...Didnt the guy marry one of them?)

Yeah, the DIY forum is a mess. Far too long and too much blogging. It is so long in fact that I couldn't take the time to point the exact post numbers to help you right away. I couldn't agree more. Its a shame, really, because there are some phenomenal designs, ideas, and simulations scattered all over the place - buried deeply within multiple threads and across multiple forums. For a newcomer, such as myself, finding those nuggets, and separating the accurate from the inaccurate, is a monumental task - and I'm an experienced electronics engineer!

I have been so impressed with what I've learned from the devoted gurus here. It would be truly remarkable if one of you could start a new thread, where the first post could be maintained and updated with the best designs (or links to them) along with clear and simple explanations of the advantages and disadvantages of each antenna type, common acronyms, and the latest and most accurate information about materials, cables, baluns, combiners, etc. I see the same old questions come up again and again. Directing them to the first post would be so much easier.

EscapeVelocity's indoor antenna thread is a shining example of usefulness to a newcomer. Once you can understand and visualize the basics, you can then dig deeper into the various threads to search for more specifics and opinions on the antenna or topic of interest.

With the digital transition, the interest in OTA has increased tremendously, but many are put off, not knowing where to start, or how to handle the UHF + VHF dilemma.

Gary

I got a Philips MANT940 which I could still return (it works fine), so I was wondering if there is anything better for digital reception out there or I should stay with this one.If the MANT940 has problems with some channels, but if it works for the channels you want at your location, there's no reason to get something else.

I'm considering a CM-2020 for inside my attic. I'm 30 miles north of Baltimore with two ridgelines to deal with. Any hope or should I just forget it? With my highwind location and all the leak problems I've had with my roof I'm not willing to put one up outside.

I'm only interested in pointing to the south.

tnx
jtm

I'm in Chambersburg (67 miles from the Baltimore transmitters) and have two very high ridges (at least 1200'), using a CM3020 on a 40' tower with a pre-amplifier. I'm able to get WMAR, WBAL, WJZ, WUTB, & WNUV.

This link will help you understand what you're up against. Erecting a TV antenna (http://www.hdtvprimer.com/ISSUES/erecting_antenna.html)

OK, this question is: Why does this work?
I have a 91XG with very high directional gain the UHF. This was great for my location until Feb 17th because all stations in the 3 markets that I get OTA were UHF. On Feb 17 one station WILX-DT in Lansing went back their (analog) RF 10 for their digital broadcasts. I was hopeful that the 91XG had enough gain in hi VHF to still get a usable signal. No luck, with the antenna pointed directly at the station - 0%. Oh well, I figure that I must change to a UHF/VHF combo to get this station. Then, to my surprise, while the antenna was pointed roughly 90 deg off (For the Detroit Market) Digital 10 comes in at 70%!

How could this be? Any ideas?

I'm considering a CM-2020 for inside my attic. I'm 30 miles north of Baltimore with two ridgelines to deal with. Any hope or should I just forget it? With my highwind location and all the leak problems I've had with my roof I'm not willing to put one up outside.

I'm only interested in pointing to the south.

tnx
jtmI'm thinking anything in the attic may be a gamble. I would go with nothing less than the Winegard 7697 or 7698. A separate VHF & UHF antenna would be better, but not too easy to work with in most attics. You need every ounce of gain you can get. WBAL-DT 11 will be going back to VHF in June with only a modest amount of power. There will be "many" disappointed WBAL viewers.

You will certainly need a pre-amp also. I recommend the Channel Master 7777 because of it's low noise rating.

Thanks for the inputs. I think I'll put the antenna up and add the preamp if necessary. There will only be a direct connect to the big screen in the FR, no other drops. The figure I posted was "post [6/2009] transition" so I think it should be representative of wbal freq and power.

we seldom get any snow here and this would be facing out the south hip of the roof which clears immediately anyway. probably as good as it gets without going out a gable.

this is strictly an addition rather than a replacement for now so if it is less than perfect, oh well.

jtm

OK, this question is: Why does this work?
I have a 91XG with very high directional gain the UHF. This was great for my location until Feb 17th because all stations in the 3 markets that I get OTA were UHF. On Feb 17 one station WILX-DT in Lansing went back their (analog) RF 10 for their digital broadcasts. I was hopeful that the 91XG had enough gain in hi VHF to still get a usable signal. No luck, with the antenna pointed directly at the station - 0%. Oh well, I figure that I must change to a UHF/VHF combo to get this station. Then, to my surprise, while the antenna was pointed roughly 90 deg off (For the Detroit Market) Digital 10 comes in at 70%!

How could this be? Any ideas?The balun is probably acting as a VHF antenna. I have tried to pick up a low power channel 8(198 watts) with my 91-XG, and it won't decode. Even though it is only 6 miles away, I can't see much difference in signal strength, no matter which way the antenna is pointed. A more distant VHF-12 (23 kw) @ 65 miles out doesn't even move the signal strength meter.

How could this be? Any ideas?
Are you using any 300 Ohm cable? If so, how much 300 Ohm cable are you using?

The pre-amp for my system has about 10' of 300 Ohm between it and the antenna. I've found that the 300 Ohm routing can make or break my DTV reception.

OK, this question is: Why does this work?
I have a 91XG with very high directional gain the UHF. This was great for my location until Feb 17th because all stations in the 3 markets that I get OTA were UHF. On Feb 17 one station WILX-DT in Lansing went back their (analog) RF 10 for their digital broadcasts. I was hopeful that the 91XG had enough gain in hi VHF to still get a usable signal. No luck, with the antenna pointed directly at the station - 0%. Oh well, I figure that I must change to a UHF/VHF combo to get this station. Then, to my surprise, while the antenna was pointed roughly 90 deg off (For the Detroit Market) Digital 10 comes in at 70%!

How could this be? Any ideas?

When the XG is pointed straight at 10 it's not wide enough to be illuminated with the wider wavelength signal.When you turn it to an oblique angle it starts illuminating and becoming and end-fed diploe.Same thing happens with a highband antenna when you turn it nearly perpendicular to the wavefront of a lowband signal.Now you know.

And thanks for the heads-up on WILX moving from 57 back to 10.I'll be on the lookout with the stacked highbanders pointed straight at them. :)

OK, this question is: Why does this work?
I have a 91XG with very high directional gain the UHF. This was great for my location until Feb 17th because all stations in the 3 markets that I get OTA were UHF. On Feb 17 one station WILX-DT in Lansing went back their (analog) RF 10 for their digital broadcasts. I was hopeful that the 91XG had enough gain in hi VHF to still get a usable signal. No luck, with the antenna pointed directly at the station - 0%. Oh well, I figure that I must change to a UHF/VHF combo to get this station. Then, to my surprise, while the antenna was pointed roughly 90 deg off (For the Detroit Market) Digital 10 comes in at 70%!

How could this be? Any ideas?

Yes, "through the back" reception of hi vhf with a uhf yagi style antenna is well known. Roughly, the length of antenna the signal "sees" varies with wavelength for max gain. In other words, channel 13 is more purely "through the back" and the lower channels require progressively more broadside.

I guess that explains why my 91-XG pulled in analog channel 9 through the back so well. IT still pulls in some stations through teh backside like nobodies business, others.. not so much.

Are you using any 300 Ohm cable? If so, how much 300 Ohm cable are you using?

The pre-amp for my system has about 10' of 300 Ohm between it and the antenna. I've found that the 300 Ohm routing can make or break my DTV reception.

No 300 Ohm cable is involved, but there is a VHF/UHF Pre-amp.

When the XG is pointed straight at 10 it's not wide enough to be illuminated with the wider wavelength signal.When you turn it to an oblique angle it starts illuminating and becoming and end-fed diploe.Same thing happens with a highband antenna when you turn it nearly perpendicular to the wavefront of a lowband signal.Now you know.

And thanks for the heads-up on WILX moving from 57 back to 10.I'll be on the lookout with the stacked highbanders pointed straight at them. :)

This makes sense. It is weird that turning this 90 deg from the source makes it work. I think that the reflectors are great for UHF gain, but do absolutely nothing with VHF. In fact, there are some very strong UHF signals exactly in the same direction as RF 10. (WLNS DT and WKAR DT both about 10 miles away). Maybe the UHF Signals overwhelm the signal on 10.

A while ago I ran a simulation on a 91XG boom and driven element only, and it does have some gain on some VHF channels at 90 degrees to the direction it's pointed.

With the digital transition, the interest in OTA has increased tremendously, but many are put off, not knowing where to start, or how to handle the UHF + VHF dilemma.

Gary

Maybe we could help casual readers by not talking about UHF antennas' VHF reception with so much enthusiasm.

Isn't discussing UHF antennas' VHF abilities sort of like discussing the merits of using one model of wrench to drive nails vs another model of wrench to drive nails? If you need a hammer, get a hammer !

(sorry for the lame analogy, but I thought there was a This Old House theme going here.)

Maybe we could help casual readers by not talking about UHF antennas' VHF reception with so much enthusiasm.

Isn't discussing UHF antennas' VHF abilities sort of like discussing the merits of using one model of wrench to drive nails vs another model of wrench to drive nails? If you need a hammer, get a hammer !

(sorry for the lame analogy, but I thought there was a This Old House theme going here.)

some hi vhf (11 and above) if they are strong can be received with a uhf antenna. if a person has a station in that high end of hi vhf with a strong signal then they might need only a uhf antenna. that can lead to a cost savings and also a tremendous size savings and a tremendous maintenance savings (less wind load and mechanically much stronger so they will last longer).

the goal is getting the signal and it doesn't matter so much how you do it. i feel compelled to make a bad analogy too; you don't care what is in the sausage or how it's made you just want to eat it.

some hi vhf (11 and above) if they are strong can be received with a uhf antenna. Some UHF antennas (like my old CM4228) do just fine on quite a few highband VHF channels. I get channels 9, 10 & 13 on mine very well. The stations range from 45 to 70+ miles away.

And it survived our recent ice storms with no damage, unlike many VHF/UHF combos around here which wilted from the weight of the ice, and will have to be replaced.

some hi vhf (11 and above) if they are strong can be received with a uhf antenna.

Some UHF antennas (like my old CM4228) do just fine on quite a few highband VHF channels. I get channels 9, 10 & 13 on mine very well. The stations range from 45 to 70+ miles away.

And it survived our recent ice storms with no damage, unlike many VHF/UHF combos around here which wilted from the weight of the ice, and will have to be replaced.

i was trying to make a conservative statement that would apply to many antennas and lots of people's situation.

good on your antennas. if people had better knowledge of what some antennas could really do and the channel strengths for their area then lots of people might get by with uhf only antennas especially with few final assignments in lo vhf. let your friends and neighbors with busted antennas know about it.

Hey all, I have a question and this seems like the place to post it considering the direction this thread has been going.

I have one of those homebrew DB4 antennas that you may have seen boucing around the web recently. I built it to show my wife how much better one of these would be than our old amplified rabbit ears, but it worked a little too well and now she dosent see the need to spend more on a real one. <sigh>

My problem is with a neighbors ancient truck.

When this truck is running most of my stations get lousy reception. I can hear this truck even at idle from inside my house. Once they leave the area the TV reception clears up almost imediately.

It took me a while to put 2 and 2 together but now that I have I would like to know if there is a way to mitigate this interferance? I'd like the truck to die a quick death on the side of the road, it really is an eyesore. Barring some sort of divine intervention anybody have any ideas?

Oh, and just to irritate some of the people on this thread: My homemade db4 recives the only VHF channel in my area (channel 7) from 30+ miles away just fine.

Hey all, I have a question and this seems like the place to post it considering the direction this thread has been going.

I have one of those homebrew DB4 antennas that you may have seen boucing around the web recently. I built it to show my wife how much better one of these would be than our old amplified rabbit ears, but it worked a little too well and now she dosent see the need to spend more on a real one. <sigh>

My problem is with a neighbors ancient truck.

When this truck is running most of my stations get lousy reception. I can hear this truck even at idle from inside my house. Once they leave the area the TV reception clears up almost imediately.

It took me a while to put 2 and 2 together but now that I have I would like to know if there is a way to mitigate this interferance? I'd like the truck to die a quick death on the side of the road, it really is an eyesore. Barring some sort of divine intervention anybody have any ideas?

Oh, and just to irritate some of the people on this thread: My homemade db4 recives the only VHF channel in my area (channel 7) from 30+ miles away just fine.

most solutions wouldn't be legal.

a store bought antenna will likely be affected just as much in the same location. if either antenna were on the roof both may be affected less.

also high quality shielding on your system might help. cheap single shield coax could let in interference more.

suggest the owner do some maintenance. a bad distributor or bad plug wires could create lots of noise. if it's an antique they may want to use only period appropriate parts. if it's just a beater then they might be willing to upgrade.

good doing on your antenna and its performance.

The easiest thing to try to deal with the truck is to get the best signal and be as far away from the truck as possible. This would mean up high as possible and on the opposite side of the house from the truck location.
John

I thought about upgrading the coax feeding the antenna but I worry that the cheap coax I am using right now might be part of why I get channel 7. :)

At least I was able to figure out what is causing the disruption. That way at least my wifes ire is focused somewhere away from me and my handiwork.

I have seen a few different reccomendations on the bowtie length for the homemade db4s. Some say 7 inch some say 8 inch. Has anyone tried both? What is the typical length on the comercial versions?

Green elf,

Check out the long thread on "how to build a uhf antenna" on this forum. The key factors for DIY 4 bays are whisker length, bay spacing, and phase line spacing. Longer whiskers cause the antenna to tune lower than shorter whiskers. I use a 10 inch whisker by 9.5 inch spacing DIY antenna. This gives me VHF reception and peaks gain just below ch 40. Gain drops quickly after ch 50. It all depends on which channels you are hoping to acquire.

HTH

Rick

Rule of thumb is 36 inches for uhf, 48 for hi vhf, and 60 for lo vhf. 36 would probably still be ok for hi vhf especially if you only need the higher vhf channels say 10 and above. Spacing to prevent interference is measured from nearest metallic elements.

Thanks much.

My problem is with a neighbors ancient truck.

My homemade db4 recives the only VHF channel in my area (channel 7) from 30+ miles away just fine.

Which is it, problem or fine?

I bet that a real VHF antenna would do much better eliminating the interference from your neighbor's truck.

Hey all, I have a question and this seems like the place to post it considering the direction this thread has been going.

I have one of those homebrew DB4 antennas that you may have seen boucing around the web recently. I built it to show my wife how much better one of these would be than our old amplified rabbit ears, but it worked a little too well and now she dosent see the need to spend more on a real one. <sigh>

My problem is with a neighbors ancient truck.

When this truck is running most of my stations get lousy reception. I can hear this truck even at idle from inside my house. Once they leave the area the TV reception clears up almost imediately.

It took me a while to put 2 and 2 together but now that I have I would like to know if there is a way to mitigate this interferance? I'd like the truck to die a quick death on the side of the road, it really is an eyesore. Barring some sort of divine intervention anybody have any ideas?

Oh, and just to irritate some of the people on this thread: My homemade db4 recives the only VHF channel in my area (channel 7) from 30+ miles away just fine.

By ancient, I presume you mean pre electronic ignition.

You might ask if your neighbor also has problems with radio reception in the truck. If the radio (not the CD player) in the truck picks up engine noise, it might need a new condenser (older vehicles had one either inside or on the distributor). It used to be a $3 part and was usually easy to replace. A cracked distributor cap is another possibility but that should be causing problems (usually misfire) that your neighbor would notice when driving.

As someone else has mentioned, cheap or bad plug wires can also emit RF interference. If the plug wires are the problem, the repairs would be a win-win situation for both you and your neighbor. New wires would improve your neighbor's fuel consumption ($$$) and you would get better TV reception.

You might also ask if they are having problems with TV reception at their house. If they are not having problems with their TV, you might ask what their set up is. That might give you some clues unless they have cable.

I thought about upgrading the coax feeding the antenna but I worry that the cheap coax I am using right now might be part of why I get channel 7. :)



Don't worry about that. I'm sure we could find you a coat hanger to use if need be.

Just for fun, I'll throw this out there for you to think about. Consider switching from coax to twinlead all the way to your TV, or at least for the portion of the cable run that is broadside to the offending vehicle.

Properly installed twinlead can out-perform coax on noise rejection. The key there is the "properly installed". It's got to have twists, and it can't be near metal, and oh yes, it can't get wet...etc.

Excuse me now while I duck for cover.

> homebrew DB4 antennas

> When this truck is running most of my stations get lousy reception.

Buy or build more directional antennas, 1 for VHF, one for UHF.
Go for a narrow vertical beam pattern and get the antennas up high if
possible.

Filter out the non-TV frequencies. For UHF you can use a HLSJ diplexor
with the low port terminated (or routed to your FM tuner) to knock down
the stuff below VHF-HI, and a LPF-230 filter to knock down stuff above
VHF-HI. Same deal for UHF except use a UVSJ diplexor and a LPF-700.
Use good quality RG6 quad shield (or the Belden tri-shield) coax.
You might need more than one diplexor in series.

At this point you have done almost everything you can do on your end.
If you still get interference, ask your neighbor to repair the truck,
or report the truck to the FCC.

If the truck always parks in the same place you can try the two antenna
trick to aim a null at the truck. This is above and beyond the call of
duty.

http://www.hdtvprimer.com/ANTENNAS/ganging.html#TAT

Excuse me now while I duck for cover.Too Funny!!:D

By ancient, I presume you mean pre electronic ignition.

You might ask if your neighbor also has problems with radio reception in the truck. If the radio (not the CD player) in the truck picks up engine noise, it might need a new condenser (older vehicles had one either inside or on the distributor). It used to be a $3 part and was usually easy to replace. A cracked distributor cap is another possibility but that should be causing problems (usually misfire) that your neighbor would notice when driving.

As someone else has mentioned, cheap or bad plug wires can also emit RF interference. If the plug wires are the problem, the repairs would be a win-win situation for both you and your neighbor. New wires would improve your neighbor's fuel consumption ($$$) and you would get better TV reception.

You might also ask if they are having problems with TV reception at their house. If they are not having problems with their TV, you might ask what their set up is. That might give you some clues unless they have cable.

Any vehicle causing ignition noise in the FM BC band definitely will have issues with its own internal radio (and I bet they have XMSirius or use the CD!)....If the noise IS that bad, yes, they NEED to change the plug wires AND plugs. The noise is an indication of an ARC.....an ARC is an indication of a broken wire or a cracked plug or both, hence, one cynlinder is not getting enough "fire"....and they are having poor performance (low gas mileage and possible knocking valves)......I would talk with your neighbor and let them know their truck is need of a tune up BAD!!! The plug wires need to be the resistive type which reduces the impulse noise radiated....they have a SERIOUS problem if it is bothering your FM and TV that bad! If the truck is over 100K in mileage, its past due this maintenance anyway!!!

Don't worry about that. I'm sure we could find you a coat hanger to use if need be.

Just for fun, I'll throw this out there for you to think about. Consider switching from coax to twinlead all the way to your TV, or at least for the portion of the cable run that is broadside to the offending vehicle.

Properly installed twinlead can out-perform coax on noise rejection. The key there is the "properly installed". It's got to have twists, and it can't be near metal, and oh yes, it can't get wet...etc.

Excuse me now while I duck for cover.


Twinlead should not be twisted....IF properly jacketed, it can also get wet...but if it gets wet enough to short between the conductors on "open" wire type, it can cause a RF short....Since the noise is RADIATED, switching feedlines will not change anything....it is picked up by his antenna and then down the feedline...be it coax or twin lead....no change would be noticed (open wire ladder line DOES have less loss but its a PITA to work with because it has to be kept away from metal)

Which is it, problem or fine?

I bet that a real VHF antenna would do much better eliminating the interference from your neighbor's truck.

$50 says you're wrong........if the truck is radiating within that channel bandpass, any antenna will pick it up! If a VHF antenna would have more gain, it would only ADD to the problem, not help it....

You can ONLY eliminate noise at the source...you can TRY to cover it up at the other end...but you can never eliminate it there (this from a former TVI/RFI tech for a public utility....been there, know how to fight it)

Twinlead should not be twisted....IF properly jacketed, it can also get wet...but if it gets wet enough to short between the conductors on "open" wire type, it can cause a RF short....Since the noise is RADIATED, switching feedlines will not change anything....it is picked up by his antenna and then down the feedline...be it coax or twin lead....no change would be noticed (open wire ladder line DOES have less loss but its a PITA to work with because it has to be kept away from metal)

Twinlead should not be twisted? Since when? Twisting it is what gives you immunity to differential mode noise. Half-a-twist every 6 to 12 inches, is what many installation guides always said. I'm talking about plain vanila garden variety flat twinlead of course (not jacketed). The kind that anyone in this room more than 50 years old remembers seeing dangling along the outside of a house (maybe their own) in their neighborhood while growing up. It was probably flapping in the breeze, with a couple of stand-offs sticking out from it because they'd pulled out from the house's siding where they'd been installed. Or maybe it was (wrongly) stapled flat to the house's siding.

Yes, agreed, it was a major PITA to be installed and maintained correctly, that's why I worded my previous message the way I did.

I was just trying to bring into the discussion the point that coax (or shielding in general, for that matter) is often not the solution. Addressing the source of the noise is much better, but I wasn't sure if the noise was getting into the system at the antenna, or along the antenna lead.

Which is it, problem or fine?

I bet that a real VHF antenna would do much better eliminating the interference from your neighbor's truck.

The true answer is fine AND trouble, but not the way you are thinking.

The only VHF channel broadcasts on chan 7. That channel now never has less than 80% strength and is not affected by my neighbors truck. The channels that are affected are broadcast channels 15-43. Clearly only the UHF channels are affected.

The antenna is mounted in the attic of my two story home so it's as high as I can get it w/o moving to an outside mount. I know my wife will not go for that. As good as this antenna performs, it's far from being the best looking thing in the world. Repositioning the antenna has had no affect on eliminating the distortion.

Somebody else mentioned pointing a null at the truck but unfortunately that won't work. The truck parks almost in line with my direct line of the broadcast towers. There may be 5 degrees off but not enough for a null to work. I'd loose 90% of my local channels (and 100% of the ones I care about). Also, this happens even when the truck is driving around, not just at idle.

What makes this whole situation both more ridiculous and more frustrating at the same time is that this guy will let his truck idle to warm up for over 20 min at a time! Without the truck all of my channels come in crystal clear at above 75% signal. Not bad for a $5 antenna. It's just this odd thing that I am guessing I'll have to live with.

You know....snowballs are free....and they melt after sitting in a hot tailpipe...just watch them footyprints

You know....snowballs are free....and they melt after sitting in a hot tailpipe...just watch them footyprints

Bananas work better (or so I hear :D )

The true answer is fine AND trouble, but not the way you are thinking.

The only VHF channel broadcasts on chan 7. That channel now never has less than 80% strength and is not affected by my neighbors truck. The channels that are affected are broadcast channels 15-43. Clearly only the UHF channels are affected.

The antenna is mounted in the attic of my two story home so it's as high as I can get it w/o moving to an outside mount. I know my wife will not go for that. As good as this antenna performs, it's far from being the best looking thing in the world. Repositioning the antenna has had no affect on eliminating the distortion.

Somebody else mentioned pointing a null at the truck but unfortunately that won't work. The truck parks almost in line with my direct line of the broadcast towers. There may be 5 degrees off but not enough for a null to work. I'd loose 90% of my local channels (and 100% of the ones I care about). Also, this happens even when the truck is driving around, not just at idle.

What makes this whole situation both more ridiculous and more frustrating at the same time is that this guy will let his truck idle to warm up for over 20 min at a time! Without the truck all of my channels come in crystal clear at above 75% signal. Not bad for a $5 antenna. It's just this odd thing that I am guessing I'll have to live with.

Now this IS odd....only UHF channels are affected?? WEIRD!!!! Are these channels DTV or analog?? (and your WIFE won't allow an outside antenna?? Tsk tsk tsk...cmon MAN....show some----oh never mind....we bachelors, divorced, have it easy I guess ;)

If it were normal ignition noise, it would be worse on VHF and non existant in the U range....possibly made need to get someone with a spectrum analyzer out there to look at it (contact your local ham club; see if they have a TVI committee..if not, call the local power company and see if they have a TVI/RFI guy...if not, call the TV stations! Maybe they can help)...

I would be extremely curious as to what the cause is...and why you only get affected in the UHF range (is it that you only have UHF stations in that range???? Or have you tried looking on other channels in analog? Do you see any effect of his truck on the analog mode?).

Heck if I lived nearby, I would definitely be over with my R2670 service monitor/spectrum analyzer to see what this is...you have my curiosity up!!

Twinlead should not be twisted? Since when? Twisting it is what gives you immunity to differential mode noise. Half-a-twist every 6 to 12 inches, is what many installation guides always said. I'm talking about plain vanila garden variety flat twinlead of course (not jacketed). The kind that anyone in this room more than 50 years old remembers seeing dangling along the outside of a house (maybe their own) in their neighborhood while growing up. It was probably flapping in the breeze, with a couple of stand-offs sticking out from it because they'd pulled out from the house's siding where they'd been installed. Or maybe it was (wrongly) stapled flat to the house's siding.

Yes, agreed, it was a major PITA to be installed and maintained correctly, that's why I worded my previous message the way I did.

I was just trying to bring into the discussion the point that coax (or shielding in general, for that matter) is often not the solution. Addressing the source of the noise is much better, but I wasn't sure if the noise was getting into the system at the antenna, or along the antenna lead.

If this is radiated noise, twisting will not stop the antenna from picking up the noise and the feedline taking it to the rcvr....True, it would stop the LINE from picking up differential noise mode but I dont think this is the case....Also balanced line is just that...BALANCED to already prevent such differential issues....twisting really doesnt help it that much IF the system is balanced already....(btw I am in the 1/2century group...been in broadcasting since my late teens and a ham since age 14)

There IS shielded balanced line (or you can make it out of coax...two parallel runs of coax with the shields tied together and use the center conductors as the "balanced" line works)...and it CAN go next to metal, etc....ahhhhh, what a relief! :)

However, after reading his other post, he has one WEIRD problem.....I dont think its his kind of line :(

The true answer is fine AND trouble, but not the way you are thinking.

The only VHF channel broadcasts on chan 7. That channel now never has less than 80% strength and is not affected by my neighbors truck. The channels that are affected are broadcast channels 15-43. Clearly only the UHF channels are affected.

The antenna is mounted in the attic of my two story home so it's as high as I can get it w/o moving to an outside mount. I know my wife will not go for that. As good as this antenna performs, it's far from being the best looking thing in the world. Repositioning the antenna has had no affect on eliminating the distortion.

Somebody else mentioned pointing a null at the truck but unfortunately that won't work. The truck parks almost in line with my direct line of the broadcast towers. There may be 5 degrees off but not enough for a null to work. I'd loose 90% of my local channels (and 100% of the ones I care about). Also, this happens even when the truck is driving around, not just at idle.

What makes this whole situation both more ridiculous and more frustrating at the same time is that this guy will let his truck idle to warm up for over 20 min at a time! Without the truck all of my channels come in crystal clear at above 75% signal. Not bad for a $5 antenna. It's just this odd thing that I am guessing I'll have to live with.
Does it run rough while he's waiting for it to warm up???
Is your interference worse when he first fires it up???
That could indicate moisture in the distributor burning off.

Can you hear/see whether interference impulses are due to a single cylinder
misfiring (fairly infrequent pulses) or if it's being generated in all cylinders???

If it sounds like a single cylinder then a dirty spark plug, a bad spark wire
or bad distributor cap are suspect. I would disconnect one wire at a time
and if it DOESN'T make the idle rougher, you've found the bad cylinder.

A new distributor cap, rotor, capacitor and (presumably non-platinum)
spark plugs are very inexpensive and spark wire set designed for that
particular vehicle should be readily available and not too expensive.
Perhaps you can offer to help install it for him???

If it's a normal truck, you can do some research and help him avoid
replacing the spark plug set with non-resistor type wires. Resistor type
spark plug wires suppress interference at the source and are available
for even antique vehicles that did not have them originally.
You'll also have to research whether his vehicle is designed to use resistor type spark plugs
with (or without) resistor-type spark plug wires.

I prefer spark plug wire sets that are custom pre-cut for my vehicle, but
universal, fit anything kits are very easy to cut to length and crimp the
distributor connector.

Hot Rod guys (and Hot Rod wannabes) frequently use non-resistor type spark plug
wires along with extremely high voltage (e.g. lethal) ignition systems and very high
compression ratio engines that require special higher-than-pump octane fuel.
If he has a hopped up truck, it's unlikely you'll be able to talk him into
changing the ignition system although he should be keeping it on a trailer
when he ferries it between the drag strip and the aviation gas fuel station.

Since we're already somewhat OT....old engines were designed to use leaded gas,
which lubricated the valve seats. With leaded gas no longer available, gasoline additives
are available to lubricated the valve seats, but knocking can still occur due to reduction
of pump-gas octane (hence the use of AVGas and racing fuel in hot rods).
If this is the REAL reason your neighbor takes a long time to warm up his engine, help
him check into WATER INJECTION systems, which pump a mist directly into the air cleaner.
They're a lot cheaper in the long run than buying gas additives and can be quite effective
on those 60's era muscle cars.

Well guys, there's only one solution left to us.

We have to drop the "This Old House" line of thought...

and switch to "Car Talk".

Clique? Claque? Are you out there, guys?

As far as VHF elements on antennas go, I've seen antennas with them sticking straight out from the main boom (90 degrees), and then others like the one I have, have them sticking out at an angle (maybe 35-45 degrees).

Why the difference with various manufacturers and what advantages, if any, does one orientation provide over the other?

Ok, I'll see if I can answer all the questions...

I don't know if it only affects UHF. What I DO know is that it does not affect the only VHF channels in my broadcast range, which are 7.1 & 7.27 (broadcasting on VHF channel 7) All other 'VHF' channels in my range are all actually broadcasting in the UHF range. It may affect some higher VHF frequencies but I have no way of knowing.

I have not looked at analog in quite some time. Analog signals have always been bad here, so I don't know if the truck affects it. If the truck is idling tomorrow I will test it out. Better scan analog tonight to get a good baseline.

It does not seem to better/worse when it first starts. The interference is present even when he gets home for the day. To be truly scientific about it the interference MIGHT be less when he gets home but he doesn't leave it idling for 20 min then. I see the 'digital static' then I hear the truck, he parks, shuts off the engine and interference goes away. Less than 1 min.

The truck idles rough but doesn't sound to be missing at all. It seems louder in the morning, but that may just be my perception. I doubt this guy is a Tuner or a Hot Rod person. This truck is blue, faded blue, rusty and full of holes. I am more inclined to think this is connected to poor maintenance than special parts.

I'll test the analog signals tomorrow when he leaves. If I get the chance I'll try to flag him down and offer my help to do a tuneup, but I'm not paying for wires and plugs for this guy.

Thanks for the idea too. I think I may call The Car Guys this week with this one. I love their show but being mechanically inclined myself I never really had a reason to call before. I doubt that they would give me more than what I already have but it'd still be fun to have those two guys scratching their thinning scalps over this one.

As far as VHF elements on antennas go, I've seen antennas with them sticking straight out from the main boom (90 degrees), and then others like the one I have, have them sticking out at an angle (maybe 35-45 degrees).

Why the difference with various manufacturers and what advantages, if any, does one orientation provide over the other?

it changes the pattern of reception for the antenna, it would change the distance and angle of good reception

From hdtvprimer.com:
TV LPDAs come in two types: straight and Vee. The Vee type (LPVA) has a very slightly higher gain for channels 7-13. But this author often favors the straight type since it has nulls 90° to each side that can be used to cancel out interference.

$50 says you're wrong........if the truck is radiating within that channel bandpass, any antenna will pick it up! If a VHF antenna would have more gain, it would only ADD to the problem, not help it....

You can ONLY eliminate noise at the source...you can TRY to cover it up at the other end...but you can never eliminate it there (this from a former TVI/RFI tech for a public utility....been there, know how to fight it)

I'll take your $50.

My UHF only antenna (Radio Shack U-100) gets a snowy analog channel 6 that has white dots when the furnace runs and when a light is switched on or off.

My all channel antenna (Winegard HD7015) does not have any white dots from electrical interference on channel 6.

The two antennas are 5' apart on my roof.

The part that you may be missing is that a proper VHF antenna has directivity that will get a stronger signal from the TV station while simultaneously receiving less ignition noise from another direction. Your statement would be correct only if both the DB-4 and the hypothetical VHF only antenna were perfectly omnidirectional on the troublesome VHF channel.

That said; your experience with power line interference is not wrong. It's just that power line interference is usually radiated along the power lines for several blocks. Therefore, the noise arrives at the TV antenna from multiple directions and is much harder to eliminate by the use of directional antennas. The truck interference is more like a point source of noise.

you know....snowballs are free....and they melt after sitting in a hot tailpipe...just watch them footyprints

rofl:)

For goodness sake, shoot the damn truck...

The true answer is fine AND trouble, but not the way you are thinking.

If your neighbor's truck is significantly below your attic you may be able to tilt your antenna up slightly. If you're lucky, you could loose a couple of db of DTV signal but much more of the interference.

If that doesn't work, can you build a second DB-4 and stack it to make the beam shoot over his truck?

Ok, interesting morning...

Truck idled for 20+ min this morning despite being about 50 degrees already...

As I said lat night analog is bad and the truck didn't seem to affect it at all. I checked analog signals on 6,7,9 and 12. In my tests last night I didn't get any of the analog UHF channels well enough to be able to see a quality difference.

I kept an eye out of my house for him to come back out. When he did, I stopped him and explained that I was getting some interference with my TV and that I believed it to be his truck. I then offered to help him give his truck a tune-up and that maybe new wires, rotor and distributor could help reduce the interference I was seeing.

He told me to **** off.

I think I'm back to snowballs and potatoes now.

…power line interference is usually radiated along the power lines for several blocks. Therefore, the noise arrives at the TV antenna from multiple directions and is much harder to eliminate by the use of directional antennas.
How much interference would I get from a 138KV transmission line, approx. 100 yards North of my location, running West to East (264° - 84° Magnetic (True = -11°)).

I also have a higher capacity line (I'll try to get the voltage) running 163° South out of the Sub-Station, then making a right turn to follow I-81 for about a ¼ mile. The Sub-Station is about ½ mile at 304°. There is also a LNG power plant about a ¼ mile North of the Sub-Station.

Do you have any suggestions, beyond a quality installation, to help minimize the interference?

NOTE: Altoona is at 321.5°, Harrisburg is at 52°, York/Lancaster is at 77.5°, Baltimore at 122.6°, and D.C. at 152°.

Well guys, there's only one solution left to us.

We have to drop the "This Old House" line of thought...

and switch to "Car Talk".

Clique? Claque? Are you out there, guys?

Second the motion!!! LOL!!!

He told me to **** off.

I think I'm back to snowballs and potatoes now.

Bananas, man, bananas!!!.....did you not watch "Beverly Hills Cop"??? :) They at least give him time to drive off...but I agree with another poster....time to shoot the truck! :D

How much interference would I get from a 138KV transmission line, approx. 100 yards North of my location, running West to East (264° - 84° Magnetic (True = -11°)).

I also have a higher capacity line (I'll try to get the voltage) running 163° South out of the Sub-Station, then making a right turn to follow I-81 for about a ¼ mile. The Sub-Station is about ½ mile at 304°. There is also a LNG power plant about a ¼ mile North of the Sub-Station.

Do you have any suggestions, beyond a quality installation, to help minimize the interference?

NOTE: Altoona is at 321.5°, Harrisburg is at 52°, York/Lancaster is at 77.5°, Baltimore at 122.6°, and D.C. at 152°.

HV lines like 138KV and above rarely have any arc noise issues...if they do, it doesnt last for long as the arc BURNS and either welds the connection shut (and stops the arc and noise) or blows it open thus requiring a fix (been there, done it)....HV lines USUALLY have only corona noise heard mainly on the lower part of the AM broadcast band...and is only present only as you drive under it.....the corona field is not that strong nor does it radiate as far as an arc does...you should be fine...IF you do have any noise, likely its from distribution lines closer to you OR IF it IS from the HV line, you need to call the company that owns it and have them resolve it quickly.....It will be of benefit to them as well as to you that it is!!! (It could damage equipment and they could get fined by the FCC for the noise if anyone, hint hint :rolleyes:, complains).

HV lines like 138KV and above rarely have any arc noise issues...

Sometimes true. When HV lines make noise it's caused by induction from the HV line into the wires or metal on the support structure. Any loose hardware on the pole or tower is usually what causes the line noise.

It's true that the FCC will cite a power company for interference if they ignore your requests. Yet, you may not get help to receive stations unless you are in their grade B contour.

I know about situations where a blow to a pole from a sledge hammer caused interference to stop. I've seen a street light go out when a pole was hit hard. Another time the interference stopped when a loose guy wire was cut. This guy was crazy, but effective.

Do you know about the trick to use your AM car radio to find line noise?

There IS shielded balanced line (or you can make it out of coax...two parallel runs of coax with the shields tied together and use the center conductors as the "balanced" line works)...and it CAN go next to metal, etc....ahhhhh, what a relief! :) This is a good idea, but the impedance of two parallel runs of coax used as a balanced line, is twice the impedance of a single run, so if you use 75ohm coax, you'll end up with a 150ohm balanced line, and that would be rather lossy in a 300ohm antenna system.

Green-Elf writes:
> He told me to **** off.

Dr Touchtone writes:
> IF it IS from the HV line, you need to call the company that
> owns it and have them resolve it quickly.....It will be of
> benefit to them as well as to you that it is!!! (It could
> damage equipment and they could get fined by the FCC for the
> noise

How does the FCC feel about old trucks?

Green-Elf, are trucks required to pass an emissions test in
your area? The DMV might be interested in this fine truck.

He is probably idling it so long to keep the engine from
stalling when cold. A properly maintained engine doesn't
require this. Prolonged idling is actually hard on engines.

A more directional antenna will be helpful regardless of
what you do about the truck. I only suggested the two
antenna trick as a last resort, you shouldn't need to
do that when the truck obviously needs a tuneup. You can
do the two antenna trick in the vertical axis as well as the
horizontal axis. And as Tower Guy suggested, tilting the
antenna up slightly may help, and will also help avoid dynamic
multipath from passing vehicles. UVSJ diplexors are cheap and
might help.

We are the first distribution point (six houses - two transformers) off this transmission line and it is supported by wooden poles. The other transmission line is constructed of a heavier wood support structure.

I've got a battery powered AM/FM/Cassette radio that I can use. :) What's the best way to do this?

We are the first distribution point (six houses - two transformers) off this transmission line and it is supported by wooden poles. The other transmission line is constructed of a heavier wood support structure.

I've got a battery powered AM/FM/Cassette radio that I can use. :) What's the best way to do this?


The portable AM radio has a bar antenna..it is highly bi-directive at 90degress to the plane of the bar and has deep nulls off the ends of the bar...(the bar runs across the top of the radio going from side to side; hence the longest side of the radio)...you can usually figure out the max/nulls by tuning to a local station and rotating the radio and noting the nulls and max reception in corelation to the actual direction of the stations xmtr site.
Then use it to peak or NULL the noise and use that to take points up and down the road....trianglization will give you the main source of the noise....sometimes you can see a pole and NULL toward it and the noise goes away tellling you that pole is noise source (loose hardware; staples energized to HV and touching ground wire, etc)....When the crews fix the problems, the noise will be gone on that pole no matter which way the radio is pointed...nulling helps as you get closer to the noise source...Also driving around at night and looking for glowing spots on poles will show arcs (especially on dry cool nights when it will arc the most) Rain, wet humid days will kill the arc....

I've got a battery powered AM/FM/Cassette radio that I can use. :) What's the best way to do this?

Do this during the day when there is no skip. Find an unused frequency near the bottom of the AM band. 540-640 works best. Walk around while listening for a loud buzz. The louder the buzz, the closer you will be to the source. Sometimes you can be fooled by a secondary peak a half wavelength (~900') from the main source, so several trips along the power line are prudent.

This morning, I grabbed both of my portable radios, put in a fresh set of six "C" batteries, set the frequency around the mid 600's, then cranked up the treble and volume. I proceeded to walk all through my yard. Very, very quiet. :) I then walked through my house doing the same. WOW! :eek:

I found one of my ionic pro's was radiating a hugh amout of interference. There must be something wrong with it, because the other one was very quiet. There is a lot of interference around the entertainment center.

I found one of my ionic pro's was radiating a hugh amout of interference. There must be something wrong with it, because the other one was very quiet. There is a lot of interference around the entertainment center.
Do you mean that the interference was only coming from the ionic pro that was acting up or do you mean that there was also interfrerence coming from the entertainment center?

I would feel like Columbo doing this.

Do this during the day when there is no skip. Find an unused frequency near the bottom of the AM band. 540-640 works best. Walk around while listening for a loud buzz. The louder the buzz, the closer you will be to the source. Sometimes you can be fooled by a secondary peak a half wavelength (~900') from the main source, so several trips along the power line are prudent.

This morning, I grabbed both of my portable radios, put in a fresh set of six "C" batteries, set the frequency around the mid 600's, then cranked up the treble and volume. I proceeded to walk all through my yard. Very, very quiet. :) I then walked through my house doing the same. WOW! :eek:

I found one of my ionic pro's was radiating a hugh amout of interference. There must be something wrong with it, because the other one was very quiet. There is a lot of interference around the entertainment center.

those things can make RF interference if broken, poorly made or dirty.

also.

Could that interference be from switchmode power supplies (SMPS)? Some "switchers" with poor filtering can radiate a lot of interference.

Most of the interference seems to be coming from the Memorex MVD4541 DVD player / Hi-Fi VCR, with NTSC tuner. You have to be in the room and close for it to register.

We have a fluorescent torchiere lamp that generates massive RFI all the way down to the 40 meter ham band. We don't use it anymore.

Could that interference be from switchmode power supplies (SMPS)? Some "switchers" with poor filtering can radiate a lot of interference.

True! Switchers use squarewave at 120Khz or higher...and that throws harmonics WAY into the HF and even VHF region!! A lot of modern switchers are RF quiet but some stuff is terrible....as my former band director (who was a ham also) would say, sounds like a 400Hz dynamotor generator with no filtering!! EEEEEEEEHHHHHHHHHHWWWWWWWWWWWWWWWWWWWWW!!!! (it hurts to think about it ;)

I only suggested the two
antenna trick as a last resort, you shouldn't need to
do that when the truck obviously needs a tuneup. You can
do the two antenna trick in the vertical axis as well as the
horizontal axis.

I think I'm going to try out adding another antenna below the original one. It's easy enough to do and cheap too. It's also less likely to get me in trouble than anything that bananas, potatoes or snowballs would.

I contacted the local FCC office about the truck and their answer was that there was nothing that they could do about it unless it started affecting a larger area. Nice FCC. Thanks alot.

This is a good idea, but the impedance of two parallel runs of coax used as a balanced line, is twice the impedance of a single run, so if you use 75ohm coax, you'll end up with a 150ohm balanced line, and that would be rather lossy in a 300ohm antenna system.

The impedance of parallel balanced lines is determined by the spacing distance and gauge of wire used.
http://www.qsl.net/co8tw/openline.htm
But I havent seen anthing on using coax for home brewing parallel transmission lines.

The FCC is useless when it comes to the individual. I've complained about issues before and they told me there was nothing that they could do (didn't even know about the reg/law). Sheesh, they were the one who wrote the regs and what one was supposed to do to remedy the situation.

From the FCC Daily Digest:

WE2XXI ADAPTRUM, INC. 0460-EX-PL-2008
New experimental to operate in 174 – 216 MHz, 470 – 608 MHz and 614 – 698 MHz for testing of white space devices.
Mobile: Within State of CA

--------------------------------
Funny, I thought WSDs were limited to UHF only....why are they getting experimental in the VHF range?? There goes any DXng of DTV as we know it.

One more question I had about VHF/UHF directional antennas: For the most part, when I see the large directional UHF/VHF antennas, including on my own, the reflectors are at an angle above and below the UHF elements. However I've seen one or two where the reflectors are off at an angle above and below the VHF elements (meaning they're backwards, in the opposite direction they're normally pointing).

Is that a common configuration or do the people who have their antennas like that have them set up wrong? Would the reflectors do anything for VHF reception?

However I've seen one or two where the reflectors are off at an angle above and below the VHF elements (meaning they're backwards, in the opposite direction they're normally pointing).



Yeah, I think Ive seen that in some of the Aussie antennas. But then again, their toilets rotate backwards when you flush em too, heh.

Seriously, they probably work fine. I havent modeled any, but its just another way for the signal to bounce off of the reflector towards the driven element. Careful spacing probably produces good results.

Alright ! Channel 17.2 in Philly has switched over to the THIS network. Lots of older movies. Listings here : http://www.thistvnetwork.net/

I think I'm going to try out adding another antenna below the original one. It's easy enough to do and cheap too. It's also less likely to get me in trouble than anything that bananas, potatoes or snowballs would.

I contacted the local FCC office about the truck and their answer was that there was nothing that they could do about it unless it started affecting a larger area. Nice FCC. Thanks alot.
Yeah, it's probably a California thing....we can call the SMOG Police....
presuming we don't care about starting a feud with a neighbor....

Yeah, I think Ive seen that in some of the Aussie antennas. But then again, their toilets rotate backwards when you flush em too, heh.

Seriously, they probably work fine. I havent modeled any, but its just another way for the signal to bounce off of the reflector towards the driven element. Careful spacing probably produces good results.
Which Aussie antennas???

You mean like the UK's Triax FM-8:
http://www.dxradio.co.uk/pix.php
or Poland's Dipole A2692:
http://www.dipolnet.com/uhf-vhf_tv_antenna_dipol_dual_39-6-12-21-69_A2692.htm

The driven element has two reflector elements in a "Triad" arrangement,
which provides unexpectedly good F/B Ratio.

W-G PR/HD4400 and PR/HD8800 "reflectors" operate on similar principal,
except another reflector element is directly behind each driven element:
http://www.winegarddirect.com/pdf/spec_PR4400.pdf

I think a lot of these design variations were invented 30+ years ago in order
to look "different" enough to avoid paying someone else costly patent royalities.
Which hopefully have all expired by now.....

Yeah, it's probably a California thing....we can call the SMOG Police....
presuming we don't care about starting a feud with a neighbor....

Yeah know maybe expanding foam into the tailpipe may work...the heat will cause it to expand more so and solidify......EEEHHHHH the fun of it all...

The driven element has two reflector elements in a "Triad" arrangement,
which provides unexpectedly good F/B Ratio.

The "trigon" reflector dates back to 1976 and NBS Technical Note #688.

http://tf.nist.gov/timefreq/general/pdf/451.pdf

Quite a few amateur radio antennas were manufactured with the trigon reflector. I used to have one of these back in the late 80's:

http://support2.overkalix.se/~sm2yer/shack/ant_cc18/cushcraft_2m18.pdf

However, it was found that they didn't really work any better than a single reflector, and fell out of favor.

Ron

Which Aussie antennas???

You mean like the UK's Triax FM-8:

Yeah, like those, except with even more reflectors so that it looks like a backwards corner reflector. I dont have a link right now.


It kind of puzzles me in that design in that they dont typically put a reflector rod directly behind the element also.

As advised on this forum, I replaced my mid-range antenna with a yagi 1713 about 2 ft above an xg91, hooked into a cm7777, on a rotator, on the roof. I have 75 ohm cable from antennas to preamp and to the house. I am about 50-70 miles from transmitters, and the digital strength meter on my television suggests my UHF has improved about 20-30%, i.e. from 30 to 55 on a couple UHF channels. My VHF is a little concerning as channels 9 and 12 are currently broadcasting UHF (47 and 14, respectively), but will switch back to VHF (9,12) post-transition. It does not appear that my 9 and 12 analog reception is improved with the 1713 as compared to my previous mid-range. Unfortunately, I have no digital VHF to test pre-transition.

Thus, any more boost in the UHF is always appreciated as I have a couple of those 20-30% strength that fall out, and my VHF might still need some work. Does anyone have any suggestions to tweak this setup, or something I may be overlooking? I appreciate any advice, the advice I've recieved so far has put me in far better shape than before.

Pre-filter your high band antenna by running its output through the hi port of a hi/lo separator before insertion into the vhf input on the 7777.

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

jns82,

Before installing the 7777, did you:

Open the case and set the VHF/UHF input to "seperate"?

While the case was open, did you check to make wure that the FM Trap was set to "In"?

It is especially important that you have set the VHF/UHF switch to seperate. If it is on "combined", you will not get decent reception on one of the bands, depending on how you attached you coax from the antennas.

Also, others will disagree, but if you can, I suggest you make sure that the YA-1713 is at least 5' away from the bottom of the 91XG's rear screen. This should eliminate any chance of interference between the two antennas. While others will say that 3' is enough, the fact is that the bandwidth of VHF-hi is much longer than this. While your UHF stations may not see interference at this distance apart, your VHF-high stations will most likely be affected.

Just my opinion.

Bill

Bill and cpcat,
Yes, I set the VHF/UHF to separate (as an afterthought, I read the directions and saw this right before I got off the roof), and the FM trap is in. Although I might be able to separate a little further, 5ft is probably not likely with the mast and rotator setup I have. I'll maximize the distance and try the filter on the high-band pass- simple enough-could the filter really make a difference?

thanks,
jns82

Yes. It does for me.

48 inches metal-to-metal is fine for separation for high band. 36 is probably ok too in most situations, especially for the higher hi band channels. 24 inches is pushing it a little. If you can, just experiment and see after your channels turn on.

Hi. I have been told that my situation is difficult and was directed to this Website. I know nothing about antennas, but am looking to make a purchase in the near future. Any antenna and/or equipment suggestions would be greatly appreciated. The house is two stories. My zip code is 56381 and my address specific TVFool data can be found at the URL listed below. Thank you!

tvfool.com/?option=com_wrapper&Itemid=29&q=id%3dc55eddc07a

I have been told that my situation is difficult and was directed to this Website.
Yeah, youre pretty much screwed to get many channels. -8 NM and below channels are very hard to get consistantly.

After transistion, channels 7, 42 at 73 degrees and 10 at 216 degrees are what you can expect. I would get a medium gain VHF/UHF combo antenna and point it at 73 degrees and hope to get 10 at 216 degrees on the backside. If that doesnt suit, reverse the direction and try 7 and 42 on the backside. If you get too high of a gain antenna, backside performance will be less.

I replaced my mid-range antenna with a yagi 1713 about 2 ft above an xg91...

The XG-91 should be above the YA-1713. Like separation, even seemingly minor details like this can have a big impact on signal strengths.

As advised on this forum, I replaced my mid-range antenna with a yagi 1713 about 2 ft above an xg91, hooked into a cm7777, on a rotator, on the roof. I have 75 ohm cable from antennas to preamp and to the house. I am about 50-70 miles from transmitters, and the digital strength meter on my television suggests my UHF has improved about 20-30%, i.e. from 30 to 55 on a couple UHF channels. My VHF is a little concerning as channels 9 and 12 are currently broadcasting UHF (47 and 14, respectively), but will switch back to VHF (9,12) post-transition. It does not appear that my 9 and 12 analog reception is improved with the 1713 as compared to my previous mid-range. Unfortunately, I have no digital VHF to test pre-transition.

Thus, any more boost in the UHF is always appreciated as I have a couple of those 20-30% strength that fall out, and my VHF might still need some work. Does anyone have any suggestions to tweak this setup, or something I may be overlooking? I appreciate any advice, the advice I've recieved so far has put me in far better shape than before.

If your UHF is still not as strong as you like, contact antennas direct and procure a fourth boom section from them for the XG-91 (You'll need an additional middle boom section) and put it on, you'll have to adjust the support bracket to balance the antenna, but it helped ALOT in my situation, I'm now dropout free.

The XG-91 should be above the YA-1713. Like separation, even seemingly minor details like this can have a big impact on signal strengths.

Does this affect the UHF or the VHF signal? I have an XG91 about 3 ft below a Winegard HD8200 and have lost about 20 % SS on UHF since putting up the Winegard. VHF close to 100 % from 50 miles in the mountains & tough terrain.

3' is a bit too close. 3-1/2' is the minimum recommended separation. You can mount either one on top, but the 91-XG is so light, it usually works best at the top. Sometimes those few extra feet help with the more fickle UHF frequencies. At 3-1/2', I haven't noticed any degredation in UHF performance with my system.

Are you trapping you FM? You have 2 FM stations within 10 miles. WAMC-90.3 @ 10 kw may be problematic, even with the trap engaged.

I always hear that 3' or 3-1/2' is enough seperation. the fact is that you should always strive to keep your antenna distance at least one wavelength apart. In the case of a VHF-hi antenna and a UHF antenna, this is about 5'-4" for channel 7. To be safe, I would strive for 6' or even a touch more. I mounted mine nearly 7' apart (from the bottom of the 91XG rear screen to the top of the psp.1922 reflector). I have no interference problems.

If you are using an older "all channel" 2-69 antenna, it may need to be a much greater distance, as that antenna will pull in channel 2, with its HUGE wavelengths. An FM antenna also needs more room.

On the other hand, you can mount UHF antennas as close as about 3' apart with no problems.

Bill

3' is a bit too close. 3-1/2' is the minimum recommended separation. You can mount either one on top, but the 91-XG is so light, it usually works best at the top. Sometimes those few extra feet help with the more fickle UHF frequencies. At 3-1/2', I haven't noticed any degredation in UHF performance with my system.

Are you trapping you FM? You have 2 FM stations within 10 miles. WAMC-90.3 @ 10 kw may be problematic, even with the trap engaged.

Speaking from experience, 36 inches separation b/w nearest metallic elements won't likely present a problem with uhf or hi vhf.

For some, adding separation isn't much of a problem. In that case, use rule-of-thumb type separation just to be safe: 36, 48, 60 for uhf, hi vhf, and lo vhf respectively.

For others, i.e. using a rotator without a bearing or if there is limited mast space, the installation may require narrower spacing. In most cases, it's ok to cheat a little and still not suffer noticeably with performance.

Yeah, I think Ive seen that in some of the Aussie antennas. But then again, their toilets rotate backwards when you flush em too, heh.

When viewed from the right perspective, from down under, they flush clockwise.....just like here.

Does this affect the UHF or the VHF signal? I have an XG91 about 3 ft below a Winegard HD8200 and have lost about 20 % SS on UHF since putting up the Winegard. VHF close to 100 % from 50 miles in the mountains & tough terrain.


Yes the XG91 should be above the hd8200. For a pretty good explaination of what is going on, consult http://www.ifwtech.co.uk/g3sek/stacking/stacking2.htm
or http://www.tvantenna.com/support/tutorials/combining.html


In reality, it all ends up being typical rf black magic. Eith have a field strength meter or someone inside the house tuning in stations to detrmine the best set up. It is much easier if there are no coexisting or adjacent channels.

When viewed from the right perspective, from down under, they flush clockwise.....just like here. HAHA! Good one!

Here are pictures of my "Dry Bearing" setup for my antenna tower. :D

I'll be fine tuning my setup as the Summer progresses. :)

I made the antenna move to the rotor yesterday. :)

3' is a bit too close. 3-1/2' is the minimum recommended separation. You can mount either one on top, but the 91-XG is so light, it usually works best at the top. Sometimes those few extra feet help with the more fickle UHF frequencies. At 3-1/2', I haven't noticed any degredation in UHF performance with my system.

Are you trapping you FM? You have 2 FM stations within 10 miles. WAMC-90.3 @ 10 kw may be problematic, even with the trap engaged.

First thanks for all the replies.

I'm not sure if I'm trapping FM, but I don't think so. If I do trap, will that affect my FM reception. I use the same antenna setup for FM reception.

If you are using an older "all channel" 2-69 antenna, it may need to be a much greater distance, as that antenna will pull in channel 2, with its HUGE wavelengths. An FM antenna also needs more room.

My new HD8200 does pull in an almost watchable analog signal from Utica, NY which is about 80 - 90 miles west of me. My mast is 10 feet on a tripod on my roof. The 8200 is on top and the 91 about 3 ft below it. I could add a 5 ft section of mast to the top and put the 91 up there. I hate to lower the antennas at all, but I am a bit nervous about going too high because we do see 60 MPH winds around here at times.

In reality, it all ends up being typical rf black magic. Eith have a field strength meter or someone inside the house tuning in stations to detrmine the best set up. It is much easier if there are no coexisting or adjacent channels.

I usually have my wife watch the SS meter on the TV and we talk with 2 way radios to figure aiming. At my location I get no UHF SS when aimed at the antenna farm, but get 60 - 70 % aimed at the moutain behind my house about 160 degrees (almost opposite) direction. The problem is that I can't keep the signal locked except under optimal conditons. Sunny, no wind. Am hoping to increase the SS just a bit. Soemtimes the dropouts just make the channels unwatcheable. With the Winegard VHF is rock solid with 90 + SS. One of the UHF channels is going back to VHF 6 after June 12 so I will only have 3 stations on UHF after that with 3 on VHF (6, 7 & 12)

FM Traps are meant to reduce FM signals by large margins. I use a seperate FM antenna for my stereo.

I did some calculations and found that as long as your local DMA isn't using VHF-Lo for DTV or LPA's, your spacing can be as close as 32.16". This is also the minimum spacing between the bottom of the lowest antenna elements and your roofline/tower.

Higher and wider is alwyas better, unless you are ganging. :)

UTube 4-Bay Bowtie vs CM-4221, mclapp's M-4 and one more (unknown) 4-Bay.

Since I was curious re antenna performance, in the DIY UHF Antenna thread, I posted
a link to 4nec2 simulation studies I conducted on the UTube antenna (which has NO Reflector)
and, for comparison, three additional 4-Bay Antennas, presuming NO Reflector:
http://www.avsforum.com/avs-vb/showthread.php?p=15947660
Perhaps some of you would like to join the discussion.....

NEC predicted the UTube 4-Bay to have low Raw Gain on the lower channels and very poor
SWR throughout the rest of the New UHF band. And Hi-VHF SWR was sky-high....
Checkout mclapp's M-4 (or M-8) instead.....

I did some calculations and found that as long as your local DMA isn't using VHF-Lo for DTV or LPA's, your spacing can be as close as 32.16". This is also the minimum spacing between the bottom of the lowest antenna elements and your roofline/tower.



Thank you. You answered a question I was about to ask. I keep reading about spacing antennas based on the wavelengths of the channels that the antennas are designed to receive, but it seemed to me that you should only have to space them based on the channels that you intend to receive.

That's vertical spacing, not horizontal. I'd double that for horizontal.

I'm not sure if I'm trapping FM, but I don't think so. If I do trap, will that affect my FM reception. I use the same antenna setup for FM reception. Too much FM gain can cause issues on weaker TV stations. Go to www.fmfool.com and enter your exact address or coordinates. This will give a better idea if it is a possible cause of your lowered UHF readings.

Here are pictures of my "Dry Bearing" setup for my antenna tower. :D

I'll be fine tuning my setup as the Summer progresses. :)

Looks ok.Couple comments,though.

Did you put any lube on the mast where it goes thru the apex pipe collar?As time goes on it will corrode and cause problems.Looks to be a fairly snug fit.

If I'm seeing white coax,that's a no-no.Sun will eat it up in a year,or two.

And so,how's the performance?

No lube, since it's a temporary setup, until I get the longer pipe.

Yes, it's white and I'll be replacing it when the longer pipe gets installed (it's at length now).

Works great! The winds today have the whole tower swaying a bit and the antenna is causing some additional motion on the pipe. I think it would be a little more stable, if I move the rotor to the bottom of the mounting pipe, and get some more weight and bracing on the center pipe.

There's a small amount of play between pipes. if you go to the hardware store and take a small stub of 1" galv and a small stub of 1½" (or did I use 1¼"), slide the 1" inside the other, you'll see what I mean.

I'm keeping an eye out for some sort of neoprene material to use as a floating seal on the topside.

3' is a bit too close. 3-1/2' is the minimum recommended separation. You can mount either one on top, but the 91-XG is so light, it usually works best at the top. Sometimes those few extra feet help with the more fickle UHF frequencies. At 3-1/2', I haven't noticed any degredation in UHF performance with my system.

Are you trapping you FM? You have 2 FM stations within 10 miles. WAMC-90.3 @ 10 kw may be problematic, even with the trap engaged.

10KW ERP at what HAAT??? 10KW at 10 miles?? Doubt its causing issues...I have 100KW at less than 10 miles...not a problem.....FM trapping is normally used when you have a 88-89MHz FM within eyeshot....(2-5 miles) or your antenna is pointed right down its throat...at 10 miles sep, the signal levels drop off enough...

First thanks for all the replies.

I'm not sure if I'm trapping FM, but I don't think so. If I do trap, will that affect my FM reception. I use the same antenna setup for FM reception.


Yes it will.....If you arent looking directly at a FM antenna farm (like the Sr Road tower in Houston with 9 FMs all running 100KW on it) or you dont live in the shadow of a FM tower, you should be fine.....I have three 100KW FMs within 15 miles of me...my CM7777 doesnt overload on them at all...I have a 88.1 18 miles to the west of me...if I swing the antenna that way, I dont see any problems on TV6....which is all the FM trap usually helps....my spectrum analyzer shows a nominal signal off the FM and no overload...now IF I lived within a few miles of the FM, yep, I could be in serious trouble...like the folks there who had filters put on their TV antennas by the FM to get rid of the overload...direction and distance makes a difference. I hardly ever use the FM trap.......

Has anyone found a frequency response graph for the HLSJ and UVSJ
diplexors used as high-pass filters? Something similar to this
FM trap:
http://www.kyes.com/antenna/interference/fm/frqrsp.jpg

Yes it will.....If you arent looking directly at a FM antenna farm (like the Sr Road tower in Houston with 9 FMs all running 100KW on it) or you dont live in the shadow of a FM tower, you should be fine.....I have three 100KW FMs within 15 miles of me...my CM7777 doesnt overload on them at all...I have a 88.1 18 miles to the west of me...if I swing the antenna that way, I dont see any problems on TV6....which is all the FM trap usually helps....my spectrum analyzer shows a nominal signal off the FM and no overload...now IF I lived within a few miles of the FM, yep, I could be in serious trouble...like the folks there who had filters put on their TV antennas by the FM to get rid of the overload...direction and distance makes a difference. I hardly ever use the FM trap.......

I would suspect that the closest FM station in the direction my VHF antenna is pointed is probably 40 miles or so. My UHF is pointed in almost the opposite direction to get a signal bounce off the mountain behind me, but I am not sure what FM stations are that way. Town (Pittsfield, MA) is generally in that direction about 8 miles southeast as the crow flies, but the FM stations there are pretty weak. FM from Albany, NY (about 45 miles west) is much stronger and easier to pick up here on the antenna. One of our stations will be going back to VHF 6 on June 12th. So I guess I will have to take care of my spacing before then. Lots of snow on the roof right now so this will have to wait a while.

10KW ERP at what HAAT??? 10KW at 10 miles?? Doubt its causing issuesThat is why I asked him to run the FM FOOL. I don't know how close he is. Just using the zip code shows 10 miles. The station in question has it's transmitter located well east of Albany, much closer to the Hancock area.

http://www.radio-locator.com/cgi-bin/info?call=WAMC&service=FM

Has anyone out there tried the ganged antenna method as described on the HDTV Primer site? "http://www.hdtvprimer.com/" Had any luck? If one is combining two of the
DB8 Bow tie Antennas (side by side), how is the distance between them measured? Do I measure mast to mast or between adjacent sub bow tie arrays?

I have been playing around some and have been able to pull in some distant stations only to loose one nearby. Trade-offs, Trade-offs.

If I put two antennas on a combiner, and don't want them to interfer witheach other, how far apart do they have to be ? It has been too long since I took that electromagnetics class.

That is why I asked him to run the FM FOOL. I don't know how close he is.

Davird_Jr has a big hill between him and WAMC-FM.

I've finalized an evaluation of interference I'm getting on RF 7 (WJLA-TV) analog. I'm getting FM interference from two stations (89.1 (WGMS) and 90.5 (WCRH)). I've got the FM trap active on both my pre-amp and DA.

The stations are 14.4 miles and 20.5 miles with .9KW and 10KW transmit power. My receive level is -43.8 dBm and -32.4 dBm at 153° and 238° magnetic. WJLA-TV is 70.7 miles, 164° magnetic, 2-edge, -95.8 dBm reception.

What can I do to resolve this interference before WJLA-TV (RF 7) becomes WJLA-DT (RF 7)?

Antenna: CM3020 - Pre-Amp: CM0264DSB - DA: Trunkline 20-TDA25 - AGL: 40'

What can I do to resolve this interference before WJLA-TV (RF 7) becomes WJLA-DT (RF 7)?Get rid of that huge full band antenna. You won't need VHF-LO after the transition. That should eliminate the need for any additional trapping.

What can I do to resolve this interference before WJLA-TV (RF 7) becomes WJLA-DT (RF 7)?

Antenna: CM3020 - Pre-Amp: CM0264DSB - DA: Trunkline 20-TDA25 - HAAT: 40'

Why do you need a preamp and a Trunk amplifier? It's likely that the trunk amp is overloading.

I'm currently evaluating different antennas and looking to replace the DA with a CM3412. I wish I had known about the Antennas Direct CPA19 (http://www.solidsignal.com/prod_display.asp?PROD=CPA19), before I had purchased my CM pre-amp. I may have purchased it instead.

Without the DA, I don't get WMAR, WJLA (marginal now), WGAL, WUSA, WBAL, WDCA, WNPB, WUTB, WBFF (marginal now), and WGCB.

I'm not able to get WRC-DT, WLYH-DT, WHP-DT. WHTM-DT, WETA-DT, WITF-DT, and WDCW-DT.

FYI: Ke Nist posted NEC SIM results for new DB-8 and CM4228HD:
http://www.hdtvprimer.com/ANTENNAS/TemporaryPage.html

He found problems (mostly in the new DB-8) and recommended some fixes....
mostly going to a separate combiner.

Without the DA, I don't get WMAR, WJLA (marginal now), WGAL, WUSA, WBAL, WDCA, WNPB, WUTB, WBFF (marginal now), and WGCB.




By any chance, is the DA serving as an attenuator for those channels ? I dont have your TVFool handy.

Davird_Jr has a big hill between him and WAMC-FM.

I checked my signal levels yesterday and for whatever reason I am getting 20% better signal strength on 10-1 than on 6-1. 6-1 seems to be most susceptible to dropouts recently, other than 45-1 which almost never comes in anymore. Are they doing something differently in the past few months? Bad weather drops all of the UHF stations though. VHF remains rock solid no matter what the weather with my HD8200, usually giving me SS between 90 & 100 %. UHF continues to drive me crazy.

Why do you need a preamp and a Trunk amplifier? It's likely that the trunk amp is overloading.

FM should NOT be causing a problem on TV7....BUT you may have a mix of A+B with the two freqs you mentioned which would be 179.6..TV7 is 174-180MHz so the mix is right at the upper edge close to the aural carrier...the amps could be picking up the mix and amplifying them as intermod mix..and that could be your problem...DO you need that much gain for the TV?? Get tunable FM traps and notch the two freqs (not one trap but two tunable traps...get rid of the mix)....dont trap in the amps....NOTCH both FMs before the amp and that should work....also see about knocking down all your TV gain.....you could be overloading something....

systems2000,

The right antenna(s) will solve all many of your reception woes. I agree with Rick's suggestions, but would also replace the 3020 with a Winegard YA-1713 for VHF. Your concerns with FM should not be a concern once you eliminate the VHF-LO capable antenna. You will reduce a lot of wind load also.

I'm really wondering whether you have much luck with 11 & 13 out of Baltimore, post transition. Unfortunately, the low power(channel 11 @ 5 kw) and directional signal (channel 13 favoring areas to the east) may leave viewers in your area in the dark. I'm hoping the FCC will address these issues.

Channel 12 @ 23 kw from your area makes it here just outside DC just OK @ 65 miles, but it does hiccup occasionally.(UHF is much better) I was expecting better with VHF-HI, but am a bit dissapointed. I think the VHF digital power allotments will need to be re-evaluated.

FM should NOT be causing a problem on TV7.....

Channel 7 runs from 174-180 mhz. The second harmonic of 89.1 MHz is 178.2.
It falls within channel 7. An overloaded amplifier creates the second harmonic.

A Winegard FT-7500 or FT-7600 installed before the DA might solve the problem.

I disagree. :mad:

This throws off the entire gain pattern of the antenna.

I did all of this stuff, and determined it was NOT worth it. I even added 3 additional sections. You end up with a sagging antenna that is worse. :eek:


If your UHF is still not as strong as you like, contact antennas direct and procure a fourth boom section from them for the XG-91 (You'll need an additional middle boom section) and put it on, you'll have to adjust the support bracket to balance the antenna, but it helped ALOT in my situation, I'm now dropout free.

By any chance, is the DA serving as an attenuator for those channels ? I dont have your TVFool handy.
I completely removed the DA and attenuators.

FM should NOT be causing a problem on TV7....
That's what I thought.
BUT you may have a mix of A+B with the two freqs you mentioned which would be 179.6..TV7 is 174-180MHz so the mix is right at the upper edge close to the aural carrier...
WJLA audio is completely wiped out by the audio from both FM stations. They're both coming through at the same audio level.
the amps could be picking up the mix and amplifying them as intermod mix..and that could be your problem...DO you need that much gain for the TV??
Yes. It doesn't matter if the DA is in the system or not.
Get tunable FM traps and notch the two freqs (not one trap but two tunable traps...get rid of the mix)....dont trap in the amps....NOTCH both FMs before the amp and that should work....
The pre-amp has a tunable FM trap. I'll see if I can eliminate some of the problem with it. I think I'll get a tin can and shield the pre-amp while I'm at it. Any recommendations on tunable FM traps?

http://www.winegarddirect.com/cview~c~Traps.htm

The right antenna(s) will solve all many of your reception woes. I agree with Rick's suggestions, but would also replace the 3020 with a Winegard YA-1713 for VHF.
I've been looking at the YA-1713 for my 7, 8, 9, 10, 11, 12, 13 channels. Right now I like using the CM3020, so that I can find my problem areas and best placement. Does anyone know where I can get a Televes DAT-75? I like the Gain/Beamwidth, and Front-to-Back Ratio. I've been mulling over the idea of mounting and ganging four of these pointed at York/Lancaster, Baltimore, D.C., and Altoona, while my SBGH/DBGH is used for Hagerstown, Martinsburg, Winchester, & Front Royal.

I thought I read somewhere that the DTV tuners are supposed to be really good at filtering out secondary signals. I'm thinking there's going to be a difference between multipath and antenna ganging. I'm going to test this theory, with my CM3020 and SBGH/DBGH this weekend.

People have found the 91XG outperforms the overspec'd DAT-75...

A Winegard FT-7500 or FT-7600 installed before the DA might solve the problem.
Before the DA or the pre-amp?

I'm assuming I can use just one FT-7600, since it's two-stage. Unfortunately, the FT-7600 has 75 Ohm input and output connections and will have to be after the pre-amp.

Before the DA or the pre-amp?

I'm assuming I can use just one FT-7600, since it's two-stage. Unfortunately, the FT-7600 has 75 Ohm input and output connections and will have to be after the pre-amp.

In your case it may work before the DA. Usually an FM trap needs to be before a preamp. Note that the FT-7600 must be specifically tuned to 89.1 after you buy it.

Got up on the tower this morning (with the wife in front of the TV and using walkies) and adjusted the 0264DSB FM trap. WJLA is now coming in just as good as WUSA and better than WTTG, WDCA, WRC, and WETA (in that order). I don't get WDCW or WPXW.

I'm happy I didn't have to spend more money on that issue. I feel for those who will not see this problem, when the analogs go dark.

I ran across an inexpensive meter for (http://www.tvaerials.com/product.aspx?productid=2158)DVB-T (http://www.tvaerials.com/product.aspx?productid=2158) signals and I'm wondering when we'll see one for 8-VSB. I don't see how a home owner will be able to get maximum performance on their own without something like that, or better yet - a spectrum analyzer.

WJLA audio is completely wiped out by the audio from both FM stations. They're both coming through at the same audio level.



When you stated that, it confirmed it was a MIX and not overload by one station....otherwise, you would have heard only ONE and not both...by your next postings, I see you got rid of it with the tunable notch...CONGRATS!!!

Yeah, a simple RF meter for home use would be a great thing for consumer use...of course those of us with a spectrum analyzer can make a little extra money on the side with it :rolleyes:

> a simple RF meter for home use would be a great thing for
> consumer use

Some tuners provide actual signal strength, (and a seperate
signal quality number,) so that is easy enough. Information
about multipath and interference are easy with NTSC, but not
so easy with ATSC/8VSB.

Has anyone looked into the TECH version of the HDHomeRun tuner?
Does it provide anything useful for debugging bad reception?

Even with the meters included with ATSC devices, it's still a two man job. With a fast response hand-held meter, one person could do the job a lot easier. Spectrum analyzers would be the best, by a long shot.

Got up on the tower this morning (with the wife in front of the TV and using walkies) and adjusted the 0264DSB FM trap.
So you just screwed it in and out and observed ? I havent adjusted mine, and no directions in the box, of course. The only thing I found on the web on adjusting it, was to hook it up to an FM antenna and radio (or rabbit ears adjusted to FM frequencies) and adjust for the lowest performance on the station(s) you want to block.

Open up the case, you should see a slotted post identified as the "Tunable Trap." It is a Variable Capacitor (http://en.wikipedia.org/wiki/Variable_capacitor). You'll need a non-conductive tool that resembles a screwdriver tip (a stiff flatten straw will do). While someone is watching RF channel 6 or 7, rotate the capacitor until you get the best picture/audio possible.

Open up the case, you should see a slotted post identified as the "Tunable Trap." It is a Variable Capacitor. You'll need a non-conductive tool that resembles a screwdriver tip (a stiff flatten straw will do)
Yeah, I saw that variable cap and have plenty of TV/Radio IF coil screwdrivers on hand and a FRS/GMRS Motorola walkie talkie that Ive never used, heh. That may be the way to go, because in my situation with a channel 6, its going to have to be a very close adjustment tweak.
I was and am waiting for the post transistion to happen first though.

Some tuners provide actual signal strength, (and a seperate
signal quality number,) so that is easy enough. Information
about multipath and interference are easy with NTSC, but not
so easy with ATSC/8VSB.

Yep. Earlier in this thread, rabbit73 posted good data of comparing the output of his pricey meters against the Apex DT502. (and hopefully against the Sansonic FT300 soon). It can be used as kind of a reference source for the output of the signal quality and strength meters of those CECBs.

I've been looking at the YA-1713 for my 7, 8, 9, 10, 11, 12, 13 channels.

Assuming you don't need low band, use a lo/hi separator (use the hi port) as an FM trap. Place it on the antenna's output before the preamp input. It will do a much better job. No tuning required either.;)

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

I was and am waiting for the post transistion to happen first though.
If you wait until after the transition, you will not be able to see how it affects RF 6 (unless you have a spectrum analyzer). I did my adjustment while viewing WJLA-TV, not WJLA-DT.

So hook it up to an FM antenna and radio (or rabbit ears adjusted to FM frequencies) and adjust for the lowest performance on the station(s) you want to block.

Some component receivers have a signal strength meter. Tune for lowest signal.

Here is my setup:
40' antenna pole with a 91xg at the top of the pole
18" below that a CM7777
18" below that a Y10-7-13

My zip code for TVFool is 79065. According to them PBS (8 real and 2.1 virtual) and CBS (9 real and 10.1 virtual now-after the transition 10 real and 10.1 virtual) are VHFhi.
ABC (right now 23 real and 7.1 virtual) will join them after the transition and be VHFhi (7 real and 7.1 virtual)

My UHF antenna works well, but the VHF antenna does not. The PBS station rarely locks in-- maximum signal has been 26. Still can watch it with a 26 signal. CBS is better at ~ 50-60.

When we installed the CM7777 we changed the VHF switch from combined to separate. Every thing else is default.

Now the problem:
The PBS and CBS stations have a decent signal usually before 11AM and after 11PM. Between 11AM and 10-11PM if we get a signal, it is full of drop outs and pixelations---basically unwatchable.

The antenna stands beside our 2 story house with a very very steep roof. It is extremely hard to get to. Our option is to lay the tv antenna down to work on it.

What could be causing the kind of problem I am describing? Any advice is appreciated and welcome.

Sorry for the long post TIA

Sandy

What could be causing the kind of problem I am describing? Any advice is appreciated and welcome.

Sorry for the long post TIA

Sandy

The biggest issue is that those signals are 100 miles or greater away. Additionally, the CBS has co-channel interference from your local NBC station. Consistent drop free reception at that distance especially during day time hours is probably not a realistic expectation.

We are just 55 miles away from the towers

We are just 55 miles away from the towers


Not according to tvfool for zip 79065.:confused:

The PBS, CBS, and ABC you mention are all >100 miles away.

Gosh, we must not be looking at the same thing. Here is the link listed on th tvfool page


If you would like to share these results with others, this page can be referenced as:
http://www.tvfool.com/?option=com_wrapper&Itemid=29&q=id%3de288f9b2df

TVFool does report a distance of about 100 miles if you give it just Zip code 79065. That code must cover a large area. :p

I also looked at your TV Fool zip code location. Both stations are indeed over 100 miles away, plus you already have a local CBS and PBS channel. The two channels in question are both in a distant market, from what I see.

Personally, I would get out my compass and aim both antennas to 184 degrees (4 degrees west of due south). I All of your digital stations will be UHF after the final transition, with the exception of KCBD NBC 11, which is obviously VHF-Hi. You also will be able to receive a ton of lower power analog channels from this direction.

I am lucky enough to receive several different markets, and I know that you are most likely hoping to do the same, but I can tell you that I use a pair of Funke psp.1922 VHF highbanders, and I would have a very hard time picking up the two distant VHF stations you are looking for. These Funkes are between 4 and 5db more sensitive than the excellent YA-1713 and are able to pick up a signal that is only about 1/3 as strong as what the 1713 can reliably receive, yet I am fairly certain that I would be unable to receive the channels in question 24/7.

One other thing...I would try to get a little more seperation between the antennas. Many people here will tell you that 3' is plenty, but I can tell you that you really want to be at least one wavelength apart. Since the lowest channel you can reliable receive is channel 11, I would try to get at least 4' (or better yet...4'-6") between the lowest part of the 91XG rear screen and the top of the YA-1713. This will eliminate any interaction between the two antennas.

Good luck.

Bill

I posted the link to my tvfool location. I live in Pampa, TX.....~55 miles from the towers. The local stations I am trying to get are
KFDA local CBS - 3 sub channels
KVII local ABC - sub channel CW
KACV local PBS - 1 sub channel
KAMR local NBC - sub channel is MyNetwork
KCIT Local FOX

Sorry if I confused everyone by just giving my zip. But I should be able to get these stations. I can get the analog signals

> with a channel 6, its going to have to be a very close adjustment tweak

If you have a NTSC on channel 6 now, do your FM trap adjusting now,
while you have an easy way to see what it does to channel 6.

With a channel 6, try a 95-108 MHz FM trap. The inexpensive ones
are only 20 dB so get at least 2. Or get a better one from
http://www.tinlee.com/

The variable cap is presumably a notch filter. With 95-108 gone
you can use the notch filter on a station in the 88-95 range.

You may or may not be able to use a 88-108 MHz FM trap. Try one but
be prepared to take it back out if it hurts channel 6 too much. I
currently have a NTSC channel 6 and a strong 88.3 FM. One 88-108
trap helps, but using 2 of them does a real number on channel 6.
If channel 6 was staying around I'd look into a better antenna
and higher quality filters.

You could also consider a single channel antenna for channel 6,
especially if that will be your only VHF-LO station.

I should be able to get these stations. I can get the analog signals

Analog signals are MUCH easier to receive than digital signals,
especially if the there are hills and/or trees.

We can pick up several analog stations with rabbit ears.
We cannot pick up any digital stations even with a top-rated outdoor antenna.
http://www.avsforum.com/avs-vb/showthread.php?t=369015&page=135

====snip====
I ran across an inexpensive meter for (http://www.tvaerials.com/product.aspx?productid=2158)DVB-T (http://www.tvaerials.com/product.aspx?productid=2158) signals and I'm wondering when we'll see one for 8-VSB. I don't see how a home owner will be able to get maximum performance on their own without something like that, or better yet - a spectrum analyzer.
Are there DTVs that DON'T have a signal quality meter????
If not, there's a good incentive to get a CECB coupon box....

Here's a link with a bigger picture and Labgear 27866R Spec Sheet:
http://www.chsinteractive.co.uk/electrical-components/tools-service-aids/test-equipment-spares-accessories/testers/meter-digital-terrestrial-dvb-t-signal-finder-led-level-indicator-and-built-in-amplifier-labgear.htm
http://www.chsinteractive.co.uk/pdf_data/27866R.pdf
And if you prefer to pay in pounds vice euros:
http://www.amazon.co.uk/exec/obidos/ASIN/B001GHM1K8/microsoftcouk-21/ref=asc_df_B001GHM1K8322496

Since it doesn't have any frequency selection or display capability, it must
be a simple, full-band energy detector, so modulation type doesn't matter.
Should work with NTSC, ATSC, PAL, DVB-T, ad nauseum.

It allows you to rotate the antenna to maximize received power on whatever
happens to be the STRONGEST received channel. Unfortunately, if you have
a strong local station, it wouldn't help aligning antenna toward a weak station.

But if it meets your needs, consider giving them your credit card number....

======================================
The Digiair Pro displays individual channel signal strengths, but isn't as
sensitive as a professional quality signal level meter:
http://www.summitsource.com/digiair-pro-tv-antenna-signal-meter-alignment-with-digital-readout-measure-the-strength-of-up-to-6-channels-at-one-time-audio-squawker-rechargeable-battery-part-digiairpro-p-6088.html?manufacturers_id=38
http://www.solidsignal.com/prod_display.asp?PROD=DIGIAIRPRO&xzoom=Large#xview
http://www.solidsignal.com/manuals/DIGIAIR_PRO.pdf

You select whether Euro modulation types (8 MHz channels) or USA (6 MHz).
Since it measures the spectrum response using a simple peak energy detector,
it will work with ANY modulation type, although the "calibration" may be
different due to average vs peak measurements, etc.