What I haven't found is off-the-shelf HPF-174 and HPF-470 filters
similar to the LPF-216 and LPF-700. We seem to be stuck choosing
between using HLSJ and UVSJ diplexors as high-pass filters, or
paying for a custom filter.That's sort of my point. Why hasn't someone come up with a LPF-700 type filter that starts at 470MHz instead of 5MHZ?

For VHF-High and UHF reception and clean-up, you need a HLSJ to block frequencies below 174MHz on the VHF antenna, then you need a LPF-700 to eliminate frequencies above 700MHz on the UHF antenna, and then these need to be fed into the UVSJ to block frequencies above 216MHz on the VHF line and block frequencies below 470MHz on the UHF line.

It would be nice to see a single product that does this, with a low insertion loss and also available in 300 ohm.

As for the DA's and pre-amps, with a narrower bandwith to amplify, I would think LNA's could become more efficient and powerful. The input filter circuits could be redesigned to offer the ability to filter out VHF-Low (much like the FM Trap) and have a cut-off at 700MHz, instead of 806MHz.

NOTE: UVSJ = 5-1000MHz and HLSJ 54-108MHz/175-216MHZ

It isn't clear to me what should be different on pre-amps and amps?

Basically nothing, their bandwidth is fine. What pre-amps would benefit most from is using newer, lower noise chips. It seems most manufacturers are stuck with chips from the last millenium, heh.

>> What I haven't found is off-the-shelf HPF-174 and HPF-470 filters
>> similar to the LPF-216 and LPF-700. We seem to be stuck choosing
>> between using HLSJ and UVSJ diplexors as high-pass filters, or
>> paying for a custom filter.

> That's sort of my point. Why hasn't someone come up with a LPF-700
> type filter that starts at 470MHz instead of 5MHZ?

They have. What I should have written is that I haven't found
anyone who sells them in the US. Soontai makes BPF-174-216,
HPF-174, HPF-470, etc. http://www.soontai.com Also
http://www.specialelektronik.se www.tratec.net

Last time I communicated with Soontai, they had a minimum order quantity of 500 units of one value. You'd have to find a domestic distributer who might have had a batch of values useful to the United States consumer broadcast spectrum.

Making your own VHF bandpass filter using an HLSJ and a UVSJ works just fine and only costs a few dollars. The "V" side of the UVSJ rolls off at about 240 MHz to a rejection depth of over 30dB.

You can buy 700 MHz lowpass filters from Channel Plus, probably for around $40. You can buy the from Soontai for a couple of bucks each if you order 500. I have previously contacted other companies in the master antenna headend business to see if I could get them to commit to take quantities of custom made filters from me if I bought 500 of one value cylindrical filter, or made the minumum purchase of 1000 UHF-BPF tunable bandppass filters, but I never could get anyone to commit beyond a couple dozen units.

There aren't going to be many filtering products made for consumers, as the age of the hobbiest ended decades ago. Go into a Radio Shack and try to find parts to build anything with. They aren't there.

Do a search for LPF-700 and you'll find them for under $25.

Maybe we can get http://www.SolidSignal.com, http://www.SummitSource.com, or http://www.Sadoun.com to carry them.

Thanks to some help from Marc Dodge here are frequency sweeps from a channel 39 Jointenna. The filters are quite wide. If you look at the 10 dB points the notch is about 5 channels wide and the bandpass is about 12 channels wide.
John

If you look at the 10 dB points the notch is about 5 channels wide and the bandpass is about 12 channels wide.


It's interesting that the notch is asymmetrical. The third channel higher should be fine but you must to go four channels down to get out of the notch. IE, channels 36-41 would be compromised.

FYI: Ken Nist updated the HDTVPrimer Antenna Comparison webpage:
http://www.hdtvprimer.com/antennas/comparing.html
including recent updates to the new antenna webpage:
http://www.hdtvprimer.com/ANTENNAS/TemporaryPage.html

Antennas Direct website now lists the C5 Hi-VHF Loop Antenna--availability late June:
http://www.antennasdirect.com/C5-Clearstream-DTV-antenna.html
including Spec Sheet/Assy Inst:
http://www.antennasdirect.com/pdf/C5-assembly-instructions.pdf

General consensus is that the Channel Master CM7000 is the best CECB. Although I've not had one to try, my best luck has been with the APEX DT502 (has S-Video & Reminder function - No channel add) and Sunkey SK801ATSC (no recall function).

There is a thread here (http://www.avsforum.com/avs-vb/showthread.php?t=546066) that deals with antennas, rotors, & pre-amps/DA's.
I have a CM7000 as well as the RS Zenith and one other (cant recall the third one)...The RS current model (Zenith) is just as good as the CM7000 except for aspect display...when showing a SD only (408i) channel on the screen in normal 4x3, the picture does NOT fill the screen...On a HD (720 or 1080) channel, it does not allow you to change the aspect and fills the screen in widescreen (16x9) unless the show is SD then it goes 4x3 and STILL fills the screen but on a SD only channel, it shows it in a weird way. I use ZOOM on the SD channels but sometimes it cuts out parts of the screen I dont want to miss...but if I go "normal" you get a black border all the way the picture..which I dont like either...the CM7000 does not do that...both as sensitive and I cannot see one above the other in that area...I like the easier rmt control of the Zenith...just dont lose it or having stolen like what happened at my office...someone walked off with the remote...luckily I have one at home so I was able to reprogram the box at work...but after 6/12 I will need to rescan or manually add in some VHF flash cuts....oh well....

systems2000 writes:
> I don't understand why manufacturers are taking so long to
> designed and produced digital OTA equipment for the
> Post-Transition configurations (ie. Pre-amps, Amps, Antennas,
> Filters, etc.). Specifically for VHF-Hi and UHF - limited
> to channel 51 at the high end.

Remember, LP analogs on 52-69 DONOT have to vacate immediately...60-69 may go quickly but 52-60 are somewhat slower to go..they dont have to vacate until the new spectrum owners ask them to....and are ready to take over the channel(s) in question. I have 3 such LP Analogs in my area all in the 6x range that will be staying on after 6/12...true they WILL go away eventually but not right now!

Tin Lee of Canada makes AC7 Single Channel Injector and higher performance AC7-CE:
http://www.tinlee.com/MATV_headend.php?active=3#ANTENNASIGNALINJECTORS
http://www.tinlee.com/CATV-Signal-Injector.php?active=1
Call/email to obtain detailed specs & price$$$...

The AC7-E series are a little better than Channel Master Jointennas. Their single channel passband can only be tuned up to UHF channel 43. They lose about 3.5 dB on the single channel and 2.5 dB on the passband. They obliterate the adjacent channel, but then slope through the alternate lower and upper channels. If your +2 and -2 channels are robust, they will withstand that degradation. Based on my familiarity with Tin Lee's pricing on comparable products, I bet these cost the better part of $200 each.

The AC7-CE is used to delete a single cable TV channel (city council, school system) and insert a locally generated channel. At VHF highband frequencies, you can see slight degradation on the lower adjacent NTSC channel. They can only be tuned up to UHF channel 27, and they probably cost around a thousand dollars each.

That's sort of my point. Why hasn't someone come up with a LPF-700 type filter that starts at 470MHz instead of 5MHZ?

For VHF-High and UHF reception and clean-up, you need a HLSJ to block frequencies below 174MHz on the VHF antenna, then you need a LPF-700 to eliminate frequencies above 700MHz on the UHF antenna, and then these need to be fed into the UVSJ to block frequencies above 216MHz on the VHF line and block frequencies below 470MHz on the UHF line.

It would be nice to see a single product that does this, with a low insertion loss and also available in 300 ohm.

As for the DA's and pre-amps, with a narrower bandwith to amplify, I would think LNA's could become more efficient and powerful. The input filter circuits could be redesigned to offer the ability to filter out VHF-Low (much like the FM Trap) and have a cut-off at 700MHz, instead of 806MHz.

NOTE: UVSJ = 5-1000MHz and HLSJ 54-108MHz/175-216MHZ

While we are lamenting non-existent products...I would love to see a device that not only took care of the above filtering, but also allowed you to plug in multiple antennae, combine then using only the strongest signals from each input and send it to the TV as one coherent signal.

No more rotators needed. Just plug in 4 to 6 antennae and make watching TV simpler, or at least more geeky.

http://www.tvfool.com/?option=com_wrapper&Itemid=29&q=id%3d249df9ae5658b0

http://www.antennasdirect.com/C4-Clearstream-DTV-antenna.html

Channel Master 7777

Ok...

You have my location (TVfool) my antenna (C4) and my Pre-amp (7777).

I get all my Digitial stations from Los Angeles fine currently. I guess my main concern is when they switch from UHF to VHF for channel 7, 9, 11 and 13. Will my setup be good for this?

I live in an apartment (with a balcony facing the correct direction for the towers). I thought this antenna would be good for High VHF but I have been reading that it might not be. I am getting really good signals on my UHF digital stations (much better then with my Squareshooter 1000).

I am about 60 miles away from the towers in the Valley.

Thanks.

While we are lamenting non-existent products...I would love to see a device that not only took care of the above filtering, but also allowed you to plug in multiple antennae, combine then using only the strongest signals from each input and send it to the TV as one coherent signal.

No more rotators needed. Just plug in 4 to 6 antennae and make watching TV simpler, or at least more geeky.


PFA-6600. I pay $550 each for them. If you can find someone to retail you one, you will probably pay a couple hundred more.

They have three UHF inputs with electronically programmable bandpass filters adjustable from one channel width to seven, a VHF high input, a VHF low, ans a VHF broadband. They also have programmable automatic gain control

You have my location (TVfool) my antenna (C4) and my Pre-amp (7777).

I'd be surprised if the C4 did well on channels 7 and 9. If not, try adding an Antennacraft Y5-7-13.

I'd be surprised if the C4 did well on channels 7 and 9. If not, try adding an Antennacraft Y5-7-13.


I don't think I can put that on my balcony. Not that my balcony is small, but I think the biggest allowed per the FCC without me getting in trouble with the managers would be 39".

I don't think I can put that on my balcony. Not that my balcony is small, but I think the biggest allowed per the FCC without me getting in trouble with the managers would be 39".

No, you misunderstand the FCC rule.

There is no size limit for an over-the-air antenna in the rule.

As long as the antenna is on an area that is for your exclusive use or control and does not extend beyond that boundary, it is probably in compliance with the FCC rule.

Note that I said "probably". Thare are a few exeptions such as historical districts, etc.

I don't think I can put that on my balcony. Not that my balcony is small, but I think the biggest allowed per the FCC without me getting in trouble with the managers would be 39".

They have a new VHF model C5 that would fit your size restriction.

http://www.antennasdirect.com/clearstream-antennas.html

They have a new VHF model C5 that would fit your size restriction.

http://www.antennasdirect.com/clearstream-antennas.html

Yeah. I saw that one coming next month. I would have to have two antennas but it is a thought. I know I can run the C5 into my VHF input and the C4 into my UHF input of my 7777.

No, you misunderstand the FCC rule.

There is no size limit for an over-the-air antenna in the rule.

As long as the antenna is on an area that is for your exclusive use or control and does not extend beyond that boundary, it is probably in compliance with the FCC rule.

Note that I said "probably". Thare are a few exeptions such as historical districts, etc.

I see this from the FCC site:

Q: What types of antennas are covered by the rule?

A: The rule applies to the following types of antennas:

(1) A "dish" antenna that is one meter (39.37") or less in diameter (or any size dish if located in Alaska) and is designed to receive direct broadcast satellite service, including direct-to-home satellite service, or to receive or transmit fixed wireless signals via satellite.

(2) An antenna that is one meter or less in diameter or diagonal measurement and is designed to receive video programming services via broadband radio service (wireless cable) or to receive or transmit fixed wireless signals other than via satellite.

(3) An antenna that is designed to receive local television broadcast signals. Masts higher than 12 feet above the roofline may be subject to local permitting requirements.

http://www.fcc.gov/mb/facts/otard.html


This is where I came up with the 1 meter size antenna.

(1) A "dish" antenna that is one meter (39.37") or less in diameter (or any size dish if located in Alaska) and is designed to receive direct broadcast satellite service, including direct-to-home satellite service, or to receive or transmit fixed wireless signals via satellite.

Notice the emphasis I added...

That section only pertains to that type of antenna.


If you read item (3) that pertains to OTA, you will see it contains no such restriction.

I don't think I can put that on my balcony. Not that my balcony is small, but I think the biggest allowed per the FCC without me getting in trouble with the managers would be 39".

You could get a Y5-7-13 and cut off the last two elements. You'd make yourself a Y3-7-13 that would be about 32" long.

PFA-6600. I apay $550 each for them. If you can find someone to retail you one, you will probably pay a couple hundred more.

They have three UHF inputs with electronically programmable bandpass filters adjustable from one channel width to seven, a VHF high input, a VHF low, ans a VHF broadband. They also have programmable automatic gain control
Available from solidsigna (http://www.solidsignal.com/prod_display.asp?PROD=PFA-6600)l, for a mere $750 or so, shipped. :D

Nice Blonder UHF Ch. 14-19 yagi for $39 on the bay.

Here is a classic Archer combo (http://cgi.ebay.com/Radio-Shack-Long-Range-Antenna-Super-Color-Special_W0QQitemZ260417099587QQcmdZViewItemQQptZLH_DefaultDo main_0?hash=item3ca2119743&_trksid=p3286.c0.m14&_trkparms=66%3A2%7C65%3A1%7C39%3A1%7C240%3A1318%7C301%3A1%7C 293%3A2%7C294%3A50), but he's pretty proud of it.

I don't think I can put that on my balcony. Not that my balcony is small, but I think the biggest allowed per the FCC without me getting in trouble with the managers would be 39".
RCA ANT751 is a new, medium range ("40-mile") antenna designed for Hi-VHF plus UHF.
I took a photo at CES2009 (Jan2009). Click image twice to see full rez version:
http://imageevent.com/holl_ands/ces2009?p=14&n=1&m=-1&c=3&l=0&w=1&s=0&z=4

And is readily available:
http://www.walmart.com/catalog/product.do?product_id=10828410
http://www.amazon.com/RCA-ANT751-Outdoor-Optimized-Reception/dp/B0024R4B5C
Walmart will ship to your local store. Shipping charges may or may not explain big cost difference.

Amazon's dimensions appear to be for the shipping box...not the antenna.
However, using 36-inches for the length of the shipping box, from the following
we see that the boom exactly fits that length...and width is about the same...or less:
http://www.tigerdirect.com/applications/searchtools/item-details.asp?EdpNo=4545184&csid=_25

RCA ANT751 is a new, medium range ("40-mile") antenna designed for Hi-VHF plus UHF.
Holy cow, thats a clipped down version of this 30+ year old thing I have ! Same phasing line style and those bent bars under the uhf driven element too.

http://img440.imageshack.us/img440/2092/dscn0273648x486486x364wk1.jpg

Ill take a photo of it from the same angle you have this afternoon, heh.

The RCA ANT751 appears very similar to the EZ HD antenna and close to the Winegard 7000R. Only the Winegard reports gain (5 to 6 dBd for UHF). I have used the EZ HD and it performed reasonably well for a small antenna. My mclapp 10x9.5 4-bay does significantly better though... :) Margin to dropout increased by 6 to 10 dB with the mclapp 4-bay.

Tigerdirect has lots of large pictures of the RCA ANT751, close ups and different angles.

http://www.tigerdirect.com/applications/searchtools/item-details.asp?EdpNo=4545184&csid=_25

Amazing, according to tiger direct:

"The RCA ANT751 offers Film Mode option that when turned on, the intelligent signal processing of the TruScan Digital Reality feature recognizes incoming video signals and progressively converts them to achieve optimum digital picture performance. The RCA ANT751 also recognizes when original film sources have been modified and can automatically convert the analog frame rate back to its original format to bring out the detail—a process commonly referred to as reverse 3:2 pulldown."

How does it do that? It's a small passive antenna!

And here it is, from a similar angle. The long vhf element is 104.75 inches tip to tip. The short vhf element is 52.125 inches tip to tip. The uhf folded dipole is 12.75 inches tip to tip.

http://img43.imageshack.us/img43/307/dscn0831v.jpg

The plastic pieces on the back arent original to the antenna. I added those for extra strength and to hold the correct spacing.

Last summer I cleaned it and had it on the roof for a fair test. From 62 miles away, vhf performance was surprisingly good. Uhf was pretty poor. More directors would probably help that.

rbarbier: per the fcc rule you can put up any antenna size you want for local broadcast reception subject only to height restrictions, "historical area" restrictions and your own personal boundaries.

if you want a 10ft beam length that's no problem.

jtm

Yep. There is a youtube video of some ham who put up a monster antenna in a high scale neighborhood. The little old ladies were up in arms, but there wasnt a darn thing they could do about it, heh.

Yep. There is a youtube video of some ham who put up a monster antenna in a high scale neighborhood. The little old ladies were up in arms, but there wasnt a darn thing they could do about it, heh.

All he had to do was use it for his TV... OTARD doesn't cover the ham antennas.

And here it is, from a similar angle. The long vhf element is 104.75 inches tip to tip. The short vhf element is 52.125 inches tip to tip. The uhf folded dipole is 12.75 inches tip to tip.

http://img43.imageshack.us/img43/307/dscn0831v.jpg

The plastic pieces on the back arent original to the antenna. I added those for extra strength and to hold the correct spacing.

Last summer I cleaned it and had it on the roof for a fair test. From 62 miles away, vhf performance was surprisingly good. Uhf was pretty poor. More directors would probably help that.
Take a very careful look at the RCA ANT751 antenna I photographed at CES2009 and are just now coming to market.
It has 4 (vice 3) VHF elements....plus 4 (vice 2) UHF elements. It also is at least one third the width and at least half the length.

What you are describing covers the Lo-VHF band, whereas ANT751 is Hi-VHF and up. And I've actually SEEN how compact it is.

All he had to do was use it for his TV... OTARD doesn't cover the ham antennas.
Yeah, but hams have been covered by other similar rules for even longer, heh. So if the landlord/homeowners association doesnt like the OTARD rules, you could tell em that youre studying for your FCC license and really put a fear into them, heh heh.

What you are describing covers the Lo-VHF band, whereas ANT751 is Hi-VHF and up.
I know, but the build and phasing lines structures are so similar, its almost scary. :eek:

So what kind of antenna would I need for the place I'll be moving into soon? It's in a bit of a low lying area with a hill to the south and raising the antenna up to 50 feet or keeping it at 5 feet doesn't seem to change the results at all.. so a large antenna say mounted on a mast 10 feet above the ground, anchored into the ground with cement work?

Just looking to get the local channels in the 170 degree area on the map.

http://www.tvfool.com/?option=com_wrapper&Itemid=29&q=id%3d249d5b60aa3b3f

CM 3018 (http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&ssPageName=STRK:MEWAX:IT&item=170338383319) on the cheap. Poorly worded listing.

Should work well for you.

Yeah, but hams have been covered by other similar rules for even longer, heh. So if the landlord/homeowners association doesnt like the OTARD rules, you could tell em that youre studying for your FCC license and really put a fear into them, heh heh.
Unfortunately PRB-1 (which I assume is what you may be thinking of) doesn't preempt CC&R (covenants, conditions and restrictions - a binding contract) :mad: So odds are, if there's a homeowners association, there's CC&R's, and these days most CC&R prohibit ham antennas. The only way this is going to change is if the Feds pass a bill to override these damn things. But at the moment most home owners associations could care less that you're a HAM (or studying to be one).

Just looking to get the local channels in the 170 degree area on the map.

A Winegard HD7694P or Antennacraft HBU-22 will work if you are willing to accept occasional fades on KCSD (PBS). A 7777 preamp is right for you.

To insure best reception of PBS you have options.

Get a larger antenna in the same series.
Aim a second antenna at KSMN and combine it with either a backwards splitter or a channel 15 Jointenna. If you use the Jointenna I'd suggest a 4 bay UHF only. To try the backwards splitter, a more directive 8 bay UHF is less likely to interfere with reception of the other stations.

The preamp is also necessary in order to split the signal to multiple TVs.

KCSD (PBS).
To insure best reception of PBS you have options.

In a 2 edge situation like yours, you may do better on PBS trying for KESD-DT on channel 8.

Yeah, but hams have been covered by other similar rules for even longer, heh. So if the landlord/homeowners association doesnt like the OTARD rules, you could tell em that youre studying for your FCC license and really put a fear into them, heh heh.



NO!!!!!!!!! YOU ARE WRONG!!! Hams have NO such rules permitting them to put up ANY size antenna, etc....even the OTARD rules limit you on what you CAN put up and that only covers TV reception; HAM antennas are EXCLUDED from that law..and it states so!!!....it must be REASONABLE....it cannot be AS BIG AS YOU WANT it....YES the little old ladies can go to their city council (if this involved a house in a NON HOA subdivision) or to the HOA if it is, and complain....READ THE RULES DUMMY!!!! YOU CANNOT put up ANYTHING...FCC PRB-1 was ONLY against CITY's and other GOVERNMENT entities PROHIBITING ham antennas...but you ARE STILL BOUND BY CERTAIN RULES (GEESH some folks DONT GET IT!!!!) YOU JUST CANT SAY FEDERAL LAW PROTECTS ME and thats that!!! THEY KNOW THE LAW (Their LAWYERS damn sure will) and you WILL get sued if you have that kind of attitude.....READ ANDN LEARN AND FOLLOW THE RULES......Otherwise, you may be paying a fine or other such "service" and your antennas WILL be down....

HAMS covered by similar rules?? NOPE SORRY, not against HOAs!!!!!! YOU ARE 100% wrong there.....I HATE it when people spew total LIES instead of the FACTS......Google PRB-1 and OTARD and read the REAL RULES....and readjust YOUR thinking......

DAMN!:eek:

Yep. There is a youtube video of some ham who put up a monster antenna in a high scale neighborhood. The little old ladies were up in arms, but there wasnt a darn thing they could do about it, heh.

IF he didnt have the proper building permit AND if the HOA didnt approve it, HE IS IN TROUBLE....The LITTLE OLD LADIES CAN DO SOMETHING ABOUT IT!!! Get your head out of the hole in the ground and READ the rules....you're the type who WOULD ruin it for everyone else with that attitude.....

A Winegard HD7694P or Antennacraft HBU-22 will work if you are willing to accept occasional fades on KCSD (PBS). A 7777 preamp is right for you.

To insure best reception of PBS you have options.

Get a larger antenna in the same series.
Aim a second antenna at KSMN and combine it with either a backwards splitter or a channel 15 Jointenna. If you use the Jointenna I'd suggest a 4 bay UHF only. To try the backwards splitter, a more directive 8 bay UHF is less likely to interfere with reception of the other stations.

The preamp is also necessary in order to split the signal to multiple TVs.

Agreed, I would go after the Sioux Falls stations unless original poster wants the MN channel which only KSMN-DT would have in that area.

HAMS covered by similar rules?? NOPE SORRY, not against HOAs!!!!!! YOU ARE 100% wrong there.....I HATE it when people spew total LIES instead of the FACTS......Google PRB-1 and OTARD and read the REAL RULES....and readjust YOUR thinking..
Oops, sorry. Im not a ham and only peruse their magazines from time to time. After seeing the TV news story I thought the FCC had passed this rule that I recalled from long ago, I guess they didnt. http://wireless.fcc.gov/services/index.htm?job=prb-1&id=amateur&page=2
The LITTLE OLD LADIES CAN DO SOMETHING ABOUT IT!!!
I guess there will be a follow up story, eventually.

Oops, sorry. Im not a ham and only peruse their magazines from time to time.

I knew that, if you were you would be calling yourself 50ohm.

I knew that, if you were you would be calling yourself 50ohm.


300ohm is his legal name. His nickname is "twinlead".

Quotes from portions of post by Dr Touchstone:
even the OTARD rules limit you on what you CAN put up and that only covers TV reception
You need to read OTARD. OTARD covers satellite dishes, video/internet services, and OTA TV.
it must be REASONABLE
I'm not sure what you are referring to but reasonable is not a term used in OTARD to describe OTA TV antennas. Once again, you need to read OTARD.
YOU JUST CANT SAY FEDERAL LAW PROTECTS ME and thats that!!! THEY KNOW THE LAW (Their LAWYERS damn sure will) and you WILL get sued if you have that kind of attitude.....READ ANDN LEARN AND FOLLOW THE RULES......Otherwise, you may be paying a fine or other such "service" and your antennas WILL be down....

Really? You can rely on Federal law, provided, in this case, you are in compliance with OTARD. And "their" lawyers know the law? Don't bet on it. There are many HOA's, including mine and cites I've seen from other posters, that try to illegally prohibit antennas allowed by OTARD. These HOA's do this either to try to intimidate homeowners from installing "unsightly" antennas or because they don't know the law.

This was not in your post but has been posted many times on these threads regarding OTARD having a 12' height limitation for antennas. There are no restrictions on the height of an antenna installation. The only restriction regarding height contained in OTARD is that if the mast is over 12 feet, its installation is subject to local zoning reguirements. That usually means installing guy wires and the like.

Your post was loud. It contained very large font, bold font, underlines, and statements in all caps. You do not need to yell at us. But, more importantly, IMO, you need to get your information correct before posting it as "fact".

PFA-6600. I pay $550 each for them. If you can find someone to retail you one, you will probably pay a couple hundred more.

They have three UHF inputs with electronically programmable bandpass filters adjustable from one channel width to seven, a VHF high input, a VHF low, ans a VHF broadband. They also have programmable automatic gain control

It is so pretty! Maybe when the price comes down closer to $200...

RCA ANT751 Bottom View Photo I also took at CES2009:
http://photos.imageevent.com/holl_ands/ces2009//P1040183.JPG
Click on image to see higher rez...
Here's an easy link to the side view I posted earlier:
http://photos.imageevent.com/holl_ands/ces2009//P1040182%20RCA%20ANT751.JPG

Look at the Driven Element (the one with thumbnuts for antenna connection).
I'm still puzzling out what the two short stubs might do...the ones that seem to go
part way forward and backwards, but not quite making contact to adjacent elements....

300ohm is his legal name. His nickname is "twinlead".
I thought it was "ladder-line"....much lower "loss when wet"...

Look at the Driven Element (the one with thumbnuts for antenna connection).
I'm still puzzling out what the two short stubs might do...the ones that seem to go
part way forward and backwards, but not quite making contact to adjacent elements....
If the links in post #9418 for holl_ands photos are broken, I have posted close-ups of the stubs later in this thread:
http://www.avsforum.com/avs-vb/showpost.php?p=16584350&postcount=9426

His link in post #9394 still seems to work (clicking on that image brings up the original 3072 x 2304):
http://imageevent.com/holl_ands/ces2009?p=14&n=1&m=-1&c=3&l=0&w=1&s=0&z=4 103K, 1024 x 768, options at bottom
Clicking on "Prev" at the upper left corner takes you to Photo 14 that is the bottom view


They appear to be UHF isolation stubs, that are usually 1/4 wave at the blocking frequency; both sections of the antenna will pick up UHF---one source must be eliminated before the UHF and VHF sections are combined into one downlead.

Reference:
TV Antennas and Signal Distribution Systems by M. J. Salvati
section on Isolation Networks pp 86-87
Howard W. Sams 1979 #21584
ISBN 0-672-21584-5

http://i496.photobucket.com/albums/rr328/rabbit73_photos/img013_1.jpg

Look for a used copy. Anyone who is interested in TV antennas should have one. It's worth the hunt.

More references:
http://www.avsforum.com/avs-vb/showpost.php?p=13734770&postcount=7164

RCA ANT751 Bottom View Photo Look at the Driven Element (the one with thumbnuts for antenna connection).
I'm still puzzling out what the two short stubs might do...the ones that seem to go
part way forward and backwards, but not quite making contact to adjacent elements....

They keep the signal from the UHF part of the antenna from being sent to the VHF part of the anternna, possibly by looking like a short at UHF frequencies.
John

...possibly by looking like a short at UHF frequencies.
correct----the outer unconnected end of the stubs is at a high impedance point; the inner connected end acts like a short.
They keep the signal from the UHF part of the antenna from being sent to the VHF part of the anternna...
Not exactly----The stubs keep the UHF signals that are picked up by the VHF section from interfering with the UHF signals picked up by the UHF section. The VHF signals picked up by the UHF section aren't as much of a problem.

I quote from the Salvati book previously mentioned:
The normal procedure in designing an all-channel antenna is to apply the vhf section to the uhf section in some manner, and connect the transmission line to the output terminals of the uhf section (which now carries both uhf and vhf signals). However, the vhf section of the antenna will pick up uhf signals also, nearly always from undesired directions. These undesired uhf signals effectively destroy the directionality of the uhf antenna, and make radical changes in its gain characteristics because of phase differences between the signal of the uhf antenna and the uhf signal of the vhf antenna......

For proper performance, therefore, the output of the vhf section must be applied to the uhf section in some manner that eliminates the uhf component......

This means that an external blocking network must be used to "choke off" the undesired uhf signals from the vhf section. The most popular (and probably most effective) technique is the one-quarter wavelength stub. These stubs are connected across the line connecting the vhf section to the uhf section. They short-circuit the lines to signals at frequencies where the stubs are one-quarter wavelength long. By making these stubs one-quarter wavelength long at uhf frequencies, uhf signals at that point on the line are shorted, while the vhf signals are not. This technique is used in Channel Master's Ultra-Hi Crossfire series. RCA antennas use two stubs of different length (illustration shows 1/4 wave stubs for 550 and 700 MHz) for increased bandwidth, as does Winegard, Antenna Corp. of America, and Jerrold Electronics.

To think of it another way:
The stubs on the antenna are like an open-end 1/4-wave coax stub used as a trap on a distribution system.

A company by the name of Johannson sells a 2-input programmable filter-amplifier. All I can find is UK pricing at 144 pounds.

This technique is used in Channel Master's Ultra-Hi Crossfire series. RCA antennas use two stubs of different length (illustration shows 1/4 wave stubs for 550 and 700 MHz) for increased bandwidth, as does Winegard, Antenna Corp. of America, and Jerrold Electronics.

Does the illustration look like this ?

http://img37.imageshack.us/img37/3280/dscn0835q.jpg

The stubs are both 6.5 inches long across, but if you count the bends 7.0 inches of metal long, which would make 1/4 wavelength just below 470 mhz.

Also note that the iron rivets seem to have protected the golden anodized finish. I noticed that on my CM1221 too.

A company by the name of Johannson sells a 2-input programmable filter-amplifier. All I can find is UK pricing at 144 pounds.


Johannson makes the PFA-6600 for PDI that I referenced. Can you provide a link to a site with the two input model?

Does the illustration look like this ?
Unfortunately, the illustration is just a line drawing that shows the concept. The two different length stubs in the drawing are facing in the same direction rather than in opposite directions as in holl_ands photos and your photo. That way, RCA could make a long and a short stub from one piece of metal and one common connection point for both.

http://i496.photobucket.com/albums/rr328/rabbit73_photos/stubs-300ohmsanttext.jpg

The location of the stubs on the transmission line between the VHF and UHF sections is important so that it traps the UHF signals coming from the VHF section without harming the UHF signals coming from the UHF section.

I would post the two pages of the book but I am concerned about copyright. I suppose I could add a disclaimer the way my library does on a copy about being for non-commercial purposes. McGraw-Hill is very fussy about copyright which keeps me from posting their diagram of the Chireix-Mesny array that is the basis for the Hoverman. It's four bi-squares stacked side-by-side for vertical polarization.

On my dial-up connection holl_ands photos take 10 and 5 minutes to download 2.8 and 1.5 Meg files (I'm not complaining, the detail in the large files helps to see the stubs), so I have extracted the stub areas (hope holl_ands doesn't mind):

http://i496.photobucket.com/albums/rr328/rabbit73_photos/RCAANT751-A-stubs_1.jpg

http://i496.photobucket.com/albums/rr328/rabbit73_photos/RCAANT751-B-stubs_1.jpg

By now, you should have an understanding of why separate UHF and VHF antennas and a UVSJ are often a better choice.

On my dial-up connection
I know what you mean, having only recently converted to fios (but Ill never go to their pay TV, heh) from dialup. I still try to keep my images to less than 150K.

Uploading the ORIGINAL image WITHOUT RESIZING, *.doc, *.rtf, *.xls (et.al.) and $25/yr
(Premium Package) for 1500 HUGE files were primary reasons I chose www.imageevent.com
Also easy to link to files. My only real gripe is it doesn't let me upload *.txt files....WTH!!!
[Which explains why I upload either *.rft or *.doc files and let the user convert to *.nec]

For the ANT751 bottom view, after you click on the (XLarge, 337x253, 26.3 KB) thumbnail,
the default view is 1024x768 (125 KB). Next click opens Original 3072x2304 (Huge: 2757 KB).
Which is barely a blink of an eye via my 12 Mbps cable modem.

I just added an 800x600 (81.1 KB) option (see below the default image).
There is an even smaller option, but another small reduction probably isn't worth it.
Let me know if it helps....and if not I'll delete the 800x600 option.
I would guess going to a smaller image size isn't going to help...

I changed the file compression setting for uploaded files for Max PQ. Above file sizes
reflect this change (grew by about 33%). Let me know if 1024x768 is "adequate".
[I reloaded the two ANT751 files...and will be in effect for all future files uploaded.]

But I'm not going to resize every ORIGINAL I post---which was a BIG reason
for going with imageevent....I could simply upload groups of ORIGINAL images as-is
(or after I crop and adjust brightness/contrast). [Unlike most popular websites...]

FYI: Imageevent doesn't need ZOOM control--simply use CTRL+ and CTRL- in web browser.

PS: Do you see controls to vary thumbnail sizes and number of images/column???
And perhaps the default image size??? [It's difficult for me to see what a user sees.]

PPS: Can you tell I'm killing time waiting for IDRick to respond to measurement Q's...

holl_ands:

I didn't mind the large file size because I knew that it would give me good detail in the stub area.
("Good things are worth waiting for.")
But I'm not going to resize every ORIGINAL I post---
That's fine with me.
PS: Do you see controls to vary thumbnail sizes and number of images/column???
And perhaps the default image size??? [It's difficult for me to see what a user sees.]
No, only the hi res file.

Thanks for the imageevent info.

For your first photo Ctrl+ and Ctrl- works well with my IE7 browser. Clicking on the image changes the pixel size, but not the file size. I don't see any way to change the file size expect the way I did it for the stub areas that I posted using crop for the photo and using my ZoomBrowser software that came with my Canon digital camera to produce a web suitable image.
For the ANT751 bottom view, after you click on the (XLarge, 337x253, 26.3 KB) thumbnail,
the default view is 1024x768 (125 KB). Next click opens Original 3072x2304 (Huge: 2757 KB).
Which is barely a blink of an eye via my 12 Mbps cable modem.

I just added an 800x600 (81.1 KB) option (see below the default image).
There is an even smaller option, but another small reduction probably isn't worth it.
Let me know if it helps....and if not I'll delete the 800x600 option.
I would guess going to a smaller image size isn't going to help...
I didn't see those choices when I downloaded your image from post #9418; only the high res large file came up.

I did, however see the choices you describe when I clicked on the first link in post #9394.

Wouldn't I need to logon at imageevent and be able to see your album before I would see those choices? Or, wouldn't you instead need to post the link to your album page that gives those choices?

Update sat june 6: both links in post #9418 are broken.

Best regards,
rabbit

using my ZoomBrowser software that came with my Canon digital camera to produce a web suitable image.
Pixresizer is another good, extremely simple freeware program to use.

Hi speed internet is nice, especially for watching something like hulu TV.

Well I just picked up a 15-1634 (http://www.avsforum.com/avs-vb/showthread.php?p=14047874#post14047874) from Radio Shack. Replaced a CM 3010. Overall, it's "ok". There is a good deal of bouncing on the signal meter but it rarely drops below 60% except on a few channels. But it does loose the lock on 30 and 69 which is unacceptable.

This looks like multipath interference since it bounces between 90% & 60%. I wonder if the Winegard or Channel Master omni's are any better? The Bottom line is I think we can do better and this bad boy will go back to Radio Shack when I find a replacement. We have quite a few trees around the house but are not sealed in. Alas, the antenna quest continues.

It looks like that Radio Shack omni is amplified. You cannot use anything amplified with so many powerful signals at your location. I see that Winegard makes a non amplified omni, but I don't have any experience in recommending omni's.

http://www.solidsignal.com/prod_display.asp?PROD=MS-1000

And that preamp that comes with it looks like the cheapie one RS sells. It has a very high noise factor.
It looks like you could use the unit without the the preamp at all. Give that a shot.

holl_ands wrote:
And musn't overlook the coat hanger....it's a classic...:D
Kerry Cozad measured a "4-leaf-clover" antenna pattern:
https://secure.connect.pbs.org/conferences/technology/2005/Sessions/TC05_43.htm

[Although I might try reworking the feed to improve the VSWR.....]
-------------------------------------------
Ha ha ha ha ... I needed a good laugh today! :D Oddly, it probably works to some extent!

Jim in Seattle (catching up on prior posts here, starting from page 1)

And that preamp that comes with it looks like the cheapie one RS sells. It has a very high noise factor.
It looks like you could use the unit without the the preamp at all. Give that a shot.

I was aware of the amplification issue as well with this antenna. When removing the preamp, I pretty much loose the signal completely. I too frowned at the quality of the pre-amp RS shipped with a $90 antenna. The key is that it can be returned without a mail campaign.

The setup is working though, I am getting in the 90's with everything but one station (CW) that is pegged at 69%. Reception is notably better than the CM3010. I really can't complain about the 15-1634.

I may order a non-amplified omni for sanity purposes but I am thinking this is about as good as it will get. The tricky thing with this business is knowing when to be content ;)

Although steel has much lower conductivity than copper or aluminum, people have been
making antennas out of Coat Hangers since...the invention of the Coat Hanger???

It's not just a recent U-Tube infatuation. For example the fol. 1950's VHF antenna attached.
You can see patents (after FREE Registration) at www.freepatents.com

cgulliver, also not that the RS 1634 antennas are 3 way directional, corresponding with the curves in the outer casing.....a little rotation might help.

rabbt73, thanks for the book recommendation.

For example the fol. 1950's VHF antenna attached.
Thats not bad at all, the dude put a reflector and a couple of directors on his coathanger, heh.

cgulliver, also not that the RS 1634 antennas are 3 way directional, corresponding with the curves in the outer casing.....a little rotation might help.

Thanks, I did notice improvement after some rotation. The only issue now is that CBS is somehow going from 93% to zero every so often. I am hoping a turn or two will resolve this. The 1634 antenna looks like a re branded "AntennaCraft 5MS921" right?

If it doesn't work out, whats my next best option considering I need to hit multiple directions and don't want to put in a rotator. I have the CM3010 but it was worse than this one. I really like the aesthetics on this antenna though.

"AntennaCraft 5MS921" right

I believe so.

The dropping out is probably from overload. You are going to have to find a nuanced spot to bring in the strong stations as well as the weaker stations.


You could probably use a 2 way omni directional config given your transmission directions. There is always the RS 1892 UFO....if a bit bothersome with repositioning the antenna via the remote (someone said they configured a univeral remote to operate the UFO).

I would suggest you try a Antennas Direct C1 Convertible. Channel 7 is on the edge at 45 miles with a CM7777 amplifier (flat land but I have tree problems). Its wide beamwidth and good performance unamped should/could work well for you.

The Philips MANT940 might be worth looking into, it offers some gain on VHF Hi (enough for some strong transmissions) and has a wide beamwidth and is bi directional.

Have you tried just a RE&Loop?

I need some advice about an antenna to deal with multipath.

I'm 40 mi from the two signals I want. I currently have a CM 4228 with a CM 7777 preamp and rotator. And the 4228 simply cannot clear out the multipath caused by the neighboring houses in the direction.

Previously, when I had the 4228 lower, there was a narrow sweet spot when I could tune them. Since I wen higher, it's been hell.

I'm almost 100% sure this is an issue that would best be handled with a narrow antenna like a 91XG. I want to try adding a second antenna (since the CM 7777 has the extra input for it). Since the 4228 will be aimed mostly SW at 240 degrees, and these two signals are SE at 140 degrees, I don't think it will be an issue.

Is 91XG overkill? Should I go with the 42XG? Or would anyone suggest a different antenna?

Is 91XG overkill? Should I go with the 42XG? Or would anyone suggest a different antenna?I'm not sure what you mean by overkill, but if you suspect multipath, the 91-XG is a better choice than the 4228. The 91-XG is also a 43-XG with the front section left off. I've tried the 4228, HD8800, & 91-XG in my extreme multipath area, and the 91-XG is the clear winner.

It sounds like you are planning to use both antennas with the 7777. You can only use separate UHF & VHF antennas, not 2 UHF antennas. The 4228 would still work for VHF if that is what you were intending to use it for.

"AntennaCraft 5MS921" right

Have you tried just a RE&Loop?

Thanks for the feedback. I have been tweaking the aiming on the RS 1634 and it has produced very good results. The only real issue seams to be an occasional audio dropout on 2.1 although it is pegged from 80-90% and the video doesn't appear to pixelate. 69.1 is a little weak but stays in the 65-70% range.

I have not tried an RE & Loop since my set is in the basement but suppose I could put one in the attic. There are a good deal of trees around also, so my hunch is that the amplifier may help on some of the signals.

I will probably check out a Philips MANT940 though.

It sounds like you are planning to use both antennas with the 7777. You can only use separate UHF & VHF antennas, not 2 UHF antennas. The 4228 would still work for VHF if that is what you were intending to use it for.

My 7777 has a switch that allows you to set both antennas to work as VHF/UHF, fundamentally making the preamp also a combiner. I don't know if it is the year it was made or what, but when I originally bought it and installed it at the old house (2006, I think), I was using it with two fixed VHF/UHF antennas, with one pointed SE (Altoona, PA), one pointed SW (Pittsburgh, PA). Worked fine.

When I moved to the new house (two Novembers ago) I was happy with the reception. I held off on using the second input, because none of our locals had gone VHF at the time I installed the 4228. Now that I know it does the VHF channels very well, I figure I might fix those last two stragglers with the multipath issue.

I have a question about how accurate one needs to be with regard to aiming an antenna. I live SW of Providence, RI. According to TV Fool and an accurate postion fix from Google Earth, the transmitters for the channels that I want to watch are coincidentally located in two primary compass directions. The Providence stations are mostly 038 degrees at an average of 23 miles from my home. The Boston stations are mostly located at 028 degrees at approx. 52 miles. I don't know how accurate one's aim needs to be. If I set the antenna at 033 degrees (half way in the middle), should I be able to get these two "sets" of channels? I know some trial and error is likely going to give me the answer. But, for starters, I need to know how accurate I need to be. I've been using cable for nearly 30 years. I forgot how to set up an OTA system.

If your 23 mile transmitters are at least 100KW, you shouldn't have much trouble with reception. 10° isn't much for a wide-beam width antenna. I'd concentrate on the 52 mile stations.

I'm not sure what you mean by overkill, but if you suspect multipath, the 91-XG is a better choice than the 4228. The 91-XG is also a 43-XG with the front section left off. I've tried the 4228, HD8800, & 91-XG in my extreme multipath area, and the 91-XG is the clear winner.

It sounds like you are planning to use both antennas with the 7777. You can only use separate UHF & VHF antennas, not 2 UHF antennas. The 4228 would still work for VHF if that is what you were intending to use it for.
Your info is correct except that the 43XG is a 91XG with the front section left off.:)

Thanks for the feedback. I have been tweaking the aiming on the RS 1634 and it has produced very good results. The only real issue seams to be an occasional audio dropout on 2.1 although it is pegged from 80-90% and the video doesn't appear to pixelate. 69.1 is a little weak but stays in the 65-70% range.

I have not tried an RE & Loop since my set is in the basement but suppose I could put one in the attic. There are a good deal of trees around also, so my hunch is that the amplifier may help on some of the signals.

I will probably check out a Philips MANT940 though.

You might consider the Philips MANT950 as well. Im not positive, but I think the UHF section is bi directional, the VHF section is definitely.

Also Ive been testing the AntennasDirect ClearStream1 Convertible, and its been doing very well, and I think it also would be a strong contender for you. However, maybe the reduced gain of the RS 1634 is actually beneficial for your situation with the strong signals overloading.

Note both the MANT940 and MANT950 have integrated amplifiers. The AD C1C does not.

One more thing.....if you try the MANT940, mount it in the "sideways" position with the wedge facing upwards.

One more thing.....if you try the MANT940, mount it in the "sideways" position with the wedge facing upwards.

Are we certain the MANT940 picks up VHF as well? I was in Wal Mart yesterday but did not purchase it since it states UHF only on the box.

I removed the amp from the 1634 and it was a no-go. There are trees all the way around my house so the amp may be ok. Aside from an occasional audio dropout on ABC, the 1634 is the winner so far. I am afraid that this one will suffer from intermittent issues related to multipathing though. But I havent ruled out these issues being caused by overloading.

Also, are the RCA ANT751 or the CM3016 good choices for me? I was not sure since the towers are all around me (see below). I tested out the CM 3010 last night again and it didn't work out. I don't want to put in a rotator.

http://i42.tinypic.com/o8rsqd.jpg

Hey everyone, i am a newbie to OTA and antennas. I just got my first antenna, "Antennas Direct DB2", i hooked it up and got most of the channels but not getting any VHF channels(they are scrambled). I know DB2 is a UHF antenna but can i also get VHF channels?
Can i use another VHF antenna and use both of these antennas to get both UHF and VHF signals. Please help me out

Hey everyone, i am a newbie to OTA and antennas. I just got my first antenna, "Antennas Direct DB2", i hooked it up and got most of the channels but not getting any VHF channels(they are scrambled). I know DB2 is a UHF antenna but can i also get VHF channels?
Can i use another VHF antenna and use both of these antennas to get both UHF and VHF signals. Please help me out
As you can see in the link provided below, a DB2 is useless for VHF:

http://www.hdtvprimer.com/ANTENNAS/comparing.html

I don't know what you mean by "scrambled." That's usually a term used in cable systems for signals you haven't paid for or subscribed to. Do you mean they are stuttering and pixelating? Is this digital, I assume?

You'll need something else for VHF in any event. We'd need more details about your situation (zip code, distance from the towers, TV Fool output, that kind of thing) in order to be of more help.

Walmart will let you return the antenna if it doesnt work out. The MANT940 isnt a VHF antenna, however it does offer some negative gain on VHF Hi which is good enough for some strong channels.

I think you can do better than the RCA ANT751, CM 3016 for your particular situation.

As you can see in the link provided below, a DB2 is useless for VHF:

http://www.hdtvprimer.com/ANTENNAS/comparing.html

I don't know what you mean by "scrambled." That's usually a term used in cable systems for signals you haven't paid for or subscribed to. Do you mean they are stuttering and pixelating? Is this digital, I assume?

You'll need something else for VHF in any event. We'd need more details about your situation (zip code, distance from the towers, TV Fool output, that kind of thing) in order to be of more help.

I am not getting any Digital VHF channel, the scrambling I refer to is the the fuzziness in the analog VHF channels I am getting.
I live in Sunnyvale, zip-94089 and I am located 50 miles away from the towers(towers are in San Francisco). I am getting all UHF channels pretty clear in HD. I have got HDTV with Digital Tuner and I have my antenna setup in my balcony (2nd floor of a 3 floor building).
I hope this information will help, please suggest a way to get VHF channels too

Your tvfool report for zip 94089 is at this link:

http://www.tvfool.com/?option=com_wrapper&Itemid=29&q=id%3dc53474effbc2c6

If you go to tvfool.com and enter your exact address the results will be more accurate. Give us the URL near the top of the page in bold type as I have done; your address will not show in the report. I don't think you have much analog to worry about on friday---that's when the transition to digital happens.

For VHF you will need a VHF antenna. It can be combined with your UHF antenna with a UHF/VHF combiner called a UVSJ.

You have NBC on VHF ch 12, and ABC on 7. What channels do you want?

Update: I think he went to the local reception thread for San Francisco.

please suggest a way to get VHF channels too
You could try replacing the DB2 reflector with one that is 32 to 44 inches wide. 2 X 4 mesh or smaller should be used. That works for getting some vhf-hi gain on a 4 bay bowtie and should on a 2 bay one too, with a little less gain. But some is better than none.

Hmm, because of the way the present DB2 reflector is made, a quick test would be to inter-weave two 36 inch long metal rods horizontally behind each of the bowties. Tearing up old rabbit ears would give you tunable rods, heh.

7 is still on UHF until some time tomorrow.

11 (RF 12) is the only VHF on right now.

I have a DB2 and get VHF channel 11 (dt) with no problem. The TX is about 35 to 40 miles away.

People on the walmart website said that MANT940 works for VHF high as long as the signals are fairly strong.

At this point in time I wouldn't even bother trying to get analog channels, they'll be blank tomorrow

they'll be blank tomorrow
From what I gather, different stations cut over at different times during the day. Looks like Saturday morning for a full scan, heh.

People on the walmart website said that MANT940 works for VHF high as long as the signals are fairly strong.

At this point in time I wouldn't even bother trying to get analog channels, they'll be blank tomorrow

Ok, I installed the MANT940 and could not get a lock on anything. 0% across the board. Doesn't make sense. I even confirmed everything was properly hooked up and tried several positions. Maybe the unit was DOA... shrug. I may try it on another set I have upstairs just to confirm.

Anyways, the good news is I have been tweaking the aiming of the RS 1634 and it has done wonders for my reception. I've reached a point where it is working well enough not to screw with it. All the big networks are 90%+ and I get at least 70% on everything else. I will cross my fingers and rescan this afternoon.

Thanks for all the support

I continue to be happy with my cheapy Terrestrial Digital DB2 antenna. It worked much better than any of my home-made antennae (DB1's, DB2's, DB4's, loops, a hoverman, etc). I did a re-scan of the channels this morning and gained 2 more digital stations. I am now up to 30 total. I am missing out on a few digital stations out of Dayton, but the antenna isn't pointed that way in the first place.

People on the walmart website said that MANT940 works for VHF high as long as the signals are fairly strong.

At this point in time I wouldn't even bother trying to get analog channels, they'll be blank tomorrow

If your signals are strong enough, a paper clip will get the UHF and VHF signals.

A UHF antenna will receive the VHF signals, but at a much lower efficiency level. As long as the final signal product is strong enough, the antenna "works" for the consumer regardless of whether it's the "right" one.

Dennis Wallace of MSW (Meintel, Sgrignoli, & Wallace) measured the Gain
of several passive and active (amplified) antennas, as briefly summarized here:
http://www.walb.com/Global/story.asp?S=8346127
[BTW: MSW principals were very instrumental in original ATSC development & test.]

Philips MANT940 had 17.1 dB less Active Gain on Ch7 as the Terk TV25:
http://www.solidsignal.com/prod_display.asp?PROD=TV25&xzoom=Large#xview
and 6.2 dB less Active Gain on Ch7 as Rabbit Ears on RCA ANT585:
http://www.solidsignal.com/prod_display.asp?PROD=ANT585&xzoom=Large#xview

Subtracting respective Preamp Gains reveals fol. actual ANTENNA Ch7 Gains:
- 8.1 dBd RCA ANT585 (VHF Rabbit Ears + UHF Loop)
-13.7 dBd Philips MAN940 (Small Indoor/Outdoor Blade)
-19.3 dBd W-G SS2000 (SquareShooter--Big Outdoor Panel)
+ 2.8 dBd Terk TV25 (TV Hugger Bowtie)
-12.4 dBd W-G SS3000 SharpShooter "ScatterPlane" (aka Terk HDTVLP)

Compare to Passive Antenna Ch7 Gains:
- 5.2 dBd RCA ANT115 (VHF Rabbit Ears + UHF Loop)
-25.0 dBd Philips Silver Sensor (Small Indoor Log Periodic)
-20.4 dBd W-G SS1000 (SquareShooter--big outdoor panel)
-14.1 dBd A-D DB-2 (2-Bay Bowtie w Reflector)
-18.2 dBd Terr Digital 303F (I have no clue what this is.....)

For Ch7, the clear winner was the Terk TV25, followed by the VHF Rabbit Ears....
All of the other antennas had high to extremely high loss on Ch7.....
The worst of the bunch on Ch7 was the Winegard SquareShooter....

Of course, results may be somewhat different on Ch8-13....

And remember to add 2.15 dB to convert dBd to dBi.

While everyone's interest is focused on Hi-VHF Antenna performance, here's the link to
mclapp's on-air VHF/UHF measurements comparing R-S VU-90 Combo and (old) CM-4221 4-Bay
to several of his Super-Sized 4-Bay and 8-Bay antenna designs:
http://www.frontiernet.net/~mclapp/Antennas/plots/

Below I attached Kerry Cozad's (Dielectric Antennas) model range results for Silver Sensor,
Terk HDTVi, RCA ANT3023 Combo, Rabbit Ears/Loop, CM4228 (old 8-Bay) and W-G PR-8800 (old 8-Bay).

Last year, Bob Chase (Houston Station Engineer) posted an on-air comparison of 8 antennas.
I took his spectrum analyzer signal level readings and prepared a VHF comparison chart.

Note how well the (old) CM4228 performed on Hi-VHF channels, except for dip across Ch7-8 boundary.
Unfortunately, the latest 8-Bay antennas need some modifications:
http://www.hdtvprimer.com/ANTENNAS/TemporaryPage.html
Additional NEC simulation model comparisons:
http://www.hdtvprimer.com/antennas/comparing.html
[PS: Always take NEC sim results with a grain of salt....gain notches had minimal effect wrt on-air tests.]

On-Air test comparisons from mclapp:

http://www.tvfool.com/?option=com_wrapper&Itemid=29&q=id%3d249df9ae5658b0

http://www.antennasdirect.com/C4-Clearstream-DTV-antenna.html

Channel Master 7777

Ok...

You have my location (TVfool) my antenna (C4) and my Pre-amp (7777).

I get all my Digitial stations from Los Angeles fine currently. I guess my main concern is when they switch from UHF to VHF for channel 7, 9, 11 and 13. Will my setup be good for this?

I live in an apartment (with a balcony facing the correct direction for the towers). I thought this antenna would be good for High VHF but I have been reading that it might not be. I am getting really good signals on my UHF digital stations (much better then with my Squareshooter 1000).

I am about 60 miles away from the towers in the Valley.

Thanks.

Alright, just as you guys predicted, I lost my High VHF channels (7, 9, 11, 13) with the DTV switch. I get great UHF and was getting these channels when they were UHF. Do you think that Antennasdirect C5 along with the C4 running into my 7777 will get me 7 and 11 (I really don't need 9 or 13 but if I get it that would be a fine). I get 0 signal on the High VHF channels with the C4.

Alright, just as you guys predicted, I lost my High VHF channels (7, 9, 11, 13) with the DTV switch. I get great UHF and was getting these channels when they were UHF. Do you think that Antennasdirect C5 along with the C4 running into my 7777 will get me 7 and 11 (I really don't need 9 or 13 but if I get it that would be a fine). I get 0 signal on the High VHF channels with the C4.


You're a bit far for the C4's limited H-VHF capability. That usually maxes out around 40-50 miles with good LOS and adequate signal power. Since you're missing LOS and are at around 55-60 miles, you will definitely need a dedicated H-VHF antenna.

The C5 might be enough, certainly worth a try, especially since it's very compact but of similar performance to a 5-element Yagi. A little birdie told me a small quantity may be shipped by a really big birdie in the next day or so, maybe those will be made available for purchase.

BTW, how is the C4 doing with the UHF signals coming from Mt Wilson to your location?

You're a bit far for the C4's limited H-VHF capability. That usually maxes out around 40-50 miles with good LOS and adequate signal power. Since you're missing LOS and are at around 55-60 miles, you will definitely need a dedicated H-VHF antenna.

The C5 might be enough, certainly worth a try, especially since it's very compact but of similar performance to a 5-element Yagi. A little birdie told me a small quantity may be shipped by a really big birdie in the next day or so, maybe those will be made available for purchase.

BTW, how is the C4 doing with the UHF signals coming from Mt Wilson to your location?

The C4 is doing great with the UHF. I get all the UHF channels at 80+ percent (I think my TV needs above 35 for a picture). With my Squareshooter 1000, I was around 65+. I will try the C5.

Channel Master CM 3671

Has anyone used this or know how reliable it is? Have never used Channel Master before and thinking of ordering this antenna.

We are trying to get the ones in in red located to the NW in Nashville some 70+ miles away.

http://www.tvfool.com/modeling/tmp/663d/302/7b8a44f/Radar-Digital2.png

Channel Master CM 3671

Has anyone used this or know how reliable it is? Have never used Channel Master before and thinking of ordering this antenna.The Winegard HD8200P is a better antenna, especially for UHF. If you don't need VHF-LO, the HD7698P is the equivalent channel 7-69 antenna. It is much smaller and lighter than the 8200.

Both antennas are very well constructed.

The Winegard HD8200P is a better antenna, especially for UHF. If you don't need VHF-LO, the HD7698P is the equivalent channel 7-69 antenna. It is much smaller and lighter than the 8200.

Both antennas are very well constructed.

I have the 8200 and have been very happy with its quality and performance. I however am not quite as far out as SequatchieViewer.

I'd like to offer you two suggestions you can try that may improve your reception.

1. To maintain the symmetry of your antenna, wrap electrical tape around the board every 6" or so.
2. Use screw terminals (wood screws and washers) at the feed point to maintain a 1" gap and attach a high quality balun (Channel Master 0089 (http://www.summitsource.com/channel-master-0089-outdoor-balun-matching-transformer-excellent-matching-with-lowest-trough-loss-tv-antenna-offair-300-to-75-ohm-with-weather-boot-1-pack-balun-antenna-twin-lead-balum-part-0089-p-8141.html)) there.

I finally got around to taking some pics of the updated version of my channel 7 folded dipole. Here it is:

http://img4.imageshack.us/img4/6002/foldeddipole1.th.jpg (http://img4.imageshack.us/my.php?image=foldeddipole1.jpg)
http://img15.imageshack.us/img15/3707/foldeddipole2.th.jpg (http://img15.imageshack.us/my.php?image=foldeddipole2.jpg)

With the end loops soldered I was able to make the copper taut upon tightening the screws, and I added a high quality balun that feeds RG-6 coax. Much prettier now and still works great for pulling in VHF-HI channels 7 (cut for that channel) and 9. Also works with channel 12 on a CECB, but some signal loss on signal meter.

I have two markets that are almost 180 deg apart in heading. I'd like to put two CM4221s (or CM4228s) back-to-back on the same mast. Will one antenna affect the performance of the other? I will NOT be combining the downleads; each will be separately delivered to an A-B switch. I remember there being something called a "capture area" that recommended antennas be separated vertically on the same mast, but I don't recall the details.

Can any of you real antenna experts comment?

Thanks.

While everyone's interest is focused on Hi-VHF Antenna performance, here's the link to
mclapp's on-air VHF/UHF measurements comparing R-S VU-90 Combo and (old) CM-4221 4-Bay
to several of his Super-Sized 4-Bay and 8-Bay antenna designs:
http://www.frontiernet.net/~mclapp/Antennas/plots/

Below I attached Kerry Cozad's (Dielectric Antennas) model range results for Silver Sensor,
Terk HDTVi, RCA ANT3023 Combo, Rabbit Ears/Loop, CM4228 (old 8-Bay) and W-G PR-8800 (old 8-Bay).

Last year, Bob Chase (Houston Station Engineer) posted an on-air comparison of 8 antennas.
I took his spectrum analyzer signal level readings and prepared a VHF comparison chart.

Note how well the (old) CM4228 performed on Hi-VHF channels, except for dip across Ch7-8 boundary.
Unfortunately, the latest 8-Bay antennas need some modifications:
http://www.hdtvprimer.com/ANTENNAS/TemporaryPage.html
Additional NEC simulation model comparisons:
http://www.hdtvprimer.com/antennas/comparing.html
[PS: Always take NEC sim results with a grain of salt....gain notches had minimal effect wrt on-air tests.]

I have two markets that are almost 180 deg apart in heading. I'd like to put two CM4221s back-to-back on the same mast.

Can any of you real antenna experts comment?


Many in your situation buy a 4221 and simply remove the reflector screen.

Many in your situation but a 4221 and simply remove the reflector screen.
That would result in an omnidirectional antenna, but just like before the transition, I would be left with co-channel problems. In the old case, the co-channel problems were NTSC into DTV, and in the UHF band. The analogs kept me from receiving the digitals. Now the co-channel is DTV into DTV, and this time in the VHF band. I don't want to have a problem with co-channel this time. If I have to, I'll pick one DMA and lose the other.

Unless you use an A-B switch, it is not as easy as using a splitter/combiner in your situation, most likely.

Boy there are some cool looking antennas here.

http://img.timeinc.net/time/photoessays/2009/television/television_06.jpg

I like the corner reflector with the bowtie. Ive seen one in an old Radio Shack catalogue from the 80s.

Neat, a Rhombic. And a small one at that.

Hi all. I've been reading the forums for about a year, but still, most of this is over my head.
Rabbit ears weren't getting the job done (weak signals, constant adjustment), and just picked up an Antennas Direct C2 @ Best Buy (which will be going back - $30 overpriced.)

The C2 solves the immediate issue, but is there something better, or cheaper for the job?
I'm not trying to pull in any long range signals.
I'd prefer to stay away from a Yagi, but if that's the best, let me know.

Mounting height was planned to be 16', but could go as high as 24' (multi-level house).
I know higher is better, but I've got a metal chimney and evaporative cooler on the high roof.

And I'd like to drop it to 4 locations, so a recommendation on a pre-amp or not would be great.

My TV Fool Plot - /?option=com_wrapper&Itemid=29&q=id%3d663d943b85fe8f

(1st post, so can't paste URLs yet.)

Any suggestions are appreciated, and thanks for the feedback!

Hi all. I've been reading the forums for about a year, but still, most of this is over my head.
Rabbit ears weren't getting the job done (weak signals, constant adjustment), and just picked up an Antennas Direct C2 @ Best Buy (which will be going back - $30 overpriced.)

The C2 solves the immediate issue, but is there something better, or cheaper for the job?http://www.avsforum.com/avs-vb/showthread.php?t=798265

Unless you use an A-B switch, it is not as easy as using a splitter/combiner in your situation, most likely.
I'm not planning on using a splitter or combiner. My question was about any interaction between antennas placed back-to-back on the same mast.

Ken H,
Thanks, I was actually thinking about making one, but it needs to be an outdoor antenna. All my attic space is either finished or cathedral ceilings.

I have two markets that are almost 180 deg apart in heading. I'd like to put two CM4221s (or CM4228s) back-to-back on the same mast. Will one antenna affect the performance of the other? I will NOT be combining the downleads; each will be separately delivered to an A-B switch. I remember there being something called a "capture area" that recommended antennas be separated vertically on the same mast, but I don't recall the details.
I think that it is unlikely that they will interfere with each other if the reflector screens are left on and they are back-to-back. When I aim my 4221 I am behind it with my signal level meter (SLM) and I don't notice any change from the presence of my body like happens when I'm in front of it. You could always space them vertically later so that they just clear each other if there is a problem. Keep the coax behind the reflector screens after bringing it straight back thru the screen from the feed point.

Some hams use just one reflector screen with an antenna on each side with an A-B switch to change direction 180 degrees rapidly. The closer the vertical spacing of the horizontal wires, the better the isolation and the greater the front-to-back ratio (for a horiz. polarized antenna). The rule of thumb is that the spacing should not be greater than 0.1 wavelength, which would be 1181 divided by the frequency in MHz with the answer in inches. Example for CH 15: 1181 divided by 476 = 2.3 inches. The 1181 is derived from two times the free-space halfwave length (5905) in inches divided by 10.

The capture area is taken into consideration when you are stacking two yagis one-above-the-other that are pointing in the same direction and are phased together for more gain than one yagi. For maximum gain they are spaced so that the capture area of one just touches the capture area of the other; not easy to calculate.

I am now considering a Blonder Tongue BTY-10-U(A) yagi for channel 16. How does this antenna actually compare to other UHF antennas at channel 16. Will it actually give 10dBm net gain at channel 16? Will it do better (as in...will it have better gain at 16 than at 14 and 19, to perhaps 11dBm?

I can find no rally good info on the performance of this antenna.

Any help would be appreciated. I currently use a 91XG and a large Antennacraft MXU59 for UHF (different directions) but I am looking at the BT specifically for channel 16 in another direction. Will this be as good as these antennas at this frequency, or will it be better or worse?

Bill

Hi all. I've been reading the forums for about a year, but still, most of this is over my head.
Rabbit ears weren't getting the job done (weak signals, constant adjustment), and just picked up an Antennas Direct C2 @ Best Buy (which will be going back - $30 overpriced.)

The C2 solves the immediate issue, but is there something better, or cheaper for the job?
I'm not trying to pull in any long range signals.
I'd prefer to stay away from a Yagi, but if that's the best, let me know.

Mounting height was planned to be 16', but could go as high as 24' (multi-level house).
I know higher is better, but I've got a metal chimney and evaporative cooler on the high roof.

And I'd like to drop it to 4 locations, so a recommendation on a pre-amp or not would be great.

My TV Fool Plot - /?option=com_wrapper&Itemid=29&q=id%3d663d943b85fe8f

(1st post, so can't paste URLs yet.)

Any suggestions are appreciated, and thanks for the feedback!
Welcome to the forum.

I can't get that url to work even after adding the front part. Please double check it or do a few more posts so that you will be able to post a hot link. For now maybe you could just give us the zip. (Sometimes the tvfool server is overloaded and the link can't be made.)

I thought I was ready for the analog-digital switch. I didn't realize some of the stations were going to switch from uhf to vhf. I've been watching the digital uhf just fine for years. Why would they do that? Now I need another antenna. It looks like the CM 7777 will be a good way to go for separate vhf/uhf with preamp. Any recommendations for a vhf antenna?

Thanks, rabbit.
Sorry all for the dummy post here...

Boy there are some cool looking antennas here.
I cant figure out the one directly under the helix antenna, or is it just a mast ?

Welcome to the forum.

I can't get that url to work even after adding the front part. Please double check it or do a few more posts so that you will be able to post a hot link. For now maybe you could just give us the zip. (Sometimes the tvfool server is overloaded and the link can't be made.)

Thanks, rabbit.

http://www.tvfool.com/?option=com_wrapper&Itemid=29&q=id%3d663d943b85fe8f

If you only need VHF-hi (channels 7-13) then I recommend a Winegard YA-1713.

Bill

but is there something better, or cheaper for the job?
I'm not trying to pull in any long range signals.
I'd prefer to stay away from a Yagi, but if that's the best, let me know.
If youre looking for inexpensive, the Antennacraft HBU22 for $30 will do your strong signals, uhf and vhf-hi. You may even be just fine with the Antennacraft AC9 for $18. Antennacraft makes (or did make) the Radio Shack antennas, so good or bad, that gives you an idea of the quality.

Hmm, when you say local stations, you dont mean those super weak channels 1.1 miles from you ? They must be transmitting on D cells, heh.

That would result in an omnidirectional antenna, but just like before the transition, I would be left with co-channel problems. In the old case, the co-channel problems were NTSC into DTV, and in the UHF band. The analogs kept me from receiving the digitals. Now the co-channel is DTV into DTV, and this time in the VHF band. I don't want to have a problem with co-channel this time. If I have to, I'll pick one DMA and lose the other.

My initial response was that two 4221's facing away from each other should not interfere. I believe this is true for UHF, but I'm not so sure that's true for VHF when using the 4221. The 4221 is a UHF antenna. Any VHF signal get's picked up by the reflector, rather than the bow-tie elements, so it's possible that the reflectors could interfere with each other if placed so closely. Perhaps some of the "experts" can comment.

If youre looking for inexpensive, the Antennacraft HBU22 for $30 will do your strong signals, uhf and vhf-hi. You may even be just fine with the Antennacraft AC9 for $18. Antennacraft makes (or did make) the Radio Shack antennas, so good or bad, that gives you an idea of the quality.

Hmm, when you say local stations, you dont mean those super weak channels 1.1 miles from you ? They must be transmitting on D cells, heh.

No, no, no... ;)
In Colorado Springs, all the towers are on Cheyenne Mountain. I'm adjacent to an area that is blocked by another mountain, and they have had local LP translators for years. That's what that super weak channels are for (and of no interest to me).

You would think being only 8 miles away, I wouldn't have issues. But I must be right on the edge.

Thanks for the suggestions.

and they have had local LP translators for years.
When I saw that on your TVFool, I knew it had to be a very unusual situation, heh.

I'm getting ready to make a custom cut yagi for channel 17. I am using k7mem's design page, and I am wondering a few things:

1: Is it ok if I use 1/8 inch rod for the driven element? I say this because I thought 1/8 inch would be easier to bend than 1/4.

2: what metal should I use for the driven element? I know most antenna parts are aluminum, but since it has to be bent... wouldn't copper be more flexible?

3: How does one attatch the balun to the driven element? Solder it?

4: when the design page gives me element spacing, I'm assuming that measurement is center to center?

5: what's the best thing to use to attatch the elements to the boom? Small brass screws? (I'm using hollow 3/8 aluminum element form old antenna)

I cant figure out the one directly under the helix antenna, or is it just a mast ?

I dont know, but how do those helix work? Do you "aim them like a bazooka?" The Terk TV-55 is like that then. I just saw a vintage table top helix that went for $30 plus shipping on ebay.

http://img.auctiva.com/imgdata/4/0/3/8/1/2/webimg/273626394_o.jpg

I dont know, but how do those helix work? Do you "aim them like a bazooka?"
Yeah, and from most of the helix antenna models Ive seen, most people seem to use them backwards, heh. (in other words, the feedpoint is the front of the antenna) They also generally dont have a wide bandwidth.

The picture you have above is not a true helix antenna. More like a folded dipole with a spiral top.

I'm getting ready to make a custom cut yagi for channel 17. I am using k7mem's design page, and I am wondering a few things:

1: Is it ok if I use 1/8 inch rod for the driven element? I say this because I thought 1/8 inch would be easier to bend than 1/4.

2: what metal should I use for the driven element? I know most antenna parts are aluminum, but since it has to be bent... wouldn't copper be more flexible?

3: How does one attatch the balun to the driven element? Solder it?

4: when the design page gives me element spacing, I'm assuming that measurement is center to center?

5: what's the best thing to use to attatch the elements to the boom? Small brass screws? (I'm using hollow 3/8 aluminum element form old antenna)

What is the URL for k7mem's design page?

What is the URL for k7mem's design page?

http://www.k7mem.com/

you can find the antenna area in the menu to the left, there you can go to a number of areas within that

I'm getting ready to make a custom cut yagi for channel 17. I am using k7mem's design page, and I am wondering a few things:

1: Is it ok if I use 1/8 inch rod for the driven element? I say this because I thought 1/8 inch would be easier to bend than 1/4.

2: what metal should I use for the driven element? I know most antenna parts are aluminum, but since it has to be bent... wouldn't copper be more flexible?

3: How does one attatch the balun to the driven element? Solder it?

4: when the design page gives me element spacing, I'm assuming that measurement is center to center?

5: what's the best thing to use to attatch the elements to the boom? Small brass screws? (I'm using hollow 3/8 aluminum element form old antenna)

you can enter 1/8 for the driven element and get the design
copper if good
solder is best
when fastening metals you would like to use a fastener of the same metal as you are attaching. end result is yo don't want dissimilar metals touching to minimize corrosion. if two metals have to mechanically (but not electrically) touch then you might isolate them from each other with paint, plastic. fasteners of an alloy of one of the metals might be the best you can do.

I'm getting ready to make a custom cut yagi for channel 17. I am using k7mem's design page, and I am wondering a few things:

1: Is it ok if I use 1/8 inch rod for the driven element? I say this because I thought 1/8 inch would be easier to bend than 1/4.

2: what metal should I use for the driven element? I know most antenna parts are aluminum, but since it has to be bent... wouldn't copper be more flexible?

3: How does one attatch the balun to the driven element? Solder it?

4: when the design page gives me element spacing, I'm assuming that measurement is center to center?

5: what's the best thing to use to attatch the elements to the boom? Small brass screws? (I'm using hollow 3/8 aluminum element form old antenna)


I would like to add to Johnposts' good comments.

I've used 1/8 for channel 18, using k7mem's page. Works just fine. If you have slightly less ambition, you might find yourself wanting to use less than the 2.2 wavelength boom (I think) that his page wants. It will complain that your boom is too short. Shorter booms (with less design gain) work for me, although I have no test range hard data to prove it.

I assume you are talking about bending to make the folded dipole for the driven element. 1/4 copper "refrigerator" tubing bends very nicely too, perhaps too easily. There is hard-copper tubing, but I have not tried it. Aluminum tubing is reasonably available. There are tubing benders available, most are for conduit, but I believe some are available for smaller gauge tubing. One crude approach I have used to avoid kinking the tubing at the bends is to flatten it where i want to bend it. The flat part bends very nicely!

In the attic, I did not worry about dissimilar metals. YMMV.

Good luck!
Jay

I have two markets that are almost 180 deg apart in heading. I'd like to put two CM4221s (or CM4228s) back-to-back on the same mast. Will one antenna affect the performance of the other? I will NOT be combining the downleads; each will be separately delivered to an A-B switch. I remember there being something called a "capture area" that recommended antennas be separated vertically on the same mast, but I don't recall the details.


For UHF you shouldn't have too much problems because the screen reflector should isolate the driven elements from each other pretty well but if you have any VHF-hi stations there will be some interaction on those channels for sure.

When using an A/B switch, the coax to the antenna that is switched off is probably shorted or open but either way the length of coax going to the non-selected antenna will act as part of that antenna somewhat. That will hopefully de-tune the non-selected antenna so it won't bother even if there is some leakage through the reflectors.

What is the URL for k7mem's design page?
There is often a problem giving a link to his design page, perhaps because of the javascript. I go to google.com and enter k7mem in the search box. His site should be the first one listed. Look for:

Martin E. Meserve - K7MEM - VHF/UHF Yagi Antenna Design (you can also try entering this)

He also has another page for the antenna feed.

ANALYSIS OF K6STI's HI-VHF 5-ELEMENT YAGI (WITH SWEPT BACK DRIVER):
K6STI (FM Antenna Modeling and Yagi Optimizer) posted an optimized 75-ohm Hi-VHF
Yagi design on our local forum that provided moderate Gain (7.25-9.25 dBi), excellent
F/B (22++ dB) and F/R Ratios (22+ dB) across the ENTIRE Hi-VHF Band (Ch7-13):
http://www.ham-radio.com/k6sti/vhftv.htm
This provides LOTS of suppression of signals coming in from the BACK of the antenna.
And it's very compact: 30-in boom with under 33-in width....so can fit on a balcony....

I constructed a 4nec2 file and ran it....and spun off a 300-ohm Folded Yagi variation:
http://imageevent.com/holl_ands/yagis
Thus far, the designs all assume 3/8-in Aluminum tubing elements....

You'll also find comparisons to 4-Element and much longer 8-Element Yagis per
K7MEM's on-line calculator (DL6WU equations), which only adequately cover
2-3 consecutive channels.
Plus comparisons to other large (100-inch boom) high gain antennas that also
provide full band coverage across Ch7-13, such as a 14-Element LPDA and
Zig-Zag Log Periodic Array variants.....but need lots of real estate....

===================================
ANALYSIS OF HI-VHF FOLDED DIPOLE ELEMENT DIAMETER:
FYI: In my link above, you'll also find an investigation of how many Hi-VHF channels
can be adequately covered using just a Folded Dipole. Varying the element diameter,
I determined a "good" SWR and Net Gain across the entire Ch7-13 band could be
provided after chopping up a 10-ft piece of 1/2-in copper tubing and soldering four
copper angle pieces to form a 28.5-in by 2-in "box" with a (1-in?) opening on one side....

Total cost about $10 incl. a cheap Balun....or see if you can't RECYCLE something....

Also a good exercise for Yagi antenna designers.....how fat do elements "need" to be????

======================================================
IMPORTANCE OF LOW SWR FOR DTV:
You might find the recent post of interest if you don't think SWR is important:
http://www.avsforum.com/avs-vb/showthread.php?p=16653603

ALSO FLAT FREQUENCY RESPONSE ACROSS EACH CHANNEL:
http://www.dielectric.com/broadcast/slotted.asp

Yeah, I know, I worry too much.....fortunately most people are awash in signals....
Time to get back to that EZ-HD (aka RCA ANT751) model.....what a pain.....

===================================
EDIT (17Jun2009 @ 0735): Changed comparisons to K6STI's original vice my Folded Dipole variant.

Yeah, and from most of the helix antenna models Ive seen, most people seem to use them backwards, heh. (in other words, the feedpoint is the front of the antenna) They also generally dont have a wide bandwidth.

The picture you have above is not a true helix antenna. More like a folded dipole with a spiral top.

NO, the helix does NOT have the feedpoint on the FRONT...a TRUE helical antenna has a screen reflector at the back end...and that would be where the feedpoint is. A Helix is a simple and effective antenna....~130 ohm feed.....easy to match to 50 or 75 ohm cable...but the "front" of the helix is NOT the feed point...
Wide bandwidth? You dont call 30-50MHz of bandwidth WIDE??? Compared to a yagi cut to channel, it is ultrawide!

AND the one in the picture a FOLDED dipole?? DO YOU EVEN know what a folded dipole is??? (I think not)

Heh, regarding my history of channel 1 post earlier in this thread, since the transition, I am now getting channel 1-1 on both my converter boxes. Its really WTVE-DT 51-1 (real channel 25), the shopping channel, out of Reading PA with lots of repeater stations. I wonder how they pulled off getting that channel assignment ?

Nobody can review the Blonder Tongue?

Heh, regarding my history of channel 1 post earlier in this thread, since the transition, I am now getting channel 1-1 on both my converter boxes. Its really WTVE-DT 51-1 (real channel 25), the shopping channel, out of Reading PA with lots of repeater stations. I wonder how they pulled off getting that channel assignment ?It may just be a malfunctioning PSIP enconder at the station. We had a similar problem in DC, but the station is now reading 47.1.(It used to be display as channel 1, 8, & 47-very annoying)

I've used 1/8 for channel 18, using k7mem's page. Works just fine. If you have slightly less ambition, you might find yourself wanting to use less than the 2.2 wavelength boom (I think) that his page wants. It will complain that your boom is too short. Shorter booms (with less design gain) work for me, although I have no test range hard data to prove it.

I used his design page to build a yagi for channel 8 and it consisted of a director, reflector, and folded dipole. The complete antenna was made with 24" of 3/4" PVC boom and 10 AWG solid cooper electrical wire elements.

It works great for 8 and 12.

Im going to try one of those 5 element folded hi VHF yagis, thanks for posting hollands.

a TRUE helical antenna has a screen reflector at the back end.
Putting on a reflector changes the equation from a PURE helical antenna like this:
http://img188.imageshack.us/img188/1238/hel10ua.jpg

You dont call 30-50MHz of bandwidth WIDE??? Compared to a yagi cut to channel, it is ultrawide!
Thats wider bandwidth than Ive seen quoted on something with decent gain. How many loops and whats the length ? Yes, the helix bandwidth is wider than a yagi, but nowhere near a bowtie or whats needed to cover the UHF TV band. Ive seen wider bandwidth helix's with varying loops, but the gain was not impressive.

AND the one in the picture a FOLDED dipole?? DO YOU EVEN know what a folded dipole is??? (I think not)
The picture you have above is not a true helix antenna. More like a folded dipole with a spiral top.
Didnt say it was a folded dipole, but more like one. What do you want to call the thing, heh ?
(Hmm, there should be a formal name for that style antenna as I recall seeing some 1920s/30s short wave antennas similiar to it)

ANALYSIS OF K6STI's HI-VHF 5-ELEMENT YAGI (WITH SWEPT BACK DRIVER):
K6STI (FM Antenna Modeling and Yagi Optimizer) posted an optimized 75-ohm Hi-VHF
Yagi design on our local forum that provided moderate Gain (7.25-9.25 dBi), excellent
F/B (22++ dB) and F/R Ratios (22+ dB) across the ENTIRE Hi-VHF Band (Ch7-13):
http://www.ham-radio.com/k6sti/vhftv.htm
This provides LOTS of suppression of signals coming in from the BACK of the antenna.
And it's very compact: 30-in boom with under 33-in width....so can fit on a balcony....
The high F/B ratio of this antenna has seriously tempted me to try this antenna. It seems short enough that I could use a PVC boom. Does anyone have any tips or ideas on how to best implement the swept-back feed arrangement?

One more thing -- If my co-channel problem is at the high end of the VHF band (11 and 13) do I even need the swept-back feed? Brian says that bent driven elements increase F/B at the low end of the band.

So, I bought an Antennas Direct DB4 antenna a while back, threw it up in the attic attached to a piece of pvc pipe and aligned it using the signal bars on my tv. Quick......Done. I was getting 8 - 10 bars out of 10 on all UHF digital channels so I was really happy. That combined with NetFlix via a Roku box and goodbye cable. Then the DTV June 12th transition occurred and three channels moved to the upper VHF band (RF channels 7, 11 and 13). I didn't see that one coming, along with my ignorance of what an antenna advertised as "HDTV" meant (UHF, VHF, Joe'sHF, NOHF, whatever.....All I ask for is to get "Two and a half men" again on channel 11). I now get these channels intermittently. So, I am thinking of either adding a small cheap upper VHF antenna (AntennaCraft Y5-7-13 seems highly recommended) or just throwing out the DB4 and putting up something like a Winegard HD7694P. What is the better choice, and is either one acceptable, considering that I want to keep it in the attic for various reasons, and I am trying not to get something that is overkill. What combiner would you recommend? I have attached my Digital station report from tvfool (All I care about are the stations on the two main NYC broadcasting towers around the 72 degree heading). Thanks.

I was hoping someone could recommend me an antenna. My wife and I just bought a house that is 100% concrete (Inside and Outside walls). We have not moved in yet (renovations will continue for a few more weeks) so I have not been able to try the reception. We life right outside Orlando, FL but do not want to spend the $50 a month for Cable TV, just internet for now. In the back of the house, there is a 10-12' pole with a outdoor light on it. I was thinking about putting a small antenna on it towards the top and running the cable along the outside of the house. It would have to be pretty minimal looking or my wife would not be too pleased. Any suggestions?

http://www.tvfool.com/?option=com_wrapper&Itemid=29&q=id%3d663d6fcf3117b6

So, I bought an Antennas Direct DB4 antenna a while back, threw it up in the attic attached to a piece of pvc pipe and aligned it using the signal bars on my tv. Quick......Done. I was getting 8 - 10 bars out of 10 on all UHF digital channels so I was really happy. That combined with NetFlix via a Roku box and goodbye cable. Then the DTV June 12th transition occurred and three channels moved to the upper VHF band (RF channels 7, 11 and 13). I didn't see that one coming, along with my ignorance of what an antenna advertised as "HDTV" meant (UHF, VHF, Joe'sHF, NOHF, whatever.....All I ask for is to get "Two and a half men" again on channel 11). I now get these channels intermittently. So, I am thinking of either adding a small cheap upper VHF antenna (AntennaCraft Y5-7-13 seems highly recommended) or just throwing out the DB4 and putting up something like a Winegard HD7694P. What is the better choice, and is either one acceptable, considering that I want to keep it in the attic for various reasons, and I am trying not to get something that is overkill. What combiner would you recommend? I have attached my Digital station report from tvfool (All I care about are the stations on the two main NYC broadcasting towers around the 72 degree heading). Thanks.

Before purchasing another antenna, try widening the reflector on your existing DB4 to 32"-36". As your antenna is protected in your attic, aluminum foil would work for the experiment. Four stations in El Lay reverted to their VHF-hi assignments, and I've widened reflectors on half-a-dozen 4-bay antennas to provide enough additional VHF-hi gain to make them usable.

Here's a link containing photos: http://www.avsforum.com/avs-vb/showpost.php?p=16638268&postcount=4934

I was hoping someone could recommend me an antenna. My wife and I just bought a house that is 100% concrete (Inside and Outside walls). We have not moved in yet (renovations will continue for a few more weeks) so I have not been able to try the reception. We life right outside Orlando, FL but do not want to spend the $50 a month for Cable TV, just internet for now. In the back of the house, there is a 10-12' pole with a outdoor light on it. I was thinking about putting a small antenna on it towards the top and running the cable along the outside of the house. It would have to be pretty minimal looking or my wife would not be too pleased. Any suggestions?

http://www.tvfool.com/?option=com_wrapper&Itemid=29&q=id%3d663d6fcf3117b6

I am jealous of how close you are to so many stations. So the wife doesn't want something huge and gawdy looking out there, eh? Well, you are in luck, you have so many channels near by, you should be able to get by with a relatively small antenna, and you may not even need any amplification.

I have a far messier situation and I am getting by with a DB2 antenna. That being, two pairs of bow-ties. They are cheap to buy, even cheaper to make. Just point the thing toward 118 degrees (magnetic) and you should get all those green stations crystal clear.* You may very well pick up some of the other stations from behind, they you are getting into some bad colors at that point.


*the art of antenna reception involves black magic, nothing is guaranteed.

Before purchasing another antenna, try widening the reflector on your existing DB4 to 32"-36". As your antenna is protected in your attic, aluminum foil would work for the experiment. Four stations in El Lay reverted to their VHF-hi assignments, and I've widened reflectors on half-a-dozen 4-bay antennas to provide enough additional VHF-hi gain to make them usable.

Here's a link containing photos: http://www.avsforum.com/avs-vb/showpost.php?p=16638268&postcount=4934

Nice work Arbie! Can you shoot a picture of the 4221 mod from the side and from the rear? I would like to see how you made your connections and use similar for attaching to a DIY mclapp 4-bay. I am using the same hardware cloth for my reflector. Do you need a frame to keep the reflector flat?

thanks!

Rick

Which antenna is better for 12 & 13:

YA-1713
Y10-7-13

I am trying to pick-up WPRI/13 and WNAC/12 from Mystic, CT (06355). I have a YA1713 there now, but it was not reliable for WPRI/13 in the summer.

I'm pointing the existing YA1713 towards New Haven at the moment (for WTNH/10 & WEDN/9 at an off-angle) and will combine 9/10 with 12/13 using a Tin Lee custom combiner.

I know that the gain chart for the 1713 drops off at 13, so I'm wondering if the 10-7-13 might serve me better. Are there any other options I should consider? (besides VIP-class, etc.)

Thanks,

I know that the gain chart for the 1713 drops off at 13, so I'm wondering if the 10-7-13 might serve me better. Are there any other options I should consider? (besides VIP-class, etc.)
I think the "gain chart" most people reference shows a significant dropoff for 13, but Winegard's specs indicate otherwise. In fact, they show it doing best on 13 (10.3 dB on 13 compared with 10.0 on 9 and 11, and 9.1 on 7).

For one data point, I'm 40 miles away from KAKW (transmitting on 13) and my YA-1713 is aimed at the Austin tower farm nearly 30º skewed from the KAKW tower. With an HDP-269 preamp into my D* HR20, I regularly get 95-100% signal strength on KAKW despite the "bad aim." I don't think that's poor performance on channel 13, though admittedly we're LOS to that tower.

Nice work Arbie! Can you shoot a picture of the 4221 mod from the side and from the rear? I would like to see how you made your connections and use similar for attaching to a DIY mclapp 4-bay. I am using the same hardware cloth for my reflector. Do you need a frame to keep the reflector flat?

thanks!

Rick


I second IDRicks questions about the neat, clean, straight, flat mounting job on the screen.

I think the "gain chart" most people reference shows a significant dropoff for 13, but Winegard's specs indicate otherwise. In fact, they show it doing best on 13 (10.3 dB on 13 compared with 10.0 on 9 and 11, and 9.1 on 7).
Yeah, holl_ands, who has a YA1713 also, reports no drop off on 13 either. Ken Nist may have had an earlier production run of that antenna.

Nice work Arbie! Can you shoot a picture of the 4221 mod from the side and from the rear? I would like to see how you made your connections and use similar for attaching to a DIY mclapp 4-bay. I am using the same hardware cloth for my reflector. Do you need a frame to keep the reflector flat?

thanks!

Rick

I second IDRicks questions about the neat, clean, straight, flat mounting job on the screen.

The CM-4221's mast mounts are u-shaped brackets, the corner of which has a horizontal cut that is crimped over the reflector. It takes maybe a minute to uncrimp the bracket corners, replace the reflector, and recrimp the bracket corners. I've attached the best closeup I have of the upper bracket, with the crimp in the upper-right. I'm sure someone else can provide a better picture/drawing of the brackets.

Once uncoiled from the 25' roll and flattened, my welded wire was stiff enough not to require a frame. But, as I have extra material, I roll the top and bottom inch of the reflector back on itself to provide extra horizontal stiffness.

rb

I inserted an RF Attenuator and observed how much attenuation it took before the video and sound
carriers were lost, using ANALOG Ch7, 9, 11 & 13 signals from (70-miles away) Mt Wilson in L.A.
If there was a significant gain loss across Ch13, the sound carrier would be lost with less
attenuation inserted than the video carrier. I did NOT observe any significant different for
Ch13....and there wasn't much difference compared to other Hi-VHF channels either:
www.imageevent.com/holl_ands/wgya1713

Conclusion: Gain drop across Ch13 is an artifact of the oversimplified NEC simulation model.

Thanks for posting the image, Arbie! Works very well for you! To bad CM does not sell the mounting brackets separate from the 4221. CM has a universal mount that could perhaps be modified to give a similar mounting strategy. Food for thought.... Thanks again!

Can anyone help me with reception problems? I live in West Hartford, CT. My TV fool analysis is here: http://www.tvfool.com/?option=com_wrapper&Itemid=29&q=id%3d663d4ab99e0ce2

I am only able to put the antenna indoors. Currently, I have an RCA ANT1050, and a Philips MANT940. Both antennas acquire a semi-reliable signal on cbs and fox. The abc signal is poor, and I cannot receive NBC at all. Another problem with my reception is that the Springfield channels appear to be conflicting with the Hartford stations that I want to receive.

Once uncoiled from the 25' roll and flattened, my welded wire was stiff enough not to require a frame. But, as I have extra material, I roll the top and bottom inch of the reflector back on itself to provide extra horizontal stiffness.
What type and size of screen are you using?

SORRY! I didn't see the information at the link you posted earlier.

I am only able to put the antenna indoors. Currently, I have an RCA ANT1050, and a Philips MANT940. Both antennas acquire a semi-reliable signal on cbs and fox. The abc signal is poor, and I cannot receive NBC at all. Another problem with my reception is that the Springfield channels appear to be conflicting with the Hartford stations that I want to receive.
Have you taken a look at EV's thread on indoor antennas?

http://www.avsforum.com/avs-vb/showthread.php?t=1037779

Have you taken a look at EV's thread on indoor antennas?

http://www.avsforum.com/avs-vb/showthread.php?t=1037779
The thing is, I dont even know what type of antenna to chose. I'm guessing directional to avoid picking up Springfield stations, but then I might miss some of the other ones in my area.

I would try an RS UFO, I dont know which direction the Springfield stations are, but you should be able to pick up quite a bit in the yellow at 220ish degrees.....and reaim for the stations huddled at 25ish degrees.

There is a chance a ClearStream1 Convertible without its reflector giving you less gain in one direction but giving you bi directional performance would work as a set and forget solution, but probably with an additional amplifier needed. You could also amp an mclapp improved 4 bay bowtie (without reflector) and get similar results.

This all depends on you not having building materials degrading your signals.

Dont forget to look for sweet spots.

Conclusion: Gain drop across Ch13 is an artifact of the oversimplified NEC simulation model.

Thank you very much for the info. However, I may still try the Y10-7-13 as I already have a YA1713 there and would like to compare performance.

Arbie,

Thanks for the info, especially the no cost alluminum foil method just to see if it helps. When I get a chance I will give it a try.

Thanks for the help, I will try the UFO.

Hi,
I have a radioshack 1892 UFO antenna and a Zenith dtt901 dtv converter. I got 37 channels but some of the channels go in and out from time to time even after I adjusted the setting in my antenna, and I also want to get more channels too. Can I use preamp like CM7777 with this indoor antenna? Or should I use just an amp? What is the best preamp? What is the best amp? What do you think of the motorola signal amplifier?

Thanks.

The CM7777 pre-amp is designed for outside antennas with long cable runs. It would not be a good choice for your situation. If you want to try a DA, look at the CM3410.

No need to stack another amp on the RS 1892 UFO. Bad idea.

You should get a longer 12 or 25 ft of coax and look for a sweet spot, you can look for a sweet spot within the 6ft provided coax range as well.

A half a foot up down left right forward back can make a big difference. Also windows facing the towers are prime locations likely to improve reception.

Is it a rule not to stack a preamp or amp to an amped indoor antenna like RS 1892 ufo? Will preamp or amp ever improve its reception?

Any more ideas how to improve reception with RS 1892 ufo? I already played with the channel setting in the antenna.

No need to stack another amp on the RS 1892 UFO. Bad idea.

You should get a longer 12 or 25 ft of coax and look for a sweet spot, you can look for a sweet spot within the 6ft provided coax range as well.

A half a foot up down left right forward back can make a big difference. Also windows facing the towers are prime locations likely to improve reception.

Yes, it's a rule. There's really no way an additional amp can improve the signal, it can only make it worse. For TV reception, you want the signal as clear as possible, not as loud as possible.

Think of it like putting two bull-horns together - the extra bull-horn might make things louder, but the sound won't be clearer. If anything the sound quality will be worse, possibly much worse (screeching and distortion).

At what distance between outdoor antenna and TV, is a preamp needed?
What coax should be used?

HDTVPrimer recommends a pre-amp for any cable run over 20 feet.

The pre-amp should be as close to the antenna as possible - mounted right on the antenna mast is best.

RG6 cable is generally recommended. Some people recommend quad-shield RG6, but with a decent pre-amp I don't think it makes too much difference.

At what distance between outdoor antenna and TV, is a preamp needed?
What coax should be used?

If you are receiving only weak signals a low noise preamp can provide improvement with any length of cable. This is because the receiver/TV almost always has a higher noise figure than them preamp.
John

here's my situation:

- i'm only 8 miles away from the towers.
- line of sight is obstructed by a hill in my neighbourhood.
- i can only use an antenna indoors.
- i've tested 4 antennas so far.
- with the exception of the home-made one, all had built-in amplifiers.

antennas i've tested so far:

1) home-made loop (no VHF reception). <-- cheap, simple and efficient for UHF! :)
2) Terk TV55 (neither VHF nor UHF reception).
3) RadioShack UFO (VHF reception is 40% on the sweet spot).
4) Terk HDTVa (VHF reception is 40% on the sweet spot). <-- my favourite one!

in sum: UHF reception is fine, but i need help with high VHF!
now focusing on the best performers (HDTVa and UFO) and the problematic high VHF band:

- if amp is off, neither HDTVa nor UFO can receive VHF!
- with amp on (and antenna on the sweet spot), high VHF signal is 40% only!
- this shows amplification makes a HUGE difference!
- a displacement of an inch turns the sweet spot into a *bitter* one for VHF!
- if weather changes, VHF signal drops to zero....even on the sweet spot! :mad:
- due to space constraints, the use of 2 diff antennas is unfeasible.


what i'm looking for is a suggestion on how to deal with the weak high VHF reception (UHF is fine!). like i said, it must be a solution deployable *indoors*. the options i could think of so far were:

a) get a new antenna with better high VHF reception (Winegard HD-1080 (http://www.solidsignal.com/prod_display.asp?PROD=HD-1080), perhaps?).
b) get a good amplifier (which one?) to replace the HDTVa's one (favourite antenna).
c) get a better high VHF antenna *plus* a good amplifier (which one?).

any suggestions? thanks in advance!

HDTVPrimer recommends a pre-amp for any cable run over 20 feet.

As General McAuliffe said "NUTS!" (I'm a veteran of the 101st ABN, '77-'78)

20' ft of cable is only 1.1-1.5 dB loss (RG6) loss. It's silly to put a 15-25 dB pre-amp on there to overcome that unless there are other factors.



The pre-amp should be as close to the antenna as possible - mounted right on the antenna mast is best.


Absolutely correct. It is important to boost the signal before any (or as little as possible) of it is lost. Once lost due to attenuation, it cannot be resurrected.


RG6 cable is generally recommended. Some people recommend quad-shield RG6, but with a decent pre-amp I don't think it makes too much difference.

As long as you're not in an electrically noisy environment, "regular" RG6 is "good enough".

First try reducing the telescoping dipoles to 30ish inches and deploy them out flat and at other angles in a V upwards and or towards the towers at perpendicular position.

But you will probably need to get a better VHF antenna and a UVSJ combiner (UHF VHF Signal Joiner) to combine the VHF antenna signal and your Terk HDTVa for the UHF signal into the same cable. Just fold up the Terks dipoles and stow away.

You can build the VHF yagi that Hollands has posted. Small and very good.

You can build the VHF bowtie that mclapp has posted. Small and pretty good.

You can get a VHF only yagi like the AntennaCraft Y5-7-13 (http://www.antennacraft.net/Yagi.html) with a 60 inch boom length and mount on the ceiling.

Or you can try the EZ HD or RCA ANT751 clones and add an off board amplifier like the Channel Master 7777 or the Winegard 269.

First try reducing the telescoping dipoles to 30ish inches [...]

i've spent a great deal of time moving the antennas around and messing with both their dipoles' length and angle. i've found that an angle of 150-120 degrees works best here. best length is 1 to 1.5 feet. so the 40% signal strength i get (when the antennas are at the "sweet spot") already takes into account the optimal angles and lengths. i've also tried different heights (stacking boxes) and distances from the wall.

You can build the VHF yagi that Hollands has posted. Small and very good. You can build the VHF bowtie that mclapp has posted. Small and pretty good.

due to space constraints (apt in NYC), i cant use anything too big. i'll search the forum for those.

Or you can try the EZ HD or RCA ANT751 clones and add an off board amplifier like the Channel Master 7777 or the Winegard 269.

hey, i was looking for a small antenna like that on www.solidsignal.com (http://www.solidsignal.com), but the only antenna of manageable size i found there (for use indoors) was the http://rover.ebay.com/ar/1/711-53200-19255-0/1?mpt=1457438334&adtype=1&size=1x1&type=3&campid=5336055023&toolid=10001 HDTVo (http://www.amazon.com/gp/redirect.html?ie=UTF8&location=http%3A%2F%2Fwww.amazon.com%2Fs%2Fref%3Dnb_ss_e%3Fu rl%3Dsearch-alias%253Delectronics%26field-keywords%3Dhdtvo%26x%3D0%26y%3D0&tag=5336055023-20&linkCode=ur2&camp=1789&creative=9325). has anyone here had experience with that one? the RCA ANT751 looks fine too.

HDTVPrimer recommends a pre-amp for any cable run over 20 feet.
The key of course is a quality, low noise preamp.

20' ft of cable is only 1.1-1.5 dB loss (RG6) loss. It's silly to put a 15-25 dB pre-amp on there to overcome that unless there are other factors.

The other factor is VSWR.

Even so, the number of people who really need an extra 1-2 db of performance is small.

Re Preamp and System Noise Figure: fol. is very informative presentation:
http://www.digitalhome.ca/forum/showthread.php?p=888237
Scroll down a few posts to find chart with multiple Preamp examples,
and scroll up for expanations....

Link to tczernec's spread sheet no longer works. I should probably put
one on my "files" page. Till then, here are the equations:
http://www.digitalhome.ca/forum/showthread.php?p=879270

PS: The Preamp Overload Calculator they refer to is found in my "files" page:
www.imageevent.com/holl_ands/files

There is another factor - the noise figure advantage of the pre-amp. Combine the two factors and even at 20 feet the improvement (3 dB or more) starts to become compelling. Above 20 feet it becomes even more compelling.

I'd agree a 25 dB amp on a 20 foot cable run is overkill, but a 15 dB amp would be just about right - just enough to overcome the cable loss and the TV's noise figure, plus another 10 dB.

i dont have experience with amps and i wanna make sure i get something that will improve my VHF signal without messing with my converter box (CM-7000). i wanna boost the signal coming out of an indoor antenna and the cable run will be short (about 10 feet).

so my question is: is there an amount of gain that can damage my converter? is it safe for me to buy the CM 7777 amp for an indoor application? if not, which amp should i get?

another question: my Terk HDTVa came with an amp. does anyone know what is the gain of that amp?

i dont have experience with amps and i wanna make sure i get something that will improve my VHF signal without messing with my converter box (CM-7000). i wanna boost the signal coming out of an indoor antenna and the cable run will be short (about 10 feet).

so my question is: is there an amount of gain that can damage my converter? is it safe for me to buy the CM 7777 amp for an indoor application? if not, which amp should i get?

another question: my Terk HDTVa came with an amp. does anyone know what is gain of that amp?
Actual DAMAGE...no, at most the output is a small fraction of a volt....
No, a Preamp won't help and could hurt with only 10-ft of cable....

The "a" means the Terk is amplfied, the unamplified model ends in an "i".
Terk/Audiovox website doesn't provide gain numbers (oh so typical for Urp...Terk).

When you use more than one Preamp, tuner OVERLOAD is likely, when means that
intermod noise signals can prevent reception of weak signals.
[I can't hear you, shout louder into your cellphone!!!!!! Oh so wrong....]
If towers are within say 10 miles of you, the HDTVa might even be overloaded....

Preamp Gain selection depends on the strength of signals from local stations and
loss due to indoor location.....YMMV....YMMV....YMMV....

High gain Preamps (e.g. highly rated CM7777) are for RURAL use, not Urban...
and many Suburban areas would benefit from the lower gain alternatives....

And due to higher man-made noise floor (esp Ch2-6), Preamps
are less likely to help VHF reception than UHF....

When you use more than one Preamp, tuner OVERLOAD is likely, when means that
intermod noise signals can prevent reception of weak signals.

i'm not planning to chain them. i wanna buy an amp to use in place of the amp provided with the HDTVa (it comes as a separate item in the box....its use is optional).

so, if a pre-amp (such as the 7777) cannot cause damage to the converter, should i buy the with the highest gain that my budget can afford? sorry, but i know nothing on the subject.... :confused:

I read back through most of your posts....
So you're in an apt, 8 miles N of Empire State Bldg in NYC.... Which floor? Facing ESB?

It's likely they're still working on the VHF transmitters...give it a week or two....
Out on the West Coast, two of L.A.'s VHF stations are still at low power....
I can't imagine working on that mass of metal they call an "antenna" on top of the ESB...

Did you post the www.tvfool.com results URL for your location???

Did you try the Terk HDTVa without the Preamp module???

> So it's likely they're still working on the VHF transmitters...give it a week or two...

my concern is that FCC bureaucracy will drag this problem for months.... :-\

> Did you post the www.tvfool.com (http://www.tvfool.com) results URL for your location???

no because i get all UHF channels. only prob is the VHF ones. TVFool puts those channels on the green area as LOS.

> Did you try the Terk HDTVa without the Preamp module???

yep. the amp doesnt affect the UHF channels much, but without it, RF-13 drops from 40% to zero! it's paramount to high VHF in my apt.

If TVFool says it's LOS, then that hill isn't in the way....which means
you're awash in signal, even if apt bldg attenuates signal (up to 25 dB).
I don't see any other TV stations from Hackensack to the Bronx, so ESB is overload source.
Although unlikely, WNYU-FM in the Bronx might be an overload issue, depending on where you are.

I would suspect multipath, which means try to block signals
bouncing in from all around you, such as a metal reflector screen
(temporarily try some cooking sheets or Al foil....)

Here's an example UHF "antenna in a box"....VHF will be a lot bigger:
http://www.prism.gatech.edu/~wn17/

Higher gain antenna also helps in this respect, but needs lots of room...

At least one well known apt dweller found a WINDOW mounted Loop Antenna
worked better than many other indoor antennas he tried. Here's a design for FM Band
(above CH6) which can be shrunk down for Hi-VHF...roughly HALF the diameter.
And here is a UHF Loop that can be increased in diameter by a factor of 2 to 2.5 for Hi-VHF:
http://www.hdtvprimer.com/ANTENNAS/Loop.html
Loop Antenna Calculator can be found here (enter 192 MHz...or your choice):
http://ka1fsb.home.att.net/loopcalc.html
[NEC sim modeling exercise is on my TO DO list...unless someone else volunteers...]

I need recs for this situation. Friend of mines, place in the mountains of North Carolina, near Mt. Mitchell.

Old Mill house is metal sheathed.

http://www.tvfool.com/?option=com_wrapper&Itemid=29&q=id%3d7f1480d77d8eb6


Im thinking a Winegard 7084p, 7082p, or 7080p with a Channel Master 7777 amplifier and a rotor.

If TVFool says it's LOS, then that hill isn't in the way....which means
you're awash in signal, even if apt bldg attenuates signal (up to 25 dB).

TVFool is wrong. i live on the 3rd floor, but even if i went to the building's roof above the 5th floor, i would still not see downtown Manhattan. as a matter of fact i would not see anything besides the hill where Tryon Park is.

so the building's structure can attenuate up to 25db?! wow. that a lot...

I would suspect multipath, which means try to block signals bouncing in from all around you, such as a metal reflector screen (temporarily try some cooking sheets or Al foil???).

given the number of buildings, multipath is a likely culprit too, but that hill is a bummer. i remember looking the terrain profile at TVFool and it showed my location as "hole" on a foot hill.

Higher gain antenna also helps in this respect, but needs lots of room...

i've been considering a diff antenna, but given i can ony use it indoors, i cant buy something too big. EscapeVelocity suggested the RCA ANT751 which isnt too big. i've been considering the Winegard HD-1080 (http://www.summitsource.com/winegard-hd1080-2-bay-bowtie-uhf-high-band-vhf-antenna-hdtv-two-bay-aerial-bow-tie-outdoor-roof-top-local-signal-bow-tie-red-zone-part-hd1080-with-coax-cable-p-7048.html). what you think?

my plan was to first try an amp on the HDTVa i already own. if that didnt work, i would try a new antenna with more emphasis on VHF.

i'm also considering making a whiskers VHF antenna tomorrow. i came a cross a PDF here in forum called "2 Bay VHF-HI.pdf". that seems an easy antenna to build.

(temporarily try some cooking sheets or Al foil....)

i tried a reflector made with cardboard and tinfoil. the size is about 18"x36". it influences the UHF signals but not the VHF ones. i guess the size isnt right for high VHF. i can make another tinfoil reflector. which size should i make it? at which distance from the antenna should i place it?

Here's a design for FM Band
(above CH6) which can be shrunk down for Hi-VHF...roughly HALF the diameter.

did you mean to attach an image?

25 dB is largest number measured for a modern, well shielded Office Bldg.
You're probably a lot less, esp high up...

Bigger than the Rabbit Ears....more is better....big pizza tins or bigger???
[Now my mouth is watering for some of that NYC pizza we can't get.....]
Try about 3-5 feet from the antenna....but if 2 feet is all you got.....

Scroll on down beyond the Loop Antenna azimuthal gain charts. It's from:
http://www.hdtvprimer.com/ANTENNAS/COMPARING.html

If you have access to IEEE documents, here's a low-VSWR design from 25-years ago
for entire VHF band that inserts a capacitor in the loop for tuning VSWR:
http://ieeexplore.ieee.org/Xplore/login.jsp?url=http%3A%2F%2Fieeexplore.ieee.org%2Fstamp%2Fsta mp.jsp%3Ftp%3D%26isnumber%3D%26arnumber%3D1143327&authDecision=-203

Ah ha, Tyron Park....when he was 19, I took my son on one of my
DC/Philly/NYC work trips...
we visited The Cloister's Museum...reminded me of Musee de Cluny in Paris...

Care to provide nearest cross streets....that's a monster hill....

Im thinking the Winegard 7082p with the CM 7777 amplifier, but what rotor?

Ah ha, Tyron Park....when he was 19, I took my son on one of my
DC/Philly/NYC work trips...
we visited The Cloister's Museum...reminded me of Musee de Cluny in Paris...

Care to provide nearest cross streets....that's a monster hill....

Cloisters look really nice. i remember reading somewhere that the whole structure was brought from Europe stone by stone and rebuilt on the top of the hill.

i'm near the foot of that hill.

do you think the Winegard HD-1080 or the RCA ANt751 used indoors could get me a better high VHF result?

and regarding the CM7777, should i get it or is it too much gain? i wish those amps had a knob to control the gain....

Which foot??? Can you be just a LITTLE more precise????
I'm not looking for an address, just trying to double check TVFool...

broadway + dyckman.

this is the "foot" of the hill. notice the crater covered with green on the far right of the image. just 10 blocks north of it the signal is way better.

http://www.tvfool.com/modeling/tmp/618a/71a/efc7784/POST-WNET-DT.png

TVFool results for broadway + dyckman:
http://www.tvfool.com/?option=com_wrapper&Itemid=29&q=id%3d618a1ca3f6f010

Yup, you're awash in signal strength. If you click on say Ch11 you can
see the terrain profile. It just glances across Wadsworth Terrace.
http://www.tvfool.com/modeling/tmp/618a/1ca/3f6f010/POST-WPIX-DT.png
[Why does yours look different than the above?????]

Even if it's blocked by the hill, there still will be lots of signal.
Based on the profile, I have no reason to doubt TVFool results...
PS: Radio signals follow a path that is 4/3 that of the Earth's radius,
which bends a little....so Radio LOS may not be visual LOS.

Of course, if the ESB transmitters are at low power....or only some
of the antenna panels around the ESB are activated, it could be less.

[While waiting, I was looking at an even worse location: El Rancho
Jubilee (restaurant?) at 10 Hillside Ave. It's as much as 10 dB worse
than you, but still awash in signal strength.]

PS: You can also see signal strength in surrounding area here:
http://www.tvfool.com/index.php?option=com_wrapper&Itemid=90

when you say "awash" you mean too much signal? i can get the UHF channels with ease, but the high VHF ones have been a battle since June 12 when ABC, CW and PBS went back to VHF land.

btw, the terrain profile makes you think you can spot the ESB.... i assure you that it's impossible even with a binocular because the hill in in the way. the TVFool info is wrong.

when you say "awash" you mean too much signal? i can get the UHF channels with ease, but the high VHF ones have been a battle since June 12 when ABC, CW and PBS went back to VHF land.

btw, the terrain profile makes you think you can spot the ESB.... i assure you that it's impossible even with a binocular because the hill in in the way. the TVFool info is wrong.
Anything stronger than -30 dBm is very strong and -20 dBm will overload most Preamps,
meaning WEAK stations will be hard to receive....which is not the case for CH7/11/13.
In your location, I wouldn't use a Preamp...or an amplified antenna...

Here are TVFool results for El Rancho Jubilee at 10 Hillside Ave:
http://www.tvfool.com/?option=com_wrapper&Itemid=29&q=id%3d618ab4c8cb684c
For sure it's not LOS....but still very strong signals (NM is nearly 50 dB).
Further away from the hill, the signals levels increase as the diffraction
angle is less.

When you're in a valley (you and me both), the signals can bounce off
hills "behind" you as well as glance off hills on either side (between
you and ESB). This is multipath....

I'm quitting for now....man i miss Leno....

interesting fact about the difference between real LOS and radio LOS.

this is one of the reasons i didnt wanna post TVFool's data.... it might have some accurate data, but it sure has inaccurate ones too. the NYC thread is packed with people who cant receive the high VHF channels ABC, CW and PBS. the VHF figures on the table do not represent the reality.

well, TVFools data wont help me.... i need to know what is the best course of action to get the high VHF channels. i'll try making a bowtie tomorrow.

regarding the amplifiers, now i dont know if i should buy it anymore.... you say that it will make things worse. :( that sucks! i dont care for ABC at all. and i rarely watch CW, but i'd really like to improve the reception of ch 13.

i'm close to giving up.... i should read more, anyway.


I'm quitting for now....man i miss Leno....no worries. he'll be back soon enough. i always liked Conan better so i'm fine. he's more "behaved" now which looks strange to me accustomed to his clownness. so, in a way, i miss Conan. :)

my concern is that FCC bureaucracy will drag this problem for months.... :-\

To their credit, so far the FCC seems to be moving very quickly in response to situations where there is widespread loss of reception.

I hate to sound stupid, but has anyone suggested you try a regular old non-amplified rabbit ears? It may be your Terk is just lousy on VHF.

With signals that strong you shouldn't need an amplifier, and it's generally better to not use an amp if you don't need to - avoids the whole intermod distortion/overload issue.

FYI: L.A. area "GCG Communicator" reported many Hi-VHF reception problems (Ch11/13)
were solved by collapsing Rabbit Ears to about 14-inches (each)...fully extended is for Ch2-6:
http://www.avsforum.com/avs-vb/showthread.php?p=16681974
It won't be posted on-line for a couple weeks--ya gotta subscribe to get it "real time":
http://www.bext.com/_CGC/

Here are Rabbit Ear lengths (tip-to-tip when completely horizontal):
http://www.kyes.com/antenna/rabbitear.html
He recommends laying the ears down completely horizontal....however in URBAN
environments it may help to try 45-degrees....with additional extension.

Many stations are upgrading to circular polarization (both Horiz & Vertical) which
means 45-degree antenna has a chance of receiving one, the other or both.
FCC allows stations to DOUBLE their total power if circular polarization....it's
effectively two separate antennas driven by two separate transmitters.....
EACH at the authorized ERP level if it were strictly horizontally polarized
[and I'm sure someone will point out exceptions to this general "rule"...]

You can check whether a station is Circular (C) or Elliptical (E) in fol. spread sheet:
http://www.rabbitears.info/ss/
Although there are some C & E UHF stations in NYC, the VHF stations have not yet
upgraded.....as MobileTV rolls out this year they may decide to finally upgrade....

HDTVPrimer has guidelines for use of RabbitEars:
http://www.hdtvprimer.com/ANTENNAS/RabbitEars.html#Getting
Those lengths look way too high....must be for a full-wave dipole vice usual half-wave.

K6STI analyzed Rabbit Ears with 45-degree angle for FM Band using NEC sim:
http://www.ham-radio.com/k6sti/rabbit.htm
For 90 MHz, tip-to-tip when horizontal was 43-in and 40-in when rotated to 54-deg.
Transposing to say 192 MHz, horiz tip-to-tip is 20.16-in and 18.75-in after rotating
to angled position. [192 MHz is in middle of Hi-VHF Band, see KYES link above.]

So try all of the above methods and let us know.....

Although I didn't specifically do Rabbit Ears, I did analyze SWR for
various element diameters in a Folded Dipole:
http://www.avsforum.com/avs-vb/showthread.php?p=16657940
You can see that skinny wire Folded Dipoles only cover 2-3 channels
with reasonable SWR (under 2 and preferably under 1.5).

===========================================
Surely you know an "HDTV Ready" antenna should have low VSWR,
something typical Rabbit Ears are hopelessly impossible providing
unless you have the skills to tweak every time you change channels.
[Yes, there IS a difference between HDTV and Analog TV antennas.....]

Just one of the several bones I've picked with JER3 (Antennas Direct):
http://www.avsforum.com/avs-vb/showthread.php?p=16653603
They shouldn't be advertising VHF coverage in ClearStreams if they
can't provide Gain, Azimuthal coverage and VSWR info.....

TVNewsDay reported "VHF Throws Wrench In DTV Transition":
http://www.tvnewsday.com/articles/2009/06/18/daily.5/?page=1
I posted fol. info in the L.A. thread re VHF problems re VSWR & coverage prediction:
http://www.avsforum.com/avs-vb/showthread.php?p=16681206

=====================================
Of course the best advice right now is to sit tight and wait a couple weeks for the
VHF transmitters to sort out their Analog to DTV upgrades...it isn't a simple switch...

I am using the older CM4228 with CM7777 and am 65 mi from channels 7, 8,55.
I have clear shot across a lake.
Signal wavers at 50-70% then drops sometimes to 0%, continuously. Effects 55 more. Moving the antenna around looking for sweet spot, I get the above or nothing.

area code 54982

multipath? Consider a 91XG for Fox 55 (and PBS 24) and a Winegard YA-1713 for channels 7 and 9. You will have better gain on VHF with the YA-1713 and hopefully you will have a narrower bandwidth with the 91XG. Silver Lake? I have a picture I took of the lake in December when it was frozen but snow free...right at sunrise.

You could be getting interference from another channel 31 for Fox 55. I see co-channel interference on your TV Fool plot, plus, there are adjacent channels 30 and 32 that are relatively strong in your area, so perhaps some adjacent channel problems also.

If I could get to my 91XG, I could help you out to see if it would work, but it is at the top of my tower on a 10' mast. I am not removing it anytime soon!

The CM antenna has high gain, but I know for a fact that it drops out at my location while the 91XG is rock solid. I am behind a hill and I had multipath with the 4228 while I have none with the 91XG. I lost a dB or so of gain on lower 20's UHF stations, but I completely eliminated my multipath, giving me a cleaner and better overall signal.

Bill

Before purchasing another antenna, try widening the reflector on your existing DB4 to 32"-36". As your antenna is protected in your attic, aluminum foil would work for the experiment. Four stations in El Lay reverted to their VHF-hi assignments, and I've widened reflectors on half-a-dozen 4-bay antennas to provide enough additional VHF-hi gain to make them usable.

Here's a link containing photos: http://www.avsforum.com/avs-vb/showpost.php?p=16638268&postcount=4934
For extension with rods, what type of materials did you use or would suggest for use as the extended rods and for mounting them?

TIA.

when you say "awash" you mean too much signal? i can get the UHF channels with ease, but the high VHF ones have been a battle since June 12 when ABC, CW and PBS went back to VHF land.

btw, the terrain profile makes you think you can spot the ESB.... i assure you that it's impossible even with a binocular because the hill in in the way. the TVFool info is wrong.

It's not that the TVfool info is "wrong" - your attention is directed at the note that says that the vertical axis is exagerated for visual clarity.

If you want something more precise, try Delorme has a software package for accuate terrain cross-section views. I forget the actual name of it off-hand, but a local guy was using it to screen potential customer's locations for a WiMAX application.

I hate to sound stupid, but has anyone suggested you try a regular old non-amplified rabbit ears? It may be your Terk is just lousy on VHF.

the HDTVa has rabit ears. i keep them open at about 150 degrees and stretched about 18" inches each.

i'm open to suggestions for a better indoor high VHF antenna.... i'm considering 2 models: "Winegard HD-1080" and the "RCA ANT751". i'm not sure if i can find a good spot for them inside a tight NYC apartment, but i could try. i can not get anything bigger.

With signals that strong you shouldn't need an amplifier, and it's generally better to not use an amp if you don't need to - avoids the whole intermod distortion/overload issue.

you guys have convinced me that -20db to -30db is a lot. however, i'm also convinced that TVFool is not showing accurate data. it might be right for the UHF channels, but LOTS of people on the NYC thread have complained about the VHF channels. so the high VHF figures on TVFool must be wrong.

the amp on the HDTVa can be turned OFF through a switch on the amp itself (the amp is a seperate piece and it can even be removed from the setup altogether). i've tried the HDTVa with the amp ON and OFF....on VHF and UHF. here is the results:

when it's ON, it improves the UHF channels slightly (90% -> 100%). it has never caused trouble any on the UHF band. i actually dont need the amp to watch UHF. like i said before, UHF is a not an issue at all in my apartment.

my problem is the high VHF channels. when the HDTVa's amp is ON, both RF-7 and RF-13 improve substantially (0 -> 40%)! that's why i'm inclined to believe that a stronger amp could help me more on the high VHF band. again, UHF has never been an issue here.

any suggestions for an indoor antenna with better high VHF performance? i'm gonna try to build a 1-bay high VHF bowtie today.

It's not that the TVfool info is "wrong" - your attention is directed at the note that says that the vertical axis is exagerated for visual clarity.

i can better understand the LOS issue now. according to holl_ands, visual LOS is different from radio LOS. that explains the confusion. the terrain image on TVFool doest mean much to me as i can go outside and see that there's a high hill between me and the ESB.

but again, i understand now that the term "LOS" is to be used loosely.

FYI: L.A. area "GCG Communicator" reported many Hi-VHF reception problems (Ch11/13) were solved by collapsing Rabbit Ears to about 14-inches (each)...

i've tried every angle and length possible in my HDTVa's dipoles. what i found is that 18in-length per dipole and an angle of about 150-deg work best. btw, i did try am angle of 180-deg....it gives me nothing.

Here are Rabbit Ear lengths (tip-to-tip when completely horizontal):
http://www.kyes.com/antenna/rabbitear.html

LOTS of good links in your post. i'm gonna check them all out. thanks a lot!

Surely you know an "HDTV Ready" antenna should have low VSWR, something typical Rabbit Ears are hopelessly impossible providing unless you have the skills to tweak every time you change channels.

is a bowtie or a big loop better in that respect?

Of course the best advice right now is to sit tight and wait a couple weeks for the VHF transmitters to sort out their Analog to DTV upgrades...it isn't a simple switch...

i got my 3 antennas (TV55, HDTVa, UFO) monday. if i want my money back, i cant take too long to return them. i'll wait a few more days but if i wait a month.

thanks for all the info.

Id get rid of that TV-55. You can aim it like a bazooka for UHF.

Try the CM 7777 with your HDTVa (-a) it wont hurt anything....or maybe a Winegard AP 8800 (http://www.solidsignal.com/prod_display.asp?main_cat=3&CAT=&PROD=AP8800)which has higher gain on VHF than UHF. You may be getting multi path problems with your VHF dipoles that are solved by the tighter beamwidth of the UHF elements on your HDTVa. (Especially if the RS UFO isnt working well for you as it has a wider beamwidth on UHF than the HDTVa)

Chart off amplifiers offered by SolidSignal. (http://www.solidsignal.com/antennas/preamplifiers.asp)

I wonder if VHF just isn't penetrating your building. I've heard that strong UHF can flood in through a window much better than VHF can.

How feasible would it be to test your antenna outside side for a few minutes? Can you get it to a spot where it'd have a relatively unobstructed view of the hill between you and the broadcast tower?

FWIW: for short cable runs, a stronger amp won't help. To improve reception, what you want is a cleaner amp (with a lower noise figure). I don't know anything about the a Terk - don't know if has a good low-noise amp. Personally, when I want amplification, I'd much prefer to couple an un-amplified antenna with a known high quality low-noise pre-amp, like the CM 7777 or the AP 8700. I've tried the amplified antenna thing, and I've always been disappointed - been unlucky enough to always buy bad ones, I guess.

I wonder if VHF just isn't penetrating your building. I've heard that strong UHF can flood in through a window much better than VHF can.

i dont know the material of which the building is made. i can tell you it has terrible acoustic insulation. i can hear people whispering in the courtyard an TVs in other apartments. pain in the neck! :mad:

How feasible would it be to test your antenna outside side for a few minutes? Can you get it to a spot where it'd have a relatively unobstructed view of the hill between you and the broadcast tower?my window faces the opposite direction....

I don't know anything about the a Terk - don't know if has a good low-noise amp.having the amp ON improves high VHF from 0->40% for both UFO and HDTVa. amps cant be so evil. :)

When you've turned off the amp, did it remain in the signal path? Is the amp built in to the antenna, or wired such that it has to stay connected? A powered-off amp often acts like an attenuator, blocking weak signals.

If you already removed it from the signal path, then don't mind me. Just trying to suggest things to try - to help diagnose what's going on.

Concrete, brick, stucco, metal siding, aluminumized vapor barriers(this one is hard to assess), terracotta roof tiles, all bad for RF signals.

Perhaps that wasn't clear.

If the amp blocks the signal when off, and hurts the signal when on (really noisy or overloading) - then removing it from the signal path completely might actually give you better reception.

More re VHF problems in several major cities, incl. NYC, Chicago, Philly, Houston and L.A.:
http://www.tvtechnology.com/article/82646
http://www.tvtechnology.com/article/82640

Good news: Ch4 in New Orleans has such a clear channel, it can be picked up in Toronto, Canada:
http://www.tvtechnology.com/article/82514

When you've turned off the amp, did it remain in the signal path? Is the amp built in to the antenna, or wired such that it has to stay connected? A powered-off amp often acts like an attenuator, blocking weak signals.

the HDTVa's amp is a separate piece that can be kept out of the equation completely. however, when testing, i limited myself to using the amps ON/OFF switch. i'll try this antenna again later without the amp.

thanks for the heads-up.

@nordl: If you want to try a combo VHF-Hi/UHF antenna, you can try the RCA ANT751. Its not that big and if you are in 2nd floor or higher apartement, you can probably lay it in the floor or probably conceal it under the sofa or bed or worst case mount it to a floor lamp/speaker stand. Also its available in local Wal*mart so you can easily return it too. Atleast its available in Central Jersey. Only problem with this antenna is that UHF gain is nothing to talk about so you may need an amplifier (probably you don't need it because you are in Manhattan.. close to transmitter). I think CM7777 will be an overkill for you. I am also at a similar situation like you where I am not getting no VHF-Hi using my eagle-aspen UHF. I haven't done any of the VHF-Hi mod yet. As of me, I received my CM-3030 today with the CM-3038 preamp. Have to check out how it works at 33 miles from NYC.

I need recs for this situation. Friend of mines, place in the mountains of North Carolina, near Mt. Mitchell.

Old Mill house is metal sheathed.

http://www.tvfool.com/?option=com_wrapper&Itemid=29&q=id%3d7f1480d77d8eb6


Please help!

I need recs for this situation.

Did you try more height? The CBS station won't work at 15'. Most of the others are marginal.

When stacking a VHF antenna with a UHF antenna on the same mast, should the VHF antenna be on top or below or does it matter?

When stacking a VHF antenna with a UHF antenna on the same mast, should the VHF antenna be on top or below or does it matter?

I'd look at the weakest station that you want to receive. Next, using tvfool, try swapping the two antennas. I'd install the antennas in whichever position gave you the most margin on the weakest station.

More re VHF problems in several major cities, incl. NYC, Chicago, Philly, Houston and L.A.:
KYW NewsRadio reporter John Ostapkovich talked to RF expert Oded Bendov about VHF DTV reception problems. In his article Transmitter Expert Not Surprised by DTV Transition Woes, “The FCC has done very poor engineering and assigned Channel six and other channels in the VHF much lower power than they should have,” Bendov said. “For example, in the case of Channel six, they probably need as much as 15 times more power in the transmitter than they have now."

Bendov said that finding a UHF channel for channel 6 (WPVI-TV in Philadelphia) and “others in this pickle” might be the only solution.

Yep, they should have realized this long ago. Even with a CM1221, the signal meter on WPVI-TV for me is jumping up and down all over the place.

Dombrowksi says WPVI-TV people are meeting with the FCC to try to figure out what's wrong (is it a transmitter problem, a rabbit-ears problem, or a converter box problem?) and solve it as soon as possible.
I cant believe they dont/didnt realize that transmitting with only 7.56 KW may present a problem, heh. (Hmmm, their Action News van may actually carry that much transmit power, at least their pre-satellite vans)

Even with a CM1221, the signal meter on WPVI-TV for me is jumping up and down all over the place.

What does it look like today?

WPVI may have rasied power last night.

...I cant believe they dont/didnt realize that transmitting with only 7.56 KW may present a problem...

The reduction from 74.1 KW to 7.56 KW is no greater than the power reduction ratios of most other VHF transmitters. Nevertheless, there are two factors that make the channel 6 situation difficult to deal with.

1) Since channel 6 is VHF lowband, its wavelength is such that you need a dipole nearly seven feet across to receive it efficiently, but it is very impractical to use an indoor antenna that wide,

2) There are lots of FM radio stations at the low end of the dial that will interfere with it when one is closer to the radio tower than to the TV tower, but which any channel 6 TV signal would wipe off the radio dial if they were given more power.

Stations that settled for, or were stuck with, channel 6 knew what they were getting into, but it was determined for their situation that there was no better alternative available.

@nordl: If you want to try a combo VHF-Hi/UHF antenna, you can try the RCA ANT751. Its not that big and if you are in 2nd floor or higher apartement, you can probably lay it in the floor or probably conceal it under the sofa or bed or worst case mount it to a floor lamp/speaker stand. Also its available in local Wal*mart so you can easily return it too. Atleast its available in Central Jersey. Only problem with this antenna is that UHF gain is nothing to talk about so you may need an amplifier (probably you don't need it because you are in Manhattan.. close to transmitter). I think CM7777 will be an overkill for you. I am also at a similar situation like you where I am not getting no VHF-Hi using my eagle-aspen UHF. I haven't done any of the VHF-Hi mod yet. As of me, I received my CM-3030 today with the CM-3038 preamp. Have to check out how it works at 33 miles from NYC.
As of now, I have mounted the CM3010 with CM3038 indoor at the same place. I am getting all the channels now including all the VHF-Hi. However ABC at channel 7 is heavily pixellated and can't watch now. I am waiting for the flat RG-6 coax coupler, after which I will relocate the antennna in the balcony. Here is the dirty setup:
http://img36.imageshack.us/img36/2151/stealthantenna005.th.jpg (http://img36.imageshack.us/i/stealthantenna005.jpg/)

You're a bit far for the C4's limited H-VHF capability. That usually maxes out around 40-50 miles with good LOS and adequate signal power. Since you're missing LOS and are at around 55-60 miles, you will definitely need a dedicated H-VHF antenna.

The C5 might be enough, certainly worth a try, especially since it's very compact but of similar performance to a 5-element Yagi. A little birdie told me a small quantity may be shipped by a really big birdie in the next day or so, maybe those will be made available for purchase.

BTW, how is the C4 doing with the UHF signals coming from Mt Wilson to your location?

Ordered the C5 on Thursday. Set to be delivered this Thursday. I'll let you guys know how it works. I know it will be tough to get those channels (7-13) but if the C5 works like it is supposed to, I should get them.

2) There are lots of FM radio stations at the low end of the dial that will interfere with it when one is closer to the radio tower than to the TV tower, but which any channel 6 TV signal would wipe off the radio dial if they were given more power.

Plus the electrical noise that channel 6 especially likes to pick up. But wouldnt you think digital channel 6 with 74.1 KW of power would be less bad than analog channel 6 with 74.1 KW of power for the FM stations ?
Sigh, and to make matters worse for me, there are 2 other channel 6's pointed in the same general direction. I can forsee a tropo condition wiping out WPVI.

What does it look like today?

WPVI may have rasied power last night.
Its pouring today, so that wouldnt be a real fair comparison. Its still jumping a lot though.

As of now, I have mounted the CM3010 with CM3038 indoor at the same place. I am getting all the channels now including all the VHF-Hi. However ABC at channel 7 is heavily pixellated

"dirty setup"? you should see the mess i've made here so far. i'll keep the CM3010 Stealthtenna on my radar as well. looks like a manageable size. how far from ESB are you?

regarding my late night post.... i wasnt receiving PBS at all at that point, but i can watch it now on the amplified UFO. i still think they were off air then, since the weather was no better at those hours than it is now. i hope they are working on improving their signal....

http://img29.imageshack.us/img29/1528/pbsrf13.jpg


using instructions i found on a PDF uploaded to AVS, i made a "1-bay" bowtie antenna yesterday. the PDF was for a "2-bay VHF-Hi", but i didnt wanna get in too much trouble with assembly, so i made it "1-bay". i got no VHF-Hi with it (maybe due to the cut in the number of bays).

i kept twisting the wire to diff shapes and sizes and i got better results after a while: 40% signal on Ch 13.1 without any amp (the HDTVa and UFO also give me 40%, but only if amp is ON). i'll work on my "design" a bit more later today if weather improves.

Hopefully the 1-Bay or 2-Bay antennas you refer to were sized for the Hi-VHF band???
The UHF models will be much worse than Rabbit Ears....Which design????
Did it have a reflector screen to attenuate multipath signals coming from the "back"???

If you want to try a simple, easily hidden, DIY Hi-VHF antenna that is a step up from
Rabbit Ears, you can start with a Folded Dipole:
www.imageevent.com/holl_ands/yagis
Perhaps you have some metal (or aluminum foil, can also be flat&thin) laying
around that can be RECYCLED....half-inch size will adequately cover entire Hi-VHF Band.
But it has bi-directional response and would benefit if a simple Reflector rod is added:
http://www.wfu.edu/~matthews/misc/dipole.html
Could also use some sort of metal (e.g. wire mesh or Al Foil) reflector plate....like a 2-Bay.

For about $10, I just built one from 1/2-inch Type M Copper Tubing to use as my
"standard" 0 dBd gain antenna for on-air comparison tests. [27.5 x 2.0-in center-to-center]
[Still needs Rosin Core Solder (No plumber's Flux) for connections...and brass nuts.]
[Hmm, should polish & varnish....pretty, pretty....the wife isn't happy with it in the L.R.]

Those 1-Bay and 2-Bay antennas are even worse than Rabbit Ears for VHF.
Even mclapp's M4 SuperSized 4-Bay is limited to just a few contiguous Hi-VHF channels:
www.imageevent.com/holl_ands/4bays (http://www.imageevent.com/holl_ands/4bays)

link's broken.

Typo...delete the "s":
http://www.imageevent.com/holl_ands/4bay

I revised the post...I just wanted to make double sure you were using a Hi-VHF rather than a UHF design.
My (no reflector) 4bay webpage is for UHF, where some just happen to work (a little) on Hi-VHF.
And once you add a reflector, it's gonna kill the Hi-VHF capability....unless resized for Hi-VHF.

Ordered the C5 on Thursday. Set to be delivered this Thursday. I'll let you guys know how it works. I know it will be tough to get those channels (7-13) but if the C5 works like it is supposed to, I should get them.

A heads up regarding the UVSJ (diplexer) that is included with the C5:

The plastic case will accommodate either a compression- or crimp-fit F-connector but will not allow the lid to close if you're using a cable with a longer-length factory molded connector or an RG11 compression fitting.

Plan accordingly.


About two weeks ago I was able to get my hands one of the first pre-production C5 antennas.

With an antenna height of only about 12 feet and a good test location (empty lot at NEQ of I-44 at Gray Summit, MO at around 8 AM), I was able to see a near-perfect 8VSB waveform on my Sencore 1474 of KRCG-13 (VHF-12 out of Jefferson City) of more than adequate amplitude to be useful. Distance of about 70 miles with little intervening noise generators. Measured value was approximately -30 dBmV with a C/N ratio of 9.5. Very easily usable with a decent low noise preamp or with some more height.

FCC-predicted signal level was -94 dBm, TV fool for the same spot was -98.1 dBm.

If you want to try a simple, easily hidden, DIY Hi-VHF antenna that is a step up from
Rabbit Ears, you can start with a Folded Dipole:
www.imageevent.com/holl_ands/yagis (http://www.imageevent.com/holl_ands/yagis)

thanks for the links. i checked the "folded dipole" info but it looks a bit too complicated for me (a layman). the other thing is, i dont have the tools to build something that requires such a degree of precision (dimensions and distances depend heavily on wavelength).... :(

the link below seems to be the less complicated one.
http://www.wfu.edu/~matthews/misc/dipole.html (http://www.wfu.edu/%7Ematthews/misc/dipole.html)
i might give it a try during the week.

has anyone here tried the Winegard HD-1080? based on the number of times i've asked and the zero feedback i've gotten, i guess that's the most obscure antenna on Winegard's catalog. :D

The 1080 is "okay" for UHF. On high vhf, it has large negative gains especially for ch9 and below. There are much better choices if you need high vhf reception.

The 1080 is "okay" for UHF. On high vhf, it has large negative gains especially for ch9 and below. There are much better choices if you need high vhf reception.

yes, i need Hi-VHF. preferably, an antenna that can do UHF too, but it doesnt have to be a great UHF antenna because only Hi-VHF is problematic in my area. UHF comes very easy. how would you compare the HD-1080 to the ones below?

RCA ANT751
CM3010 Stealthtenna

The Winegard HD 1080 isnt particularly good on VHF Hi....certainly no better than Rabbit Ears and probably worse.

still regarding folded dipoles, is the Terk TV55 (bazooka) a folded dipole? it didnt work for VHF or UHF in my apartment.

Helical Coil, (Helix)

Has anyone seen any specs on either the EZ-HD or the RCA ANT751???
Websites I've checked omit these important little details....

Despite several distractions, I'm still working on the NEC model.
From what I've seen so far, VHF RAW Gain for Ch7 is about 5.5 dB,
rising to 7.5 dB in mid-band and falling some across Ch12-13.

Front-to-Back Ratio is 10+ dB on Ch7, rising to 15+ dB mid-band and
then falling off across Ch12-13 (due to falling forward RAW Gain).

Based on difficulties with YA-1713 model, I expected SWR to be
difficult to model accurately....EZ-HD is no different....maybe it's
a 300-ohm antenna, but I'm seeing much less at VHF freqs....
[Still gotta add the stubs to run UHF curves...]

People should pay close attention to how these "twins" perform on Ch12 & 13....
I hope it's because of a NEC modeling shortcoming.....like the YA-1713 model,
which has a very similar Log-Yagi VHF design....

Has anyone seen any specs on either the EZ-HD or the RCA ANT751???

here's some info (http://www.avsforum.com/avs-vb/showthread.php?p=14719627#post14719627) gathered from another post:

Sent an email to the site selling the ez-hd antenna and asked about vhf high gain. He replied "The EZ-HD has an average of 7.5 dB gain on VHF. To combine a VHF and UHF use a VHF/UHF signal coupler. This will result in much less signal loss." Does that sound about right? solidsignal has the AntennaCraft Y5-7-13 specs at "Gain VHF: 6.9 dB". Also What's the difference between UVSJ diplexer and a VHF/UHF signal coupler?

yes, i need Hi-VHF. preferably, an antenna that can do UHF too, but it doesnt have to be a great UHF antenna because only Hi-VHF is problematic in my area. UHF comes very easy. how would you compare the HD-1080 to the ones below?

RCA ANT751
CM3010 Stealthtenna

I have personal experience with the EZ HD, similar to ANT751. It works very well for high vhf in my area (ch 8, 9, and 10). It should be noted that we have strong vhf signals (NM's from tvfool were between 50 and 55 dB). The EZ HD or Ant751 would **easily** beat the HD-1080 for high vhf.

Good luck!

Ive got the box and whatever manual or spec sheet manual came with it at home, Ill see if there is any information.

Ive been going with the Winegard 7000R specs as comparable. Here you can see the slight drop off at Channel 13 and also a lower Channel 14, gain spec rising up through the upper UHF television band. The UHF section is nearly identical so I think those specs are probably comparable.....its likely that the RCA ANT751 and EZ HD have slightly better VHF Hi performance....as your modeling would suggest, hollands.

http://www.winegarddirect.com/viewitem~d~Winegard-HD7000R-VHFUHFFM-DTV-TV-Antenna-(HD7000R)~p~HD-7000R.htm

The EZ HD or Ant751 would **easily** beat the HD-1080 for high vhf.

does it work well for UHF too?
did you place indoors or outdoors? i can only place antennas indoors.

does it work well for UHF too?
did you place indoors or outdoors? i can only place antennas indoors.

Its slightly inferior to the Silver Sensor unamped on UHF, especially on the extreme low end of the UHF television band.

It matches the performance of the "Silver Sensor on UHF" in the VHF Hi band, about 6db gain.

It might be the best solution for you.

The StealthTenna is an interesting choice.....and more aesthetically pleasing. Mount it on the ceiling and call it sculpture for you snooty NY friends. :)

The StealthTenna is an interesting choice.....and more aesthetically pleasing. Mount it on the ceiling and call it sculpture for you snooty NY friends. :)

i would if i had any drilling skills whatsoever! :p
i'm torn between the ANT751 and the CM3010....