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The Official AVS Antenna and Related Hardware Topic!

4M views 20K replies 2K participants last post by  Davenlr 
#1 ·

Please post your experiences with antennas, preamps, all related equipment, and installation experiences. Indoor & outdoor. To include mounting, cabling, connectors, rotors, etc.


- Be specific; brands, models, sources, prices, etc.


- What works, what doesn't, and why?


- Tricks of the trade, and unique solutions.


Thanks in advance for your participation. AVS is only as good as it's members, and our members are the best.


Moderators Note as of 2/15/2012: The "Antennas, rotators, boosters/preamps... for wide-band VHF/UHF" has been merged into this topic, which now covers not just antennas but preamps, rotors, antenna cable, mounting systems, termination, transformers, baluns, distribution amps, and all other OTA reception related equipment.


As always, set-top-boxes are covered in the Official AVS STB Topic, found 'stuck' at the top of the HDTV Technical Forum.
 
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#10,841 ·

Quote:
Originally Posted by kedirekin /forum/post/16683698


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!


Quote:
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....

Quote:
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.
 
#10,842 ·
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.
 
#10,843 ·
Concrete, brick, stucco, metal siding, aluminumized vapor barriers(this one is hard to assess), terracotta roof tiles, all bad for RF signals.
 
#10,845 ·
#10,846 ·

Quote:
Originally Posted by kedirekin /forum/post/16683923


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.
 
#10,847 ·
@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.
 
#10,848 ·
#10,851 ·

Quote:
Originally Posted by finlay648 /forum/post/16687598


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.
 
#10,852 ·

Quote:
More re VHF problems in several major cities, incl. NYC, Chicago, Philly, Houston and L.A.:
Quote:
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.

Quote:
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)
 
#10,854 ·

Quote:
Originally Posted by 300ohm /forum/post/16687964


...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.
 
#10,855 ·

Quote:
Originally Posted by kousikb /forum/post/16684895


@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:
 
#10,856 ·

Quote:
Originally Posted by ProjectSHO89 /forum/post/16642463


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.
 
#10,857 ·

Quote:
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.

Quote:
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.
 
#10,858 ·

Quote:
Originally Posted by kousikb /forum/post/16688137


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....





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.
 
#10,859 ·
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.]
 
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