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Old 20-Jan-2010, 5:10 PM   #1
h20rat
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Antenna purchase

Hello all,

Need some help making a determination on an antenna purchase for OTA only set-up. I have a USTEC board with a CATV amplifier already setup in the house that will keep the signal strength up to each tv. (I have 4 tv's -two are HDTV).

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http://www.tvfool.com/?option=com_wr...c5729c97f4aa22

Thanks!
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Old 20-Jan-2010, 11:39 PM   #2
mtownsend
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Hello and welcome!

Your situation seems to be pretty straightforward. You gets lots of channels from just one direction and their signal strengths are good. For this situation, I would recommend a Winegard HD7695P on the roof pointed at a compass heading of 88 degrees.

WVEN and WOPX are not in the same cluster as everyone else (about 40 degrees off-aim), but since they are your strongest channels, there's a good chance that you'll still pick them up even if your antenna is not pointed directly at them.



Also, just FYI, CATV amplifiers sometimes include a "return path" in their design. That means that they allow RF energy to go backward through the amp for "upstream" signaling like cable modems. For OTA applications, people usually don't use these kinds of amps because that return path signal ends up going back to the antenna and radiating out into the environment. I don't think there's much chance of this causing any problems, but it's just something to be aware of.

Generally speaking, CATV amps also have worse Noise Figure specifications than a good OTA pre-amp. That is because they are expecting very strong signals at their input and don't need a very good Noise Figure specification to do their job. In OTA situations, especially if some of the channels are marginal, it's very important to find an amp with a low Noise Figure rating (usually under 3 dB).

In your situation, the signals are probably strong enough to work just fine. However, if you do discover that some of the channels are dropping out, you might consider swapping the CATV amp with one better suited to OTA applications.
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Old 21-Jan-2010, 2:05 PM   #3
h20rat
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Thanks for the quick response!

I am thinking about an attic installation since we do get alot of high winds and of course, lightning. Do you think the HD7695P and a CM-7777 would be good or should I consider going up a level?

I will take your advice and by-pass the CATV amp.

Thanks.
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Old 21-Jan-2010, 3:07 PM   #4
h20rat
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Q: Is the CM-7777 more suited for a single TV configuration? If so, since I have multiple TV' s would I be better served with something like a Winegard AP-8275? Or do you recommend something else. My goal is to get a good configuration with the least possible drop-outs, pixelization etc., since this will be our primary access (no more cable fees..yay!) Thanks for your help.
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Old 21-Jan-2010, 6:40 PM   #5
mtownsend
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Quote:
Originally Posted by h20rat View Post
I am thinking about an attic installation since we do get alot of high winds and of course, lightning. Do you think the HD7695P and a CM-7777 would be good or should I consider going up a level?
An attic install will probably work. There are a greater number of variables since every attic is different. The construction type, presence of metallic objects (e.g., foil-backed insulation, ducts, metal bracing, wire mesh/stucco, etc.), and roofing material can all impact performance, so the degree of signal loss/degradation is unknown until you try it.

Most attics have only mild losses, so there's a good chance that going up one antenna size (to an HD7696P) is enough to make up for the difference in signal strength. My guess is that the HD7696P + 7777 will work great. The HD7695P might also work, but I'd feel more comfortable with the extra margin for error that the HD7696P offers.
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Old 21-Jan-2010, 6:46 PM   #6
mtownsend
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Quote:
Originally Posted by h20rat View Post
Q: Is the CM-7777 more suited for a single TV configuration?
No. The CM 7777 is a good pre-amp with high gain. It's output levels should be strong enough to drive multiple TV with no problem.



Quote:
would I be better served with something like a Winegard AP-8275?
The Winegard 8275 performance is in the same ballpark as the Channel Master 7777, so either one would work.



Quote:
My goal is to get a good configuration with the least possible drop-outs, pixelization etc., since this will be our primary access (no more cable fees..yay!)
Then, by all means, go up one antenna size for the extra reliability.
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