Advice for NH

[dbk]

I'm looking into dropping Comcast and started doing some research into OTA.

I would like some advice on a setup that would allow me to receive the channels in the green and yellow sections. I really only care about the Boston channels though the more the merrier. http://www.tvfool.com/?option=com_wrapper&Itemid=29&q=id%3d9e7425c4fb0710

I will only be feeding one TV (TIVO) and don't really have a preferred installation point (roof, attic, whatever). I used a height of 25 ft for the report as that is the approximate height of my attic. Given that some installation points will be easier than others, I'd be curious as to what I could expect from the different ones.

Cheers!

[GroundUrMast]

I'd use a two antenna system.

Facing south, a 4-bay panel antenna for UHF reception, an Antennas Direct DB-4 for example. The second, an Antennacraft Y5713 pointing at about 50° which will offer reception of WMUR and WENH.

The two antennas can combine into one coax with a UVSJ (http://www.solidsignal.com/pview.asp?p=UVSJ&d=Pico-Macom-UVSJ-UHF-VHF-Band-Separator%2FCombiner-for-Antenna-%28UVSJ%29).

Given only one tuner, I don't think any amplifier will be needed... in fact, the possibility of overloading recommends you avoid an amplifier.

I would strongly favor outdoor mounting of the UHF antenna. Attic mounting of the high-VHF would likely work unless your roof accumulates significant snow load.

[dbk]

Thank you for the response.

I was wondering why you suggested a 4 panel vs 8. Reviewing the different specs it looks like the Boston stations are at the upper limit distance wise for a 4 panel. I always like to learn so I was wondering what the discriminators were in your dicision.

[GroundUrMast]

My recommendation assumes you will mount your UHF antenna outside, free of obstructions, at about 25 feet above ground and that your TVFR is reasonably accurate. The long list of LOS (line of sight) signals is very favorable. The 8-bay will offer more gain at the expense of narrowing of the forward beam. Compared to a 4-bay, the 8-bay will be less able to receive stations to the left or right of it's aim point.

Mileage estimates offered by reputable antenna manufactures are helpful, absent any other design assistance but gain referenced to a standard is far more accurate and useful. Any of the 4-bay panel antennas should offer at least 12 dBi gain. The DB-4 specification is 13.7 dBi, which is presumably a peak gain figure at it's best frequency. TV Fool generally uses the dBd standard which is just as valid, the conversion is easy, just subtract 2.15 dB from the dBi figure to convert to dBd. Per your TVFR, predicted noise margins for all of the receivable UHF signals south of you are +16 dB or higher. When you add the gain of the 4-bay to the NM you have ample fade margin even for the weakest signals.

For example WHDH is predicted to arrive at your location with a noise margin of 22.5 dB. If your antenna has 10 dBd of gain, the net NM will be 22.5 + 10 = 32.5 dB which is quite good. You should expect to have reliable reception with stable NM figures of +10 dB. (Stable NM will require that interference from multipath, noise sources and other transmitters be non-existent or supressed.)

Weak signals starting with those in the red section of your TVFR would require much more effort due to the low signal levels and the presence of adjacent and co-channel interference.

[dbk]

Thank you for the advice.

I installed the antennas you suggested on my roof today and couldn't be happier.

[GroundUrMast]

The POP! you just heard was my swollen head exploding :p

Glad to hear of your success.