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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.
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If the well is dry and you don't see rain on the horizon, you'll need to dig the hole deeper. (If the antenna can't get the job done, an amp won't fix it.)
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Last edited by GroundUrMast; 1-Sep-2011 at 4:26 PM.
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