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Old 20-Dec-2011, 2:54 PM   #2
Tower Guy
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Join Date: Dec 2009
Location: Delmar, NY
Posts: 1,236
Quote:
Originally Posted by GroundUrMast View Post
In particular, what is a practical minimum NM goal for reliable reception in the low-VHF band?
That's not an easy question to answer. The noise on channel 2 is 4-6 db worse than channel 6. The take-off angle of a receive antenna is closer to the horizon on channel 6 than channel 2. During the Sporadic E season channel 2 will get distant co-channel far more often than channel 6. Yet channel 6 can suffer from FM interference.

The FCC planning factor for low band VHF allows 4 db extra noise, but that is not considered on TVfool. Coverage to an indoor antenna is far worse on VHF than UHF.

Next the available low-band VHF receive antennas have less gain than UHF antennas. A slight down-slope in front of a low band VHF antenna can help significantly.

Bottom line, on channel 6 I look for a NM of 10 db or more and then the antenna must have at least 6 db gain and the antenna location must be favorable and the noise level must be at or below normal. If channel 2, I'd be trying for 18 db NM or more.

Rarely does a preamp help low band VHF reception.
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