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Old 3-May-2012, 11:11 PM   #12
GroundUrMast
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Join Date: Oct 2010
Location: Greater Seattle Area
Posts: 4,773
You may have already read the TV Signal Analysis FAQ . The explanation of NM is particularly important. At the most basic level, NM + Antenna Gain needs to equal a positive number for a tuner to have a chance of locking onto a digital signal. A net NM of +10 dB or greater is needed to allow for signal fade, additional noise and interference. Engineering for a net NM of over 15 dB is not overkill in my opinion. When faced with strong local signals, even greater efforts may be needed to prevent interference to the weaker signals. Note that Antenna Gain and Amplifier Gain are not the same and are not interchangeable in the above calculation.

An extremely large parabolic antenna such as the Wade PB-82-BB is about 150 lbs and claims gain of 21 to 25 dBi. (In a big storm it can put over 1000 lbs of force on the supporting tower.) The largest consumer grade antennas top out at about 16 or 17 dBi. The point being, signals with predicted NM values below -10 dB have little hope of reliable reception with any antenna.

Another point; I have occasionally seen a few new members recommend an antenna based on the naive notion that "if it worked for me, it should work for everyone" or "this is my favorite". That does not describe the work of the regular contributors here. The recommendations made by the regular contributors here at TV Fool are based on an understanding of the physics and the math that goes with the theory.

@Electron's suggestions deserve your consideration. As a moderator, I want to thank you for resetting the tone of your thread.
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Last edited by GroundUrMast; 3-May-2012 at 11:30 PM. Reason: mutual respect
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