Is my preamp too strong?

[l2pad]

Last night I set up the AP8700 and got a really nice boost in signal
22 went from 87% to 90%
14 went from 82% to 84%
13 went from 37% to 72%
32 went from 67% to 82%
43 went from 57% to 77% and
57 went from 52% to 75%
I congratulated myself and then the s#$% hit the fan. I lost everything above 22 and the signal strength of the remaining channels dropped in half. I’ve got close to a 100’ coax run from antenna to tv with no splitters. Is the AP8700 too strong? Anther thing I noticed is that without power going to the preamp the signal strength coming to the HDTV is less than half of the signal I get without the preamp in-line...

[TomV]

What is your location (zip code) so we can look up your potential signals using TVFool.

You cannot expect anything good when you remove power from the preamp and yet leave the preamp in the circuit. It does not just "pass through" the signal but will attenuate it and not predictably.

The preamp is most probably overloading your TV since you have some good signals at 14 and 22 already. The 17+ dB gain is overkill for your setup. The 100 foot cable, if RG6, is dropping about 7 dB at UHF channel 50, the highest channel that most stations broadcast at.