Anyone reading this thread should not conclude that antenna system grounding is going to cost them signal strength.
While I fully agree that the mast and coax shield should be grounded, I recommend doing so for reasons of general electrical safety. Correct grounding practice does not reduce the antenna system signal output to the TV unless additional coax is used to reach the grounding block, and then the effect is negligible unless a great deal of extra coax length is involved.
I agree completely, the signal levels are so strong that the other measures suggested thus far are appropriate;
1. No amplifier should be used in this system.
2. Re- aim and/or move the antenna.
3. An attenuator is indicated. (I doubt a variable design is needed, or worth the added expense. I would try 16 or 32 dB of fixed attenuation)
http://forum.tvfool.com/showthread.php?t=901
http://www.amazon.com/Steren-16dB-In...ref=pd_sim_e_6