In December I purchased an outdoor OTA antenna. As the weather here in Oregon has been rain it has sat in the corner of the family room about 3ft from the floor on a stool. All the local HD OTA channels came in strong and we've had no problems with it. Only the OPB HD channel had a weak signal. This is connected to an HR20-700 Yesterday I mounted the antenna outside about 14ft higher than it was. It is pointed at 292 degrees, the same as before. The problem is the NBC channel signal is very inconsistent, from 100% to no signal and we get the 771 searching for signal message every couple of minutes. All the other channels the signal strength is improved and the OPB signal is twice what it was. I've tried rotating the antenna but if anything the signal gets worse on NBC. I'm at a loss as to why moving the antenna outside and elevating it should make one channel signal worse. There are trees nearby but the antenna is positioned such that they shouldn't effect it. Any idea what I might try to correct the problem. The antenna has an amplifier on it which came with it from Radio Shack and we are about 7.5 miles from the transmitter.