I recently moved to an apartment and I've been experimenting with different antennas and configurations in order to achieve the best OTA reception. I've been comparing Philips Indoor/Outdoor MANT950 to a Philips Silver Sensor. The Silver Sensor picks up every station stronger than the MANT950 - except one. Channel 11-1 (NBC, frequency assignment 10) gives me a signal strength of approx 75 using the MANT950, and absolutely no signal at all using the Silver Sensor. Why would this be?