I have an attic mounted discone antenna that I have used to feed multiple Uniden scanners. I noticed that my 996T and 780XLT could pick up aircraft frequencies that my 996XT, 536HP, and SDS200 could not. I eventually discovered the problem was my local channel 13 television station. I made a 212 mHz open coax stub (8" of RG59) attached to a tee where the antenna connects to an active coupler. This reduces the TV signal by about 20 dB. Now any of my scanners will work perfectly on air band. My test signal is a 2 watt ASOS transmitter about 5 miles away, which is not audible when I disconnect the stub. I suspect the TV signal would also affect a handheld in a similar manner. My 396T is much better than my SDS100 on air band at my location.