I am trying to receive an am signal well below ground level in a metal server room, there is a coax feed up to the roof which I used and attached the standard wire loop that was supplied with the tuner, however when I attempted to tune into some stations I could only pick up a couple of local stations and wasn't able to receive the ones I was hoping for. when I dialed in the desired frequencies, all I was receiving was a tone, the tone changed in frequency/pitch depending on the tuners frequency. To check that I could receive the stations I took the tuner to the roof and attached the antenna directly and sure enough I could pick up the desired stations. My thoughts are that the coax is affecting the signal in some way, perhaps picking up electrical noise? any advise would be appreciated.