I need help or suggestions solving a receiver problem. I have tried 3 different receivers and all three experience the same problem. While listening to the received signal on two transceiver radios, and one receiver, suddenly the signal strength goes from 20 over S-9 signal to s-3 or 4. When I push the PTT key on the transceiver, the receiver comes back to life but soon afterwards fades back to reduced gain. On just the receiver, turning it off turning it back on restores that signal but soon it fades back to reduced signal. Signal loss is either due to antenna or coax but I'm not certain which. Has anyone ever experience this problem and what did you do to cured it?