Total posts : 45366
I have established that it is not the audio source. I can induce a different kind of hum when I turn up the gain or compression too high, but get relative quiet when operated at proper levels. As a precaution I have already installed a RS ground loop eliminator in the audio line. My antenna wires go through a plastic cable pass-through tube in the wall to the outside. The white (hot) wire then goes vertical up the side of the house made of painted cinder block. Once outside the black (ground) wire is clamped to an 8 foot commercial grade ground stake. In the process of passing through the wall the antenna wires do pass within a 1/2 foot of a wall AC outlet in which the transmitter power supply is plugged in.
I don’t have any problems listening to other AM stations in the house. Just mine. I have noticed that the hum is much worst on some frequencies than others. It was unlistenable at 1360, for example. I normally run it at 1620 and the hum there is still present, just not quite as loud. Could the RF be getting into my house wiring somehow and causing this problem? If I take a battery powered radio into the yard it is pretty clean. I can still move the radio orientation around and get some hum, but not like in the house. Same story in my car. The biggest problem is with the radios in my house that are plugged in. As a matter of fact when listening on a plugged in radio it seems that the further from the transmitter that you get, the worse the hum is. The exception is very close to the transmitter. I have the RS version of the SuperRadio plugged into the same outlet as the transmitter power supply and have no problem. That radio is about 4 feet from the SSTran. 30 feet away in my living room on a Sangean HD receiver every AM station is clean except mine. 50 feet away in the master bedroom the buzz is the worst on both the clock radio and my old RS Long Range AM portable that they made in the early 1980s. Even a battery powered radio will hum in the house if it is not positioned into the perfect orientation.
The fact that I can get a reasonably clean signal on a battery powered radio that is properly oriented leads me to believe that the transmitter is not suffering from a bad component. The whole situation reeks of RF somehow getting into the house wiring or the plumbing and with the over the air signal strength weakening with distance from the transmitter, the hum takes over. But since I am not an engineer, I have no idea what to check or look at to prove this theory or how to combat it.
I have been fighting this battle for weeks and am just about ready to give up. Again, any help from the engineers and other smart people on this board would be most appreciated.