AM Radio through AirTunes When Active

Question

Ok, I have seen more than a few posts about this, but not someone address the problem that I have seemed to deduce through careful testing, experimentation and general sluthiness.
So, I have been getting an interfering signal (AM Radio Stations 1120 and 1240 mixed together) mixed into my connected stereo when using the Airport Express to play music. I just updated my Firmware to v6.3, and that seemed to help, but only because it deactivates the audio port when you stop playing music. When I am not playing music, there is no sound. When I hit play in iTunes, the sounds begins when the port is activated, and then music plays over the top a few seconds later. After you stop the music, the signal continues, until the audio port is deactivated. The easiest way to hear the problem was to activate the line using AirFoil, which just keeps an open connection to the audio, and crank my stereo to max volume while plugging and unplugging things till I had no interference.
I have great audio cables, and have tested different cables, different speakers and a different stereo system all-together without complete success.
I noticed first that I continued getting a low buzz when I even unplugged the express from the wall. This led me to try the other cables, and in doing this I have figured that it is NOT the Express, it's my damned house and where I live apparently. When I unplugged the printer and ethernet jacks from the express, the AM sound, and the buzz both were gone. Even when the AE is plugged in, it works just fine when nothing else is plugged in. So my ethernet cord and printer were amplifying together to make the sound twice as bad. It was even ok to leave the USB cable plugged in, and just unplug my printer's power cord. Although it did not help to unplug my modem's power.
So, my theory is that my home's power cords are picking up this AM signal, and sending them through both the ethernet line, and the USB line to the Airport Express. Or the lines are picking them up on their own, but only when connected to the devices they come from (meaning I left the cables attached to the AE, and unplugged them from the printer/cable modem, and that also made the sounds go away).
So, sorry for this long post, buy my question is basically, can I get higher shielded ethernet cables and USB cables? Can I get better power cords for my printer? Or are these signals coming thru the lines, and thus a shielded cable isn't going to help at all?
And if that is the case, do audio signals traveling thru an active line screw with data that is being sent through those lines? Like slowing my internet connection or messing with things I am trying to print.
Thanks to anyone who can help, I'm going to see if I can talk to an Electrical Engineer about this too (since I am in school, and they are around), but anyone with some insight into this would be SWEET!
Thanks for taking the time to read this! HA!
PowerBook G4   Mac OS X (10.4.8)  

Answer 1

Somewhere, in these forums, my earlier posts about an issue I had with
my iMacG4 1.25 17" USB 2.0 computer was related in a way to your issue.
Mine would broadcast keyboard clicks, opening/closing windows, scrolling
and most desktop & application activities -- over an AM radio -- 30 ft away.
Finally, that and two other issues were finally resolved after 14 months of
taking my computer in cycles of 200 miles each, to the nearest authorized
repair facility; and leaving it there. I logged over 3,000 miles on my vehicle
on hauling my computer back and forth. Oh, it also would freeze up if I
had more than two internet-using applications open at the same time; but
only at odd time sequences. I figured out how to duplicate all that, and
after the end of my initial Apple warranty, I got two logic boards replaced.
There are a few issues remaining; and I have 10 months left on AppleCare.
Could be one of the things I learned about electricity and these odd
radio frequency things, is, to get and try some torroid magnet sets and
see if wrapping the speaker wires and other power wires around them
will help cancel the extra signals you are getting. This may need to be
done on the electrical supply wires to wi-fi base stations and others.
I had bought some magnets from a Radio Shack affiliate while in town
some 100+ miles one way away and tried them on different things here,
and could never quite stop my iMacG4 from broadcasting over AM radio.
The torroid magnets may be found under a more common name for a
home user in a package of two, from Radio Shack, part number 273-104
and they're called "Snap-on RF Chokes" an RF filter; in a package of two.
Different sizes can be found to wrap larger diameter wires
around, at least three turns. This kind of information is on
line if you search RF Chokes, or RF filter magnets. Good luck!