Airtunes - picking up radio signals

Question

Using an iMac G5, with iTunes 9.03, Airport Express with v6.3 firmware.
When I stream audio to my stereo I get radio signals coming through in the background. Very annoying at lower volume. Only way to get rid of it is to raise the volume quite loud. I thought at first it was just the extremely old receiver I have, then I tried it with a more modern system and got the same results.
When I stop playing music in iTunes, the sound still comes through the stereo for a brief bit before stopping (10 seconds or so) - I assume because when nothing is playing streaming is paused.
Any clues on how to block out the unwanted frequencies? Internet robustness is on, and I couldn't find any settings anywhere in the airport admin utility that might help.
I'm very close to enveloping the airport express in copper shielding
Any ideas would be greatly appreciated.

Answer 1

Reminds me of my grad school days in Rochester, NY, when vinyl was the source of all music. I had a decent stereo system for an impoverished student, but imagine my surprise when I learned, and not gently, that the phono cartridge in my turntable was perfectly attuned to receive the radio frequency used by the Rochester public transit bus dispatcher, whose signal was very strong indeed. I might be grooving along to Jefferson Starship, the Grateful Dead or Pink Floyd, gently ratlling the windows throughout our apartment and adjoining houses, puffing on a little of this or a little of that, when without warning I would be jolted out of my chair and across the room by an ear-shattering interjection of static-laden and distorted verbiage about the University Avenue local D bus, whose driver had just been vomited on my a drunk and needed advice about how to handle it. It was a real mood-spoiler for me. I replaced my phonograph cartridge and the problem was solved