View Full Version : squeezebox interference

2004-07-10, 08:32
Since this has been brought up, I was prompted to go and measure the
RF interference that my squeezebox is generating.

I notice it mostly in the AM band on the tuner, and it is worst on
the station in the middle of the waveband, which happens to be
the only AM station I listen to.

The noise pattern is 0.25 seconds at basically one dominant frequency,
followed by 1.03 sec. at a slightly lower frequency (about 100 Hz
I guess the main frequency I hear (1.5 to 2.5 kHz) is some demodulation
and not the base frequency, so it probably doesn't mean much by itself.

There are several observable stages:

1. When power is applied, the two-step pattern is repeated
around a certain frequency while the SB initialises.

2. After 9 seconds the dominant frequency suddenly drops by ~ 1kHz,
but the two step 0.25/1.03 sec. pattern continues. The frequency
gradualy drifts, presumably with warm-up of the SB. I can let it sit
there, or play music,
or put it into standby mode (display black) and it makes no difference.

3. The only way to remove the RFI is to completely remove the power to
the SB.

I use a wired, not wireless, connection.
The RFI is the same whether or not I have the antenna screwed in.
Moving components about changes amplitude slightly, but not enough to be
It seems to be radiated, not carried down any wire.