[CW] Strange interference

[Donald Chester]

This interference covers the entire HF spectrum - from 80m to 30 mHz, 24/7 
for the  last couple of months.  It is spaced intervals of approximately 
30.475 kHz.  On an AM detector it sounds like a tone modulated carrier, but 
careful observation shows that there are two distinct carriers heterodyning 
against each other; one is unmodulated and the other has a spastic but 
barely perceptible frequency shift of a few Hz, and each shift initiates 
with a click. The frequency shift averages about twice a second.

The higher in frequency, the greater the spacing of the carriers.  At 30 
mHz, they are a little over 800~ apart, on 20m. they are a little over 400~ 
apart, on 40 they are 200+ hz apart, and on 80m about 100~ apart.  Although 
the signals appear approximately every 30.475 kHz, some frequencies are much 
stronger than adjacent ones.  There are a few holes in the pattern, where 
nothing is audible on the expected frequency.

The signal appears to be local, since it comes in on 10m all the time, and 
the S-meter remains stationary, thus excluding  the liklihood that it is 
skywave.  The higher in frequency, the stronger the signal.  It is louder 
than my xtal calibrator on 10m, but on 80m it is almost buried in the noise.

Here are a few of the frequencies I measured that  fall inside the ham 
bands:

29.998826/29.999660 mHz

14.884912/14.885340 mHz

7.373734/7.373935 mHz

3.618225 kHz

The signal is extremely stable; I notice no drift over a 24-hour period.

It is not something in the house, since I cut the a.c. power at the main 
utility entrance and the signal is still there.
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Anyone ever heard anything like this?

Don K4KYV