[RFI] Frequency-Specific Interference

KD7JYK DM09 kd7jyk at earthlink.net
Wed Feb 29 12:16:50 PST 2012

"What kind of device makes an arc-like noise, yet is so defined in its 
spectrum? And the fact that it avoids the amateur bands seems like a clue in 
this age (hopefully waning) of BPL."

You can hear that it's random arcing of various amplitude, so most likely 
not BPL or similar, even the best Military encryption systems will have an 
obvious interleaving sound to them.  I've heard many recordings of such data 
systems and regret that I worked for a company developing it over a decade 
ago.  I didn't know it at the time, yes, I expect there is a special place 
in Hell for me due to that...

I once had a situation here with a damaged CFL light bulb that seemed to 
have some frequency specific characteristics, not specific notches in Ham 
bands, but a meg or two missing here and there and nothing detectale above 
8.5 MHz or so, which made it suspicious.  As it turns out, these notches 
were determined my the wiring in the house, an odd mixture of radiators and 
chokes at various frequencies on HF due to the layout.


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