[RFI] RFI Identification Help

Paul Christensen w9ac at arrl.net
Wed Nov 13 10:03:37 EST 2013

> It doesn't seem to be on at night, so
> wonder what might run during the day with this type of cycling that 
> wouldn't
> be running at night.

You won't know until you get out and localize the source.    There are all 
kinds of things that run during the day and not at night.  For the last two 
weeks, switch mode noise was apparent on 160m during 10am and 4pm only. 
What kind of device could emit that noise only during those hours?  Answer: 
a human being.  A contractor was charging high-capacity batteries with a 
switch-mode charger while he was on the job site.  A neighbor is having him 
install a room addition.

Maybe this example begins to show why we need to stop thinking about what it 
could be, and just use some brain power on our legs to find the source. 
Guesses as to street lights, night lights, etc., are only going to slow you 

Despite my pontificating, I was guilty of this thinking myself.   Years ago, 
I posted screen shots and asked "what could this be?"  Dozens of answers 
came back and not one of them was helpful in finding the root cause.  That 
made be a believer in Frank Haas' philosophy of not assuming anything.

Paul, W9AC 

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