Jim Brown jim at audiosystemsgroup.com
Fri Jan 12 15:35:21 EST 2018

Hi Randy,

Yes, I often see signals like these on the P3 spectrum display on 160 
and 80 CW. They are likely generated by a microprocessor that's part of 
a control system some sort appliance or the component of a home 
entertainment system.  Thankfully, at my QTH, they're never very loud. 
OTOH, trash from switching power supplies and solar systems often IS.

73, Jim K9YC

On 1/12/2018 12:24 PM, Randall K Martin wrote:
> I have recently noticed a 24-hour per day source of QRM on 40M CW. On 
> 7031.9 there is a steady stream of dashes, with the dash lasting about 
> 1.5 seconds and then a space of 0.5 seconds. What is interesting is 
> that there is a second signal which is much weaker on 7041.9 which is 
> the exact inverse of the first. When the first signal is on, the 
> second is off, and vice versa. Both sources peak at the same heading, 
> roughly 90 degrees from my main 40M yagi.
> I have zeroed in on a spot about 2000 feet east of me where the main 
> signal is almost 40 dB over on a mobile rig (K-3 with hamstick). I've 
> ordered a DF loop antenna so I can try and pin it down further before 
> knocking on doors. There are four houses in the immediate vicinity.
> Just wondering if anybody in this group has ever come across something 
> like this. Google searches and archive search for this reflector came 
> up empty. The signals do not drift in frequency. Speculation as to the 
> source?
> 73 Randy K0EU
> _______________________________________________
> RFI mailing list
> RFI at contesting.com
> http://lists.contesting.com/mailman/listinfo/rfi

More information about the RFI mailing list