[RFI] 40M QRM/RFI
jim at audiosystemsgroup.com
Fri Jan 12 15:35:21 EST 2018
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
> 73 Randy K0EU
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