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Re: [RFI] 40M QRM/RFI

To: rfi@contesting.com
Subject: Re: [RFI] 40M QRM/RFI
From: Jim Brown <jim@audiosystemsgroup.com>
Reply-to: jim@audiosystemsgroup.com
Date: Fri, 12 Jan 2018 12:35:21 -0800
List-post: <mailto:rfi@contesting.com>
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
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