Randall K Martin rkmassoc at comcast.net
Fri Jan 12 16:44:22 EST 2018

I am fairly certain that one of the houses has a security system 
installed. Do these generally have some kind of main control unit that I 
could have him unplug as an easy test, or is it more involved than that. 
I'll find out if that is the source, before asking what can be done do 
cut down on the RFI.

Thanks Jim K9YC for your comments, too.


On 1/12/2018 2:36 PM, Leonard Halvorsen wrote:
> Are those 4 houses high-rent-district kind of places?
> Sounds like maybe a memory or sensor refresh on a security or fire 
> detector system.
> On Fri, Jan 12, 2018 at 3:24 PM, Randall K Martin <rkmassoc at comcast.net 
> <mailto:rkmassoc at comcast.net>> 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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