I only wish I had less experience tracking down RFI. At least here in
the city, dogs and guns aren't a great hazard. I do wish, however, that
my utility was as responsive as Ignacy's.
73,
Scott K9MA
On 1/21/2021 7:03 PM, Ignacy Misztal wrote:
A few weeks ago I asked for help with RFI on my "dream" rural ham-radio
property. A powerline-type noise was present 24h/day and was strongest on
15m peaking S5. Readings from beverages and 4 sq were inconsistent but a
15m beam indicated 270 degrees towards the main road a quarter mile away.
However, 3 el sniffer (MFJ-856) could not copy anything strong, and a
magnetic loop indicated a different direction every couple of steps.
Solving the problem required overcoming fear of dogs (nearby), guns (heard
almost every day) and the courage to walk a private dirt road from the
main road. In a quarter mile I found an abandoned industrial building, with
a pole next to it. The sniffer was overloading! However, the sniffer did
not provide consistent readings until about 300 ft from that pole. When
called, the local power company fixed the issue the same day.
A few lessons. It seems that 15m travels really well on the power lines
(more than 1/2 mile in this case), and the combined re-radiation from many
poles leads to false directions. Second, the VHF sniffer needs to be really
close to get consistent readings. Third, in the country a ham needs to
overcome the fear of dogs and guns, and walk on private dirt roads if
necessary. Finally, rural EMC may be much faster than those in the city but
they need locating the source of RFI.
I owe a great deal to Scott K9MA who has immense expertise in solving RFI
and guided me to solve the problem.
Ignacy, NO9E
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Scott K9MA
k9ma@sdellington.us
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