[FCARC] RF in your radio shack

[Adam T. Cately]

Hello -

    Here is a quoted message that I pulled from a Reddit 
'r/amateurradio' post - if you have RF in the radio shack issues this 
might be the solution . . .


  After 3 years of fighting RF in my shack I finally fixed it in an
  afternoon. The answer was embarrassingly simple and I want to save you
  the same 3 years

"Symptoms: key clicks on transmit, audio distortion on receive, computer 
peripherals acting weird when I keyed up, neighbors' speaker buzzing. 
What I tried over three years: better feedline, better connectors, 
adding ferrites randomly, moving equipment around, a different ground 
rod, a second ground rod, reading 47 forum posts that all contradicted 
each other
What actually fixed it: a single common-mode choke at the feedpoint of 
the antenna, and a second one where the feedline entered the shack. Two 
chokes. Each wound with 8 turns of coax on an FT-240-31 toroid. Total 
cost: $18

The theory I finally understood: I didn't have a grounding problem. I 
had a common-mode current problem. Those are different problems with 
different solutions, and treating one like the other does nothing. Most 
RF interference in ham shacks is common-mode current, not a lack of 
earth ground

If you have RF in your shack and you haven't built common-mode chokes 
yet, start there. Before the fancy ground system, before the filtered 
power strip, before anything else."


de KB8MDF

-- 
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     Adam T. Cately
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