[RFI] Persistence Pays Off in eliminating a Nasty RFI Source

K8TB k8tb at bosscher.org
Sat Dec 12 05:46:56 PST 2009

    I once traced interference to a 2 meter repeater to one of those 
preamps in the loft of the garage. Six miles away! The owner was only 
so-so to deal with. They had switched to cable, and this was a 300 ohm 
in/out preamp, so the output cable was simply tossed back by the preamp, 
which caused the oscillator to form. He kinda figured out what it was, 
pulled the AC plug and the interference went away. Then it came. "What 
incentive is there for me to keep this unplugged?" While one might be 
tempted to thump ones chest and spout off FCC regs, his wife was 
standing there. I simply stated, "Well, an unused TV preamp consumes 
electricity, for no reason, and it is now a fire hazard." "Herbert, you 
take and throw that thing in the trash right now!". He went back up and 
grabbed it and handed it to me.
    Finding the interference is only half the battle. Neighborhood 
diplomacy can be the real effort.

          tom K8TB

Dennis Vernacchia wrote:
> This from Bruce KQ6B in Valley Center ( rural ) CA
> Bruce writes:
>  As you may know, I've had a noise problem here for years. ....
> It turns out that up in the attic of my neighbor's house  the previous owner
> had a TV antenna and an amp (either a pre-amp or a distribution amp).  When
> the owner finally located it and unplugged it and the coax, the noise
> problem essentially went away.

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