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Re: [RFI] Frequency-Specific Interference

To: "Hisashi T Fujinaka" <htodd@twofifty.com>
Subject: Re: [RFI] Frequency-Specific Interference
From: "KD7JYK DM09" <kd7jyk@earthlink.net>
Date: Wed, 29 Feb 2012 09:51:04 -0800
List-post: <rfi@contesting.com">mailto:rfi@contesting.com>
: Also, loop antennas are pretty well known. It wouldn't be hard to create
: a loop tuned at a specific frequency. Use it with a receiver and you can
: have a very directional null.

Of all things, I do NOT have a loop, nor have I ever played with one.  It IS 
on my list of things to try, especially for tracking down 11m Class C 
Telemetry signals, my main interest.

Currently I use an Icom IC-706MKII with a 24" wire antenna and up to 161 dB 
of attenuation and a older RDF unit I am quite familiar with.  The RDF unit 
has such a sharp null you can sight down it like a hand-gun and determine 
which of two objects a foot apart on a power pole is creating noise at a 
distance of about 75'.

I can track down a 4W signal inside a building on a "rubber duck" antenna 45 
miles away, pinpoint a pole with arcing hardware just by driving by it, 
ruling out all other external sources and pinpoint a single bolt on a pole 
once I get out and "sweep" it.

This, with a few common sense thoughts and some footwork is only my personal 
experience, it has worked flawlessly in all instances and I like to tell 
others about doing it with items most of us have and techniques we can all 
understand.

Kurt 

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