From: sdw@lig.net (Stephen D. Williams)
Date: Sat, 26 Nov 94 23:50:44 PST
To: cwedgwood@mserve.kiwi.gen.nz (Chris Wedgwood)
Subject: Re: bug-finder?
In-Reply-To: <m0qzxNz-000KFyC@mserve>
Message-ID: <m0rBZme-0009xvC@sdwsys>
MIME-Version: 1.0
Content-Type: text/plain


> 
> ddt@lsd.com (Dave Del Torto) wrote
> >>Anyone here know a source for a listening-device ("bug") detector?
> 
> In my (very lkimited) experience this is NOT an easy thing to detect. I have
> pulled apart some comercial bug detectors, usually the contain a 556 and some
> LEDS witha speaker. One did actually have anoise diode and a little counter
> so's to make things seemingly randmo and more real.
> 
> In reality it is quite difficult to detect ALL bugs. Whilst at a guess most
> will be FM (50-150 Mhz) there is still the possibility they use other
> (prob. higher) frequencies. I good scanner might pick them up - provided it
> is sensitve enough and can scan fast enough as there is quite alot of 
> spectrum to cover.
> 
> Chris

I thought the trick was to use a 'near-field' receiver.  I saw one at
the Dayton Hamvention a couple years ago for about $100.  It'd receive
Am audio or sync on FM (you'd here no-noise silence they said).

You don't tune it: it relies on the 'near-field' effect which is
something about how transmitters can induce the right harmonics in
a certain type floating receiver within a short distance.  The Rabbit
TV extender and a stereo TV decoder used the same method: they
sat on top of the TV and 'noticed' which channel you were on.

sdw
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