Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!uunet!motcid!svoboda
From: svoboda@motcid.UUCP (David Svoboda)
Newsgroups: sci.electronics
Subject: Re: Detecting Radar Detectors
Message-ID: <4355@ash31.UUCP>
Date: 14 Aug 90 15:52:52 GMT
References: <26c63bee-32e.10sci.electronics-1@vpnet.chi.il.us>
Organization: Motorola Inc., Cellular Infrastructure Div., Arlington Heights, IL
Lines: 29

From article <26c63bee-32e.10sci.electronics-1@vpnet.chi.il.us>, by cgordon@vpnet.chi.il.us (Gordon Hlavenka):
> 
> If the output power of the gate stealer is sufficient, the actual return
> will be completely masked.  By calibrating to your vehicle's speed, it is
> possible to set the unit to produce any desired reading on the radar gun.

I'm probably WAY out of my league here, as I've never worked with doppler
radar before, but...

As I understand, doppler radar sends a frequency which is reflected from the
target which is moving towards or away from the gun.  The gun receives the
doppler shifted reflection amplifies it, and mixes it with the original 
transmitted frequency to obtain a beat frequency which is proportional to 
the relative speed of the target.  Now, it seems possible that if you fed 
the receiver the appropriate BEAT frequency at a high enough level, then the 
amplification and mixing process would produce predominantly the beat
frequency that you fed it, thereby giving a false reading, with no need of
vehicle speed calibration.

I seem to remember a construction article in Radio Electronics several years
ago on a "Personal Auto-triggering Radar Calibrator", which did just this,
and even sensed the current being drawn through your radar detector to
automatically trigger.  Of course, who would want to have to actually turn
it on MANUALLY to calibrate their home radar units?  :-) :-)

           Dave Svoboda, Motorola CID, RTSG, Arlington Heights, IL
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