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From: commgrp@silver.ucs.indiana.edu (BACS Data Communications Group)
Newsgroups: sci.electronics,rec.autos
Subject: Re: Detecting Radar Detectors
Message-ID: <53005@iuvax.cs.indiana.edu>
Date: 2 Aug 90 14:58:03 GMT
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bbesler@vela.acs.oakland.edu (Brent Besler) writes:
>The insurance Gestapo wanting to ban radar detectors is nothing new.  
>...
>The radar detector detector picks up the 11.5 Ghz reference signal 
>most detectors put out.  MAYBE the new Solo, which is pretty low 
>powered and uses a GaAs FET rather than a Gunn diode may not be 
>detectable by it.  Anybody on sci.electronics who would know the 
>answer please share it with us.

The Gunn diode is a simple/inexpensive but inefficient (about 2%) way 
to produce microwaves. That's the main reason why most radar detectors 
require so much power that it is impractical to operate them from 
internal batteries.  (Although the physics are different, you can 
think of a Gunn diode as a LED which emits microwaves instead of 
light, except that it must be inside a resonant cavity to do so, and 
the cavity determines the microwave frequency.)

The new generation of radar detectors (e.g. Solo) with FET local 
oscillators require less DC power, however, the local oscillator RF 
level is probably the same as in older types, and probably has 
equivalent leakage.

--

Frank Reid     reid@ucs.indiana.edu
"Aha!  The alien Zorg battle cruiser's BMW disguise is flawed by a 
suspicious lump on the dash.  Set nuclear nerd neutralizer to medium-
well!"