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From: billk@hpsad.HP.COM (Bill Katz)
Newsgroups: sci.electronics
Subject: Re: the undetectable radar detector
Message-ID: <1840016@hpsad.HP.COM>
Date: 2 Dec 89 02:57:30 GMT
References: <89333.113354BHB3@PSUVM.BITNET>
Organization: HP Signal Analysis Division - Rohnert Park, CA
Lines: 30

Brent Beseler writes:

>Would the following idea work:
>
>Suppose the reciever horn of a detector is mounted in front of the engine grill
>etc. in a hidden location.  Right behind the horn would be a microwave amplifie
>r circuit.  That would feed into a cable.  The cable would run to a well shield
>ed reciever.  This system would not emit the 11.5 Ghz frequency that the
>radar detector detection systems use.
>                                          Brent H. Besler
>                                          FOrd Motor Scientific Res. Lab


	Yes, it is possible for a system such as you describe to be built
that would not radiate the local oscillator.  In addition to a preamp, a
filter would also help.  (You would ideally have a separate filter/preamp/
mixer for each band)  As you state you would also need a well shielded 
receiver.  This is a non-trivial task, depending on how close you want to 
be able to get without your LO being detected.  Shielding 11GHz effectively
is tough, but can be done.  I doubt it can be done at the prices they sell
commercial radar detectors for.

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