Path: utzoo!utgpu!jarvis.csri.toronto.edu!clyde.concordia.ca!uunet!cs.utexas.edu!sun-barr!newstop!texsun!pollux!attctc!sampson
From: sampson@attctc.Dallas.TX.US (Steve Sampson)
Newsgroups: sci.electronics
Subject: Re: Radar gun zapper: fact or fiction?
Message-ID: <10781@attctc.Dallas.TX.US>
Date: 30 Dec 89 15:30:41 GMT
References: <74719@psuecl.bitnet> <1198@ariel.unm.edu> <10657@ucsd.Edu> <74896@psuecl.bitnet>
Organization: The Unix(R) Connection, Dallas, Texas
Lines: 24

In article <74896@psuecl.bitnet>, peg@psuecl.bitnet (PAUL E. GANTER) writes:
> Seriously though, I have heard tales
> of HAM's jamming (not destroying) radar guns, and people putting
> magnetrons on their cars (effective birth control?).  Anyway, what
> I wanted to know was how (in theory) the thing might work.
> 

I haven't seen any magnetron jammers yet.  Hams don't jam anything other
than HF and at least one local repeater :-)  However, what your looking
for (inexpensively) is an AM jammer.  The CW radar is looking for a Doppler
Shift between its transmiter and receive target frequency.  It uses a simple
crystal diode radio.  With enough power you can mask all other targets by
modulating a carrier with the appropriate Doppler Shift for the microwave band
in question.  The crystal diode radio will then process only this shift.  This
works poorly against stationary radars and ineffective against moving radar.
AM jamming is the worst selection in any radar technical book.  A test by
Car and Driver into the effectiveness of this type of jamming, proved that they
didn't work.  By the way, the next issue of Radio-Electronics claims to have
a radar detector tester.  Oh no...  These will invariably end up on the
turnpike and freeways with the mental midgets turning them on at various times
to watch your radar detector lights.  Masters and Johnson had a name for this,
but I forget...

Steve, N5OWK