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Re: V3 #1014

In Artical 1014, Paul Caneiro says:

From: Paul Caneiro <PCaneiro@squareone.com>
Date: Wed, 11 Sep 1996 00:39:52 -0400
Subject: RE: quattro-digest V3 #1010

 Well here goes:

I have the V1 with the Laser detector and I frequently drive in Ct.
where they use Laser for enforcement of speed.  I also have mounted
behind my lower grill on my A4Q a single 5"round fog light with a
100watt h1 bulb.  I wired this to a relay and connected this to fog
light to the battery. Oh, I forgot, I covered this bad boy with a lens
that will only transmit light in the IR spectrum. Coincidentally this is
also the same spectrum that the laser guns work in.  

In total darkness you cannot tell the light is on.

<egregious revenue enhancement avoidance story deleted>

I believe that this type of protection works because the output and
frequency of the light emitted from my light is more powerful then the
reflected pulses off of my car.  This prevents the Laser gun from
properly measuring the frequency of the pulses that are being reflected
off of the car back to the gun. kinda like laser overload.

In my cas the $100  was well spent on the detector and the $150 on my
project was also well worth it.

I hope this helps


Paul, et al.  I think the effect is due to the shot noise generated by the 
detection of any "dc" source, such as the headlight.  The shot noise is 
proportional to the square root of the detected power.  If this is commensurate 
with the radar pulse return power, it will be hard for the receiver to separate 
the real pulse from the noise.  The output of tungsten, halogen and xenon lamps 
is very strong in the band likely used by a laser (diode) based radar (more 
properly a ladar).  It seems very likely, without analysis, that a headlamp 
would be strong enough to jam it.  The laser radar manufacturer should ....

***                 ...Kirby    (Kirby A. Smith)                 ***
***              ksmith1@mailgw.sanders.lockheed.com             ***
***              [=]    kirby.smith@lmco.com                     ***
***  Opinions expressed herein are entirely those of the author. ***