Re: Re: Radar scramblers

[kirby.a.smith@lmco.com]

DeWitt Harrison    de@aztek-eng.com  wrote:

 Adding the additional complication of doppler shifted return signal does
 not overcome the fundamental flaw in passive radar/lidar "jamming" devices.
 Whatever sort of reflected signal is returned from a doohickey equipped
 car will consist almost entirely of "car" and virtually nothing of "doohickey."
 Signal-to-noise-ratio. All you have to do is measure the square meters
 of the car's frontal area and compare it to the area of the passive reflecting
 device.  That ratio is signal to noise.  If we ignore the windshield area which
 may not be a good radar/lidar reflector, I think the car-to-doohickey-ratio
 would be something like 2 square meters divided by 0.0005 square meters.
 Fudge all you want, but the cop's supersensitive-califragilistic zapper will
 see all car and no doohickey. What we have here is a modern day sequel
 to "The King's New Clothes."  What is really needed is an inexpensive and
 legal radar/lidar/ovloV homing tactical nuclear missile.  Cheers,

The operative word is corner reflector.  I won't speak to radar, not my bag, but
your average bicycle reflector (made up of zillions of mini corner reflectors) 
has an optical crosssection of roughly 100 meters squared.  And it only occupies
an area of 0.0025 meters squared.

The above comment is not intended to support the idea of passive jamming (a 
contradiction in terms).  Passive countermeasuring may be doable, but is usually
difficult for a variety of reasons.  Better to transmit a deceptive or 
interfering signal.  However, if you want to avoid being an obvious jammer, you 
have to transmit a signal that looks like the return expected by the 
radar/lidar, but which supplies erroneous (but consistent) data.

An ovloV homing tactical nuclear missile - that would be even better than the 
GAU-8 (30 mm Gatling gun) I always wanted.

***                 ...Kirby    (Kirby A. Smith)                 ***
***                      2 X 1988 90q                            ***
***              ksmith1@mailgw.sanders.lmco.com                 ***
***              [=]   kirby.a.smith@lmco.com                    ***
***  Opinions expressed herein are entirely those of the author. ***