From: serafin@epcot.spdc.ti.com (Mike Serafin)
Subject: Re: Quick radar question about traffic ticket
Organization: TI Semiconductor Process and Design Center
Date: Thu, 5 Nov 1992 21:56:16 GMT

In article <Bx9EMo.2F9@mentor.cc.purdue.edu> mshar@mentor.cc.purdue.edu (Mike Mshar) writes:
>In article <1992Nov4.215533.2792@erg.sri.com> rat@erg.sri.com (Ray Trent) writes:
>>In the referenced article, mshar@mentor.cc.purdue.edu (Mike Mshar) writes:
>OK, then, what is the amplitude of a radar gun`s emmited radiation? I
>understand the microwave part, i.e. the holes in the screening are smaller
>than the amplitude of the waves, therefore the waves make contact with the
>metal screen as they pass through, and are therefore absorbed. But I was
>under the impression that radar waves were not very powerful, and did not

NO, the wavelength of the radiation determines what size opening will let it
pass.  The amplitude has nothing to do with it. 

>have a large amplitude. So, my reasoning was that they would be able to
>pass through a radiator. Besides, doesn`t the clear plastic door panel of a
>microwave oven reduce the energy of the exiting waves to the point where
>they are not harmful to humans? I know that when your car is parked in the
>sun, UV waves go through the glass into the car. On their way through the
>glass, some of their energy is lost, and thus they are reduced to infrared
>waves. When this happens, the waves no longer have enough energy to pass
>back through the glass, so they just bounce around and are absorbed inside
>the car, thus producing the heat. 

NO, the sun emits UV AND IR radiation.  The glass on your car absorbs a great
deal of UV, while passing a great deal of IR.  All of the other surfaces in the
car are very effective at absorbing the IR and that's where all the heat comes
from.  

>Doesn`t a microwave oven door do the same
>thing to waves coming out of it??

No, the microwaves do not come out of the oven.  They are reflected back into
the oven by the screen on the door.  

>About the body panels, also, I had assumed that because the waves had a
>very small amplitude that they would bounce off of the individual surface
>irregularities on the bady panels. Therefore, the waves would be scattered
>by the bumps and cracks in the paint of the panels. Also, the waves would
>bounce off things that you mentioned, engine block, radiator, headlights,
>bumbers, etc. 
>
>So, in essence what I am asking is, what is the amplitude of police radar
>waves?? Being an ME, I am clueless as to what it might be. 
                           ^^^^^^^^ this is quite obvious

The amplitude of police radar is very small - low intensity.  On the other hand
the question you may be asking is what is the frequency of police radar?  I
don't have a reference handy, but I believe X-band is somewhere around 6-8 GHz
and K-Ka band are 10-12 GHz.  

>Anybody have any info??
>
>Jeez, if you are going to go that far, just buy some radar absorbant
>material from the government, and coat your car with it. Or just buy a good
>radar detector, and try not to speed. :-)
>
Radar absorbing materials are okay, but you typically can't hide things like
headlights, license plates, etc, that make perfect reflectors.  And there is a
company that makes a stealth bra, that will help a little.