🚀 go-pugleaf

In article <Apr.8.17.57.00.1990.17771@topaz.rutgers.edu>, jjoshua@topaz.rutgers.edu (Jon Joshua) writes:
> 
> Date - 1980.  Person is driving a '79 Monte Carlo through town.  All
> of a sudden the windshield cracks.  It was not caused by a kid
> throwing rocks because the crack was rather straight.  Anyway the
> person pulls off the road and a cop pulls up a few seconds later.  The
> cop had been using radar and the windshield had a built in antenna
> wire.
> 
> Could radar hitting the wires in the glass cause them to resonate so
> much that the glass cracked?
> 
I doubt that the electromagentic energy emitted by the police radar would
have the effect that is mentioned here. First, the power output of a radar
gun is relatively low. Following the inverse square law, the amount of energy
received at the car would be a fraction of the radiated energy. This would
hardly be enough energy to crack a car window (did you ever see how hard it
is to crack tempered glass?). Second, since the wavelength of a radar signal
is very small, a car antenna (wire) is not an effecient antenna for the
microwave radar signal. Thus, not much of the radar signal will be received
by the car antenna.



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Brian K. Daly WB7OML @ AG Communication Systems, Phoenix, Arizona
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