stewart@ihlpf.UUCP (R. J. Stewart) (03/17/86)
I wonder how hard it would be to turn a car "black" well into the infrared range? Actually, the usable range for infrared speed traps may not be very wide, since at some point the heat being radiated by the car would interfere with the detector. Bob Stewart ihnp4!ihlpf!stewart
eric@chronon.UUCP (Eric Black) (03/19/86)
>I wonder how hard it would be to turn a car "black" well into the >infrared range? > >Actually, the usable range for infrared speed traps may not be very >wide, since at some point the heat being radiated by the car would >interfere with the detector. > >Bob Stewart >ihnp4!ihlpf!stewart I don't think I'd like my car to be completely "black" at IR during the summer! Prolly not even during the winter. It's hot enough reflecting all the heat it does now... Rather than absorb the IR laser, I'd rather jam it by sending my own noise (lots of random heat). I wonder whether a laser of sufficiently low power to be safe for use in public really would be useful what with all the background noise it would have to deal with. If it's not significantly cheaper than the hand-held radar units, and may not be more reliably used under expected conditions, why would a PD buy one? The small radar guns that are on only when you're being clocked defeat radar detectors for the most part, unless your detector hears the traffic in front of you being clocked, and it takes a pretty smart detector/driver to distinguish that short signal from the local bank/Burger Thing... -- Eric Black "Garbage In, Gospel Out" UUCP: {sun,pyramid,hplabs,amdcad}!chronon!eric VOICE: (415) 941-0403 US SNAIL: Chronon Computer Corp. 2570 El Camino Real W. Suite 206 Mountain View, CA 94040
aptr@ur-tut.UUCP (The Wumpus) (03/22/86)
> >I wonder how hard it would be to turn a car "black" well into the > >infrared range? > > > > I don't think I'd like my car to be completely "black" at IR during > the summer! Prolly not even during the winter. It's hot enough reflecting > all the heat it does now... Rather than absorb the IR laser, I'd rather > jam it by sending my own noise (lots of random heat). > To make the car "black" to IR in the true sense would mean the absorbtion of IR waves, but there are other ways to make the car appear to be black to IR. The physical effect known as Thin-Film-Interference allows things to appear to be black while not actually being so. Have you ever noticed a pool of water with a slight bit of oil in it deffracts light? Well that is one example of thin film interference. What is happening in thin film interference is that the light is reflected both by the top and bottom surfaces of the film in such a manner that the light reflected from the top and bottom are 180 degrees out of phase with each other, and therefore cancel each other. The only real problem with using this to block out IR is that you are talking about put a coat of paint on that must be correct to under 10e-10 m, but with todays technology it isn't to hard. Oh yes, I also believe that it would mean that you would never be able to wax your car again because of the changes the wax would cause. The Wumpus UUCP: allegra!rochester!ur-tut!aptr BITNET: aptrccss@uorvm