earle@miracl.DEC (Re-entrant list structures alter DNA) (02/13/86)
Simple question, I hope easy answer: I have a vinyl nose mask on my car. It has cloth backing. The way it covers those nose allows almost no metal to be seen while looking straight on the front of the car. There might be a little metal to be seen from the top of the mask to the bottom of the windshield but it isn't very much because the sloping of the roof isn't that great at that point. The car is a Starion so there isn't much of a 'grille' on the front. The vents leading into the engine are two horizontal slots for the width of the car. The opening is fashioned out of plastic not metal. The headlights are retractable and they have covers for them too. Can't see much of the roof either. My question: Is the front of my car 'stealthy' (sorry for the word, but what the h*ll); i.e. will it make a bad reflector for radar signals? George Earle DECVAX!DECWRL!RHEA!OBLIO!EARLE PS: Anyone ever use a radar interference unit? What do you use it for if all the ads say "be carefull in use when near police radar"?
hsu@eneevax.UUCP (Dave Hsu) (02/14/86)
In article <1113@decwrl.DEC.COM> earle@dec-miracl.UUCP writes: > > George Earle > DECVAX!DECWRL!RHEA!OBLIO!EARLE > >PS: Anyone ever use a radar interference unit? What do you use it for if >all the ads say "be carefull in use when near police radar"? Simple: you bring it with you to college baseball games, to prevent major- league scouts (and/or opponents' reconnaisance teams) from clocking your pitcher; what else? :-) -dave -- David Hsu Communication & Signal Processing Lab, EE Department <disclaimer> University of Maryland, College Park, MD 20742 hsu@eneevax.umd.edu {seismo,allegra}!umcp-cs!eneevax!hsu "They were the elite, the vanguard of progress. They would take mankind to the heights...and perhaps beyond." -Arthur C. Clarke, Childhood's End
brian@sdcsvax.UUCP (Brian Kantor) (02/18/86)
As someone who's done a little bit of experimenting with radars (I own two radar guns; one is a surplus police model and the other is a sport radar, and yes, they're licensed to me), its my distinct impression that the best reflection comes from radiators and firewalls. That is, the cars with slanted radiators and firewalls don't read at nearly the distance that those which present a more plane surface to the incoming "beam" do. Of course, if you WANT to show up on the radar, you can build yourself a simple radar corner from some cardboard and aluminum foil. I suspect there isn't much you could do to reduce the amount of radar reflective area on your car without some structural modifications. The radar signal seems to go right through plastic noses and get the metal behind it; I'd sort of expect that as reasonable behaviour. Perhaps there are special plastics that do better at absorbing radar than others, but most cars are still metallic enough that it might not help. This is for X-band; I don't (yet) have a K-band radar to play with. Brian Kantor UC San Diego decvax\ brian@sdcsvax.ucsd.edu ihnp4 >--- sdcsvax --- brian ucbvax/ Kantor@Nosc "There is more harmony in films than in life." - Francois Truffaut
jim@sivax.UUCP (Jim Bauman) (02/18/86)
> In article <1113@decwrl.DEC.COM> earle@dec-miracl.UUCP writes: > > > > George Earle > > DECVAX!DECWRL!RHEA!OBLIO!EARLE > > > >PS: Anyone ever use a radar interference unit? What do you use it for if > >all the ads say "be carefull in use when near police radar"? > > Simple: you bring it with you to college baseball games, to prevent major- > league scouts (and/or opponents' reconnaisance teams) from clocking your > pitcher; what else? > Building a "radar interference" unit is easy (and effective). The idea is not to send out a signal that says "I'm doing 30mph (what if yer in a 20 zone!), but to send out a signal that changes pulsing frequency so rapidly that the police radar doesn't have a chance to "lock in " on ANY particular speed. The hardest part about building one of these is finding inexpensive gunn diode oscilators. Bauman sivax
stewart@ihlpf.UUCP (R. J. Stewart) (02/19/86)
> Simple question, I hope easy answer: > > I have a vinyl nose mask on my car. It has cloth backing. The > way it covers those nose allows almost no metal to be seen while looking > straight on the front of the car. > ... > My question: Is the front of my car 'stealthy' (sorry for the word, > but what the h*ll); i.e. will it make a bad reflector for radar signals? Not likely. Remember that three things can happen when electomagnetic radiation hits an object: the radiation is absorbed, reflected, or transmitted. If your nose mask reflects, it's as easily detected as metal. If it transmits, the signal will simply be reflected off the metal behind it (this seems most likely). It's unlikely that it would absorb the signal (though you might watch to see if your engine temperature guage goes up next time you pass a radar trap :-) Bob Stewart ihnp4!ihlpf!stewart