spt@waikato.ac.nz (Simon Travaglia) (01/12/90)
I'm pretty baseline about how detectors work etc. Can someone explain or mail me how the theory of it works. (I understand the basics of reflections etc, is it Dopler-ish?) What's to stop you syncing in with the Speed Detector and sending back info to say that you are doing 500mph? Slower may not work because the radar would probably settle for the highest conmtinuous speed, so why not tell it that you are absolutely hiking along. And when you get stopped in your 1963 1.3l ford for pulling 540mph, you need simply say "Yeah sure..." "...take me to court" -- %SYS-E-NOSIG, signature file mutilated by foreign power. %SYS-I-DEFSIG, using emergency signature Simon Travaglia, University of Waikato, Hamilton, New Zealand. Disclaimer: "Sorry about that cheif!"
henry@utzoo.uucp (Henry Spencer) (01/16/90)
In article <1990Jan12.042446.8799@waikato.ac.nz> spt@waikato.ac.nz (Simon Travaglia) writes: >What's to stop you syncing in with the Speed Detector and sending >back info to say that you are doing 500mph? >... And when you get stopped in your 1963 1.3l ford for pulling >540mph, you need simply say "Yeah sure..." > "...take me to court" And he'll say "That sure is an interesting-looking gadget on your dashboard there..." "...You're under arrest. You have the right to remain silent..." Quite apart from the small matter of you not being licensed to transmit in the police-radar bands, both the police and the courts would probably consider this "obstructing a police officer in the performance of his duties". Which is a far more serious crime than speeding. "Serious" as in "jail sentence and criminal record". Legal aspects aside, there's nothing hard about sending back a false signal that overpowers the real one (the radar probably locks onto the strongest signal, and reflections are fairly weak), although you'd have to be careful to stay within the limits of the radar unit. A signal saying "500 mph" is probably beyond what the radar's electronics are willing to consider as plausible, and possibly beyond what they can receive at all. That is, it might just light up its "something's wrong" light, or it might ignore your signal altogether and go for the next strongest one. -- 1972: Saturn V #15 flight-ready| Henry Spencer at U of Toronto Zoology 1990: birds nesting in engines | uunet!attcan!utzoo!henry henry@zoo.toronto.edu
kelly@uts.amdahl.com (Kelly Goen) (01/16/90)
In article <1990Jan15.164544.29488@utzoo.uucp> henry@utzoo.uucp (Henry Spencer) writes: >In article <1990Jan12.042446.8799@waikato.ac.nz> spt@waikato.ac.nz (Simon Travaglia) writes: >>What's to stop you syncing in with the Speed Detector and sending >>back info to say that you are doing 500mph? >>... And when you get stopped in your 1963 1.3l ford for pulling >>540mph, you need simply say "Yeah sure..." >> "...take me to court" > >And he'll say "That sure is an interesting-looking gadget on your dashboard >there..." > > "...You're under arrest. You have the right to remain silent..." > >Quite apart from the small matter of you not being licensed to transmit >in the police-radar bands, both the police and the courts would probably >consider this "obstructing a police officer in the performance of his >duties". Which is a far more serious crime than speeding. "Serious" as >in "jail sentence and criminal record". > >Legal aspects aside, there's nothing hard about sending back a false signal >that overpowers the real one (the radar probably locks onto the strongest >signal, and reflections are fairly weak), although you'd have to be careful >to stay within the limits of the radar unit. A signal saying "500 mph" is >probably beyond what the radar's electronics are willing to consider as >plausible, and possibly beyond what they can receive at all. That is, it >might just light up its "something's wrong" light, or it might ignore your >signal altogether and go for the next strongest one. >-- >1972: Saturn V #15 flight-ready| Henry Spencer at U of Toronto Zoology >1990: birds nesting in engines | uunet!attcan!utzoo!henry henry@zoo.toronto.edu CHeck out of copies of 73 magazine , Ham Radio(for 10.525 ghz designs) and Radio Electronics(had a radar calibrator article a few years ago) also Car and driver had an excellant article on Baseband Pulse jamming techniqu a few years ago... AND as long as we are on the subject I have a set of the Benton Harbor Instrument "RADAR CALIBRATOR" boards built up... anyone know where I can find dual band X+K 150mw output Gunnplexor modules??? cheers kelly
erc@khijol.UUCP (Edwin R. Carp) (01/17/90)
In article <1990Jan15.164544.29488@utzoo.uucp> henry@utzoo.uucp (Henry Spencer) writes: >In article <1990Jan12.042446.8799@waikato.ac.nz> spt@waikato.ac.nz (Simon Travaglia) writes: >>What's to stop you syncing in with the Speed Detector and sending >>back info to say that you are doing 500mph? >>... And when you get stopped in your 1963 1.3l ford for pulling >>540mph, you need simply say "Yeah sure..." > >And he'll say "That sure is an interesting-looking gadget on your dashboard >there..." > > "...You're under arrest. You have the right to remain silent..." Having been a police officer, I can testify with some authority that the cop'll probably look at his radar gun, swear under his breath, and call in to his dispatcher and complain about his radar. The dispatcher will probably tell him (or his sgt.) to go back to the shop to get another one. You'd probably not even get stopped, because it'll look like the radar's gone nutso. Most cops don't have the technical sophistication to realize that the dumb thing's *not* a CB or radar detector. -- Ed Carp N7EKG/5 (28.3-28.5) uunet!cs.utexas.edu!khijol!erc Austin, Texas (512) 832-5884 "Good tea. Nice house." - Worf
jb@aablue.UUCP (John B Scalia) (01/18/90)
In article <1990Jan15.164544.29488@utzoo.uucp> henry@utzoo.uucp (Henry Spencer) writes: >Legal aspects aside, there's nothing hard about sending back a false signal >that overpowers the real one (the radar probably locks onto the strongest >signal, and reflections are fairly weak), although you'd have to be careful >to stay within the limits of the radar unit. A signal saying "500 mph" is >probably beyond what the radar's electronics are willing to consider as >plausible, and possibly beyond what they can receive at all. That is, it >might just light up its "something's wrong" light, or it might ignore your >signal altogether and go for the next strongest one. Indeed, they do this, or at least the Kustom Signals KH-11 does this. This used to be, I haven't paid attention lately, one of the best "smoking gun" units the troopers could get. A couple of us, local road racers of the legal on-the-track types, managed to have a state trooper time us on the straightaways. We were told the max the KH-11 would register was 165mph and upto 200mph, it simply flash the 165 reading. I don't recall being told exactly what it would do beyond this, other than a higher signal would be rejected. The trooper, though, had all kinds of problems with us as we were using very low slung, tube framed, fibreglass bodied formula cars with basically zip frontal area for reflecting the signal, although I got clocked at 135mph in my Formula Ford. I think if you were to try something like a nonsense jammer, pick a value around 140mph absolute or a +70mph relative. I shouldn't think any unit would have a problem with these numbers, and who'd believe it anyway? For what it's worth, jb@aablue.UUCP -- A A Blueprint Co., Inc. - Akron, Ohio +1 216 794-8803 voice UUCP: {uunet!}aablue!jb (John B. Scalia) Just a little more nonsense to clutter up the net.