Newsgroups: sci.electronics
Path: utzoo!henry
From: henry@utzoo.uucp (Henry Spencer)
Subject: Re: Radar Theory
Message-ID: <1990Jan15.164544.29488@utzoo.uucp>
Organization: U of Toronto Zoology
References: <All> <this> <Radar> <stuff> <1990Jan12.042446.8799@waikato.ac.nz>
Date: Mon, 15 Jan 90 16:45:44 GMT

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
