Date: Thu, 02 Sep 1999 08:51:44 -0700
From: Doug Jones <random@qnet.com>
Newsgroups: sci.space.policy
Subject: Re: Russia Finds New Way To Scam Americans

Pat wrote:
>
> Jens Lerch wrote:
>
> >
> > You are free to take $10,000 with you without declaring it.
> > But there are no signs or information sheets telling you that and
> > you don't even see custom officers while leaving the USA for
> > Western Europe. This may be different if you leave to countries
> > with a less friendly partnership with the USA.
> > Maybe there is a way to check for money at the x-ray/metal detector
> > you have to pass, though I don't see how they could see the
> > difference between a bunch of $1 bills in the wallet and $1000
> > bills, without opening it and browsing through it.
> >
>
> take a look at the new US bills,  that dark thread in the left
> side, is a small tuned antenna.  They use a RF scanner near the
> clearance point, to check for a large signature.  If you wrap
> the bills in aluminum foil then the X-ray detector, sees that
> and guards unwrap the bills.

pat, this is urban folklore.

A) That strip is a piece of plastic film with the denomination printed on
it, with no electromagnetic signature.  All new US currency has them, clear
down to ones.

B) Magnetic inks are used, but they are so weak as to require a contact
sensor to detect (an anti counterfeiting measure).  Even a thick roll of
bills (40 twenties by personal experience) will not trigger an airport
security metal detector.

C) Thin aluminum foils are essentially transparent to x-rays, and would not
be detected by a luggage scanner.

D) Even *if* an RF tag were placed in currency, a few seconds in a
microwave oven would cure that... (I just checked a $20 by this technique-
the ink got warm, and the denomination strip was unaffected.) Incidentally,
this technique could have been used to sweep the then-new US embassy in
Moscow that was laced with diodes to saturate bug-sweeping efforts (ah, the
game of espionage).

Currency smuggling is still countered by the high technology of the Mark I
K9 nose.

--
Doug Jones, Freelance Rocket Plumber