IP: re: The cure is only slightly worse than the disease...: [risks] Risks Digest 21.78

[David Farber <dave () farber net>]

BTW, jammers will most likely find their dominant use as business 
generators -- like in airports where coin phone revenue is dying. There 
must be a national security reason for blocking cell phones!!

Dave

> Date: Fri, 23 Nov 2001 15:53:37 -0800
> To: farber () cis upenn edu, ip-sub-1 () majordomo pobox com
> From: "Joseph C. Pistritto" <jcp () jcphome com>
> .78
>
>
> actually, not true.
>
> All a cellphone jammer needs to do, is "act like a cell".  Then the 
> cellphone will "lock onto" the bogus cell (which will never place calls to 
> it).  For AMPS phones (US National analog standard) this is trivial.  It 
> used to happen by accident at CTIA shows all the time when people were 
> showing test equipment.
>
> Whats more, to be "louder" than the existing cell sites (which arent in 
> the hospital) requires very little energy.  The amount of energy in a 
> microwave door opener is more than sufficient.
>   -jcp-
>
>
> At 06:04 AM 11/23/2001 -0500, David Farber wrote:
>
> > > Date: Wed, 21 Nov 2001 12:56:57 -0700
> > > From: "Stewart, Russell" <russtew () sandia gov>
> > > Subject: The cure is only slightly worse than the disease...
> > >
> > > This story taken off of the newswire today:
> > >
> > > http://dailynews.yahoo.com/h/nm/20011121/od/tech_hongkong_champion_dc_1.html
> > >
> > > Concerns a signal-jamming technology being developed by a Hong Kong company
> > > to block cellphone calls in areas where they are not wanted. Not a bad idea,
> > > but the following excerpt caught my attention:
> > >
> > >   "A Hong Kong company hopes to sell signal-jamming technology previously
> > >   used by the military to thwart lethal missiles to block annoying 
> > > cellphone
> > >   calls in places such as hospitals, places of worship and restaurants."
> > >
> > > Hospitals? Now, I admit I know very little about jamming technology, but I
> > > know that, at the very least, it requires transmitting radio energy on the
> > > same frequency as the signal you are trying to jam. Presumably, it involves
> > > transmitting at a considerably higher power than that of the target
> > > signal. Now, as I understand it, hospitals' no-cellphone policy is based on
> > > the fear that the phones' radio transmissions might interfere with hospital
> > > equipment.  Are we to understand, then, that they intend to combat the
> > > problem by installing a device that, by definition, must transmit on the
> > > same frequencies at the same or considerably greater power?
> > >
> > > I hope this was simply an error on the writer's part...
> > >
> > > Russell Stewart, Sandia National Laboratories  russtew () sandia gov
> >
> >
> > For archives see:
> > http://www.interesting-people.org/archives/interesting-people/


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