From: Steve Schear <azur@netcom.com>
Date: Wed, 9 Jul 1997 04:20:56 +0800
To: Dave Del Torto <ddt@lsd.com>
Subject: Re: Spread Spectrum Surveillance Modules
In-Reply-To: <v04000809afe7ff5de7bd@[192.187.167.52]>
Message-ID: <v03102800afe844ca8728@[10.0.2.15]>
MIME-Version: 1.0
Content-Type: text/plain



>[From the TSCM-L Technical Security Mailing List]
>
>................................. cut here .................................
>
>TSCM Intelligence Update - Spread Spectrum Surveillance Modules
>
>New Spread Spectrum Surveillance Modules
>
>There are some new spread spectrum products coming into the US by way of
>China, and are starting to show up in Spy Shops on the West coast, Chicago,
>and Miami area.
>
>Two sided, four layer, surface mount PCB, several RF and audio IC's,
>several pots, coils, etc. Device is a raw module, designed for covert
>installations in an office or SOHO environment.
>
>SM connector for antenna, micro molex connector for power and
>computer/serial interface.
>
>PCB is 1.5 mm wide, 3.25 mm long, and .5mm thick.
>
>Products are all based on a cordless telephone chip set, 780 Mhz to 980
>Mhz, Direct Sequence Spread Spectrum (BPSK/QPSK?).

Unfortunately, all high volume consumer direct sequence (DS) chips are
optimized for data throughput and spectral efficiency, the exact opposite
of what you want for surveillence.  The compact sinx/x DS signature is easy
to see on any spectrum analyzer when one is relatively close to the bug.
However, if the DS chip is used in combination with frequency hopping (FH),
especially if the hop frequencies overlap, then a much more robust
surveillence device can be created.  Introduction of FH does complicate the
design, especially receiver acquisition/synchronization, but the results
could be well worth the effort.

--Steve

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        God grant me the serenity to accept the things I cannot change;
        The courage to change the things I can;
        The weapons that make the difference;
        And the wisdom to hide the bodies of the people that got in my way;-)

        "Surveilence is ultimately just another form of media, and thus,
        potential entertainment."
        --G. Beato

       "We've all heard that a million monkeys banging on a million
        typewriters will eventually reproduce the entire works of
        Shakespeare. Now, thanks to the Internet, we know this is
        not true."                           -- Dr. Robert Silensky