[Scan-DC] (no subject)

[Albert LaFrance]

Actually, the great common-carrier microwave networks which once spanned the
country are essentially gone, replaced by fiber optics.  I recall reading
that about 98-99 percent of AT&T's traffic now travels via fiber, with the
remaining microwave to be phased out in the next few years.  Most of the
towers have already been sold.  At one time the AT&T microwave network
consisted of about 2000 stations, with tens of thousands of individual
transmitter-receivers.

As you suggest, microwave links are quite vulnerable to interception.
Although the antennas are highly directional, they do have useable side
lobes, and often it's feasible to place an intercept antenna directly in the
line of sight.  In the past, most of the transmission used analog
frequency-division multiplexing, whose highly standardized and
well-documented format made it rather easy to extract individual voice
channels.

I understand that, because of the risk of interception, AT&T implemented a
program to ensure that circuits carrying potentially sensitive
communications would be carried only on coaxial cable (the other major
high-capacity transmission technology in the pre-fiber era), because
circuits on such cables are much more difficult to intercept.

Today's digital fiber-optic cables are, of course, infinitely more difficult
to tap without the carrier's cooperation, and modern encryption technology
further complicates the task of intercepting communications.

BTW, I maintain a couple of web sites which might be of interest:

http://longlines.addr.com  (the former AT&T microwave radio and
coaxial-cable networks)
http://coldwardc.homestead.com/files/index.html (U.S. Cold War C3I
infrastructure)

Albert LaFrance

----- Original Message -----
From: "Steve Rigby" <srigby@smart.net>
To: <Scan-DC@mailman.qth.net>
Sent: Saturday, June 29, 2002 7:10 PM
Subject: Re: [Scan-DC] (no subject)


>    It is my understanding that e-mail messages being relayed from one
> point to another through established, commercial microwave sites are
> subject to being monitored.  It is a virtual certainty that any such
> messages routed via any communications satellite are monitored.
> Certain 'keywords' are looked for in text messages, and upon the
> discovery of any such 'keyword,' that particular message may be
> 'captured' and scrutinized in greater detail.
>
>    The same applies to cell phone calls.  When one reads or hears
> that some government intelligence agency has intercepted an
> electronic message between some suspected evildoers, how do you
> think that eavesdrop has came to pass?  Quite often, a revelation of
> such eavesdropping in the news will reveal that many of these
> intercepts were gathered before the individual was even known to
> authorities or was suspected of any wrongdoing.  Indeed, such
> intercepts often offer the first inkling that any untoward
> activities are being contemplated.
>
>    Almost all of these intercepts are performed without any warrants
> or court orders, and are, in essence, 'fishing expeditions.'  Much
> of this occurs under the aegis of "Echelon," an alliance between the
> United States, Great Britain, Canada, New Zealand and Australia, and
> is also allegedly used to reveal intelligence information pertinent
> to business interests as well as for more standard law enforcement
> and government intelligence purposes.
>
>    Steve