SIGINT planes vs. radioisotope mapping

[Dave Emery]

On Thu, Jun 05, 2003 at 11:52:14PM -0400, Randy wrote:
> I recall a few years back, a single satellite lost stability, and it pretty 
> much wiped out everyone's pagers, for
> a few days. Just my way of saying that I don't have any clue as to how much 
> point-to-point traffic may get
> relayed by a bird at some point.

	Within the continental US, very very little point to point
telephone traffic flows via satellite (hardly any in fact except a few
remaining private systems for companies and government - carriers
completely gave up satcom links about 15-20 years ago in the PSTN). The
economics don't work and people hated the delay in calls due to the
distance to the satellite.  The only real exception is parts of
back country Alaska... which is still served by satellite.

	There is still some international traffic on satellites, though
mostly to remote and underdeveloped places.   The great bulk of traffic
between the US and Europe and Asia is on fiber now.  Satellite does
provide backup to cables if they are cut, but more and more places
have enough redundant fiber to never need to use this capability.

	Until recently, most domestic PAGER traffic did flow via
satellites because it was cheaper to get it to the towers on remote
hilltops that way than by leasing fiber or copper circuits.  And indeed
when G4 died, a lot of pager transmitters had no input from the central
computers and went off the air.   Nobody had really thought about what
might happen if the bird died - they had been focusing on up link and
downlink reliability instead.   And in a very typical communication
screwup, some of the backups were on the same satellite.

	There has been some use of satellites for Internet IP traffic,
but again only a tiny bit compared to the flood that travels over fiber.
This is much more used for international Internet links, some of which
are on satellites.

	The major use of satellite capacity over the US is for video,
both broadcast and cable and direct to home, and for some innately
broadcast services like distributing weather data to airports and 
weather forecast offices and the like.  There are also some remaining
point of sale credit card verification networks on satellite because
of the reduced cost of a satellite link compared to thousands of circuits
to local gas stations or convenience stores. 

	And a lot of satellite capacity gets used for mobile terminals
for video uplinks for satellite news gathering and sports back hauls and
the like.   It is obviously not usually possible to provide fiber to the
scene of a major news event and only sometimes to the venues of sports
events.  And the military and government uses satellite capacity to
talk to things like Navy ships and mobile command posts which aren't
in one place very long.

	Very little travels by microwave anymore in the CONUS either
(maybe a couple of percent or less of wireline telephone calls do at any
point, perhaps even less by now - mostly to backward places where
stringing fiber is hard or uneconomical).   Most of the old AT&T microwave
towers that once dotted hilltops across the country have been shut down
and sold to cell operators or even private citizens seeking a remote
location for a cabin - and most of this shutdown happened by the late
80s in fact.  Very very few of the towers still in existence transmit
any traffic any more or ever could again.


> I seem to recall that, years ago, the 
> Transatlantic copper traffic entering and
> leaving the US was shot via microwave link to/from the US terminus, over a 
> bay, and allegedly there was a NSA
> farmhouse on the line-of-site path of the link. The implication being that, 
> yes, they "could" have just wired
> around the bay, but instead there was an intentional opportunity for 
> interception.

	There is an interesting microwave shot from Greenhill Rhode
Island (the landing site for around a third of the transatlantic cables)
and a point in Connecticut.   One may draw whatever conclusions one
likes about why this was done this way in the early 70s or so.

	I have seen an unnamed Telco insider comment on a public mailing
list that certain fiber Sonet rings linking a NJ cable landing site
(with another third or so of the cables) to a switching facility that
actually handles most of the traffic further inland have three nodes
on them instead of two.  No idea why... just one of those weird things
that got built that way in construction I guess.

> 
> And I'll point out that long-haul comms to submarines are done with RF 
> basically at audio frequencies, via
> buried antennas....yeah, they DO use very high power, but aircraft are 
> close and don't have salt-water and
> thick earth to penetrate.

	Submarine communications use very very low (80 hz) frequencies
from buried wires for a kind of paging function that says come up and
get the nuclear war order.   Actual messages are sent on VLF frequencies
(16-90 khz) which penetrate seawater better than other frequency ranges
and can be received while submerged to up to a couple hundred feet.  
Antennas for this function are not buried, but gigantic towers or mile
long wires trailed from command and relay aircraft.

	Aircraft (notably the Guardrail and Rivet Joint aircraft)  can
and do collect most any available radio signals they can see from flight
altitude.   This allows cellphones, cordless phones, pagers, pdas,
wireless email devices, and miscellaneous two way radio signals to be
vacuumed up and some microwave links to be intercepted as well, but 
none of these aircraft has ever been reported to routinely do TEMPEST
type interception of wireline traffic from incidental radiation.


> And if any of the copper is carrying digital data, square waves are hugely 
> rich in harmonics well up into the
> MHz bands, and would therefore tend to radiate better from any above-ground 
> wires between poles, possibly
> even roadside pedestals.
> 
	Actually FCC rules require things be built NOT to radiate all
that much because of interference to licensed services using precious
spectrum, so most wire communications devices fiber and copper radiate
very very little energy.  Part of this is due to the cancellation effect
of energy flowing in balanced transmission lines, and part due to
filtering and shielding.

	And there are myriads and myriads of information streams flowing
in typical aerial cables - even if the energy could be detected at a
distance (which it can't due to the impact of the inverse square law) it
would be nearly impossible to sort out the impulses from one circuit
from those of all the others in the same cable.


> And I've seen alot of RF off of traditional CATV coax; don't know if 
> fiber-optic cable systems might ultimately
> have any tie-in to the coaxial feed to/from the headend.
> 
	Cable TV systems have rather high level VHF and UHF rf flowing
in them.  There is constant problem for cable companies with corrosion
and damage to the wires causing some of this energy to leak out and be
radiated and cause interference to licensed services on the same
frequencies.  Cable companies spend lots of dollars going around looking
for and fixing these problems in order to avoid fines and other legal
action by the FCC and FAA.

	Modern cable companies use fiber optics to transmit the signals
from the headend where the satellite dishes and antennas are to a
neighborhood where they are converted from optical to rf on copper and
distributed locally.

	And optical fiber does not radiate at all at radio frequencies.
The only source of rf radiation in fiber optic systems is the
electronics at either end which convert the light into electrical
signals for local use.

	One problem that most naive paranoid types completely fail to
grasp is the titanic volume of modern communications.  The flow is so
overwhelming that only a powerful God could possibly process it all to
find interesting material.   The entire federal budget could not pay
enough humans to screen and analyze ALL the electonic communications of
even a medium size city in 2003.    So communications intercepts are
necessarily targeted very narrowly, even drag net fishing is likely done
only in places where there is a real likelihood that something important
will turn up with finite effort.
	
	The notion that an all powerful big brother is listening to
everything and capturing everything just is not realistic, and a very
very high percentage of what does get captured is never looked at or
listened to or even stored for very long.

	Which of course is why traffic analysis and transaction analysis
and social network discovery is far more important than flying airplanes
around trying to collect incidental radiation from local copper T1
lines. Knowing who calls or emails who makes it possible to find the
needles which you want to monitor in the vast haystacks.   Thus there is
a much greater probability that records of your calls and IP traffic
addresses are looked at for patterns and association with known bad guys
than that someone is actually listening to or reading your traffic
looking for the word bomb.


-- 
	Dave Emery N1PRE,  die at die.com  DIE Consulting, Weston, Mass 02493
PGP fingerprint 1024D/8074C7AB 094B E58B 4F74 00C2 D8A6 B987 FB7D F8BA 8074 C7AB