mapping in the sierras and places west

[John Young]

Aren't these kind of rigs used to survey, triangulate and record
large numbers of ground-based transceivers?

If so, they are similar to rigs which do geological surveys
with packs of machines you can see traversing likely oil
reserves. Odd looking, six or so trucks, bumper to bumper,
running 50 yards or so, pausing, an almost inaudible 
hammering on the ground, then rushing ahead to the
next stop. Logs of these soundings are reportedly
transmitted directly to home base, encrypted, so the
trucks cannot be hijacked or intercepted by competitors.
So the wishful thinking goes.

In the case of aerial surveys of radio frequencies, it is
possible to spoof signals by tucking the genuine in amongst
"static." But successful evasion depends on the snoopers
not have quick-witted algorithms to snatch the static,
even if it's burst transceivals, and make sense of it.

If you encrypt the sneaky signal you're dead meat.

Again, learning from the oil patch pirates, you can lay off
over the horizon and grab the sounding data by reading
the ground signal in the clear not the encrypted air data. 
But beware of chaff sent out by the trucks to thwart that 
such angle snooping.

Some packs of trucks are reconnaissance by fire.
As are some of the aerial surveys, which invite
tracking of the overt apparatus to snatch the pirates'
interceptions by way of reverse engineering the
snoop with an array so large you wouldn't know it
was there unless you had an antenna capable of
reading it. Some locate components of the
secondary receiver city-wide, or maybe wider.

Some radio engineers think the mobile phone system
transceivers are used for that very, very wide array 
purpose tucked dual-use below the consumer usage.

Would mobile phones also serve as unwitting contributors 
to a large area transceiver? Sophicticated geological sensors 
can certainly get pretty good readings from heavy traffic
on the interstate, and it gets better as the highways
deteriorate. Concrete expansion joints are wondrous
impactors.