On Feb 17, 12:57 pm, Jim Wilkins wrote:
On Feb 17, 11:07 am, wrote:
...



Even better - how did we map out the Soviet's Tall King air defence
radar network without direct photo coverage, and the Sovs going silent
whenever the ELINT airplanes were flying around?

--
Pete Stickney

OTH?

Nice writeup. Thanks.

Jim Wilkins

http://www.tbp.org/pages/Publication.../F99Poteat.pdf

The Oxcart mission planners were especially concerned
about just how widespread the Soviet's early-warning
radar was and where it was located. It seemed impossible,
however, to determine the number, exact location,
or any other technical information on those installations.
I recalled a story from my Cape Canaveral days in the
early 1950s, when the signal from a ground-based radar
located nearly a thousand miles beyond our horizon
was picked up at the Cape -- the signal was reflected
off a Thor missile during a test flight. The suggestion
was then made that this same phenomenon (later called
bi-static intercept) could be used to intercept Soviet
high-powered radar located well over the horizon by pointing
the ELINT antennas at the Soviet ballistic missiles
during their flight testing, by using the missile's radio beacon
for pointing, or simply programming the ELINT antennas
to follow the missile's predicted trajectory.
The idea to gain greater knowledge of Soviet air
defense capabilities through bi-static interception was
approved by CIA management, and project Melody was
born. There were no computers in those days, so our
feasibility studies and engineering calculations involved
solving spherical trigonometry equations using slide
rules, tables of logarithms, and hand-cranked calculators.
Melody was installed at a CIA monitoring site on
the shores of the Caspian Sea in northern Iran. Over
the ensuing years, Melody produced bi-static intercepts
of virtually all the ground-based Soviet missile tracking
radar, including all their anti-ballistic missile tracking
sites located at a test range nearly a thousand miles
away. The fixed location of Melody and limited trajectories
of the Soviet missiles being tracked, however,
still did not provide the locations of all the air defense
radar installations throughout the Soviet Union that
were needed by the Oxcart mission planners.
A new Soviet early-warning radar, called the Tall King,
began to appear about this time, which if deployed
widely, appeared to improve significantly the Soviets'
air defenses. The new, very large, and obviously powerful
Tall King radar quickly became the Oxcart's nemesis


Melody's success with the high-powered, missile related
radar led to the idea of using the moon as a distant
bi-static reflector to intercept and locate the Tall
King radar systems deployed in the Soviet Union.
At the same time, the Lincoln Laboratory, America's
premier radar-development house, had been engaged
in a "radar astronomy race" with its Soviet counterpart
to see which side would be first to detect and characterize
the moon's surface using radar. Lincoln won
handily. I visited Dr. John Evans at the labs and discussed
the moon radar results and the bi-static moon
idea. Drawing on the labs' understanding of the moon
as a reflector of radar signals, sensitive ELINT receivers,
tuned to the Tall King frequency, were attached to
the giant 60-foot RCA radar antenna just off the New
Jersey Turnpike near Moorestown and pointed at the
moon. (The labs' giant radar antenna was preoccupied
with further radar astronomy experiments.) The
ELINT receivers were also optimized for the effects
of the moon as a reflector, that is, using the lab's
"matched filter" techniques. Over time, as the Earth
and moon revolved and rotated, all the Soviet radar
sites came into view one at a time, and their precise
geographic locations were plotted. The extremely large
number of installations that were found, and the rather
complete coverage of the Soviet Union, were not good
news for the Oxcart program office -- or for the U.S.
Air Force Strategic Air Command, which had to plot
wartime bomber penetration routes.