Case Studies in the Achievement of Air Superiority - Air Force ...

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jamming static with more powerful signals, switching radar broadcast frequencies,
and working radars of different frequency in pairs, so that the
second only broadcast when the first was jammed. More modern North
Vietnamese radars measured the energy level of returning signals. Higher
energy returns (the jamming signals produced by the EB-66) were filtered
out, leaving the original signals unaffected. EB-66 crews countered this
defense by matching the strength of their jammer signals to the echo or
return of the signal broadcast by the enemy tran~mitter.~~
Jamming was well worth the effort, but it was not possible to jam
SA-2 fire control from strike aircraft in August 1965, and the EB-66s did
not have the capability to operate in high threat areas over North Vietnam
without an escort of F-4s. In addition, jamming could draw SAM fire, risking
the jammer itself, as SA-2s guided along the jamming beam. On November
3, 1965, however, the base at Korat, Thailand, welcomed four F-100F
“Wild Weasel I” Radar Homing and Warning Aircraft, and these specially
equipped planes flew their first combat mission on December 3. The Wild
Weasels carried receivers which could detect and discriminate among the
GCI, early warning, and SAM fire control radars deployed in North Vietnam.
The equipment on the special planes could also detect radar emissions
from SA-2s and from any airborne-intercept radars that might be carried
by NVAF MiGs. The F-100Fs also carried special cameras and recording
devices to gather intelligence on SAM fire control radar.4y With Wild
Weasels in company, a strike formation would know when it was being
tracked, when it was being “illuminated” by SAM fire control radars, and
where the illuminating radars were located. Because their electronic equipment
operated passively, as opposed to jammers, which were active, Wild
Weasels did not attract SAMs. Moreover, they could direct SAM-suppression
F-105s (christened “Iron Hand”) to the area of SAM radar transmitters,
making life hot for North Vietnamese radar operators. Together, Wild
Weasel and Iron Hand were a major counter to the SA-2 fire control radar.
Though the SA-2 could also be guided optically until its terminal phase, the
continued use of Wild Weasel and Iron Hand drastically reduced SAM
effectivene~s.~~
In April 1966, Wild Weasel F-100Fs were first equipped with AGM-45
Shrike radar homing missiles. With Shrike, the F-100Fs could effectively
and quickly attack any SA-2 fire control radars that broadcast near them.
SA-2 radar operators could avoid attack by turning off their sets, but then
they could no longer target U.S. planes. SAM effectiveness dropped even
more with Shrike use; in 1965, one U.S. aircraft was shot down for every
thirteen SAMs fired; with Shrike, Wild Weasel strike escorts were more
than doubling the number of missiles needed to down a U.S. plane.5’ In
response, the NVAF, equipped by now with MiG-21s as well as MiG-17s,
rose from its protected bases at Hoa Lac, Kep, and Kien Am to challenge
U.S. strike forces. On April 23, two flights of MiG-7s under GCI radar
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