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In 1965, several F-100Fs were modified for the role of identifying, marking, and attacking North Vietnamese SAM sites, particularly their radar installations. Applied Technology Inc. did much of the early work. This company began by adapting electronic equipment that had originally been developed for the U-2. In the system which eventually emerged, the F-100F was provided with an AN/APR-25 radar homing and warning receiver which was capable of detecting the S-band signal emitted by the North Vietnamese SA-2 fire control radar as well as the C-band signal emitted by upgraded SA-2 systems and the X-band signals emitted by enemy airborne interception radars and radar-guided antiaircraft artillery. A cockpit display included a "threat panel" plus a cathode-ray tube which showed the bearing of the threat signal. An AN/APR-26 receiver was fitted which detected missile guidance launch signals by sensing a power change in the enemy's command guidance radar signal and flashed a red launch warning signal light in the cockpit. An IR-133 receiver was fitted, this receiver having a greater sensitivity than the APR-25 homing and warning receiver and having the additional capability of indicating the nature of the threat by signal analysis.
The modified F-100Fs carried the usual load of 20-mm cannon ammunition plus a pair of LAU-3 canisters loaded with 24 rockets which served as markers as well as weapons which could demolish a radar site. Fighter-bombers accompanying the F-100F would then attack the target with iron bombs. The project was given the name *Wild Weasel*, after the fierce little mammal which has a reputation of being so fearless that it pursues its prey into its very den.
The first F-100F Wild Weasel I aircraft arrived in Southeast Asia in November of 1965. The first Wild Weasel F-100F combat mission was flown on December 3. The missions were flown under the codename *Iron Hand*, and the antiradar missions were usually flown by one F-100F accompanied by four F-105s. The F-100F would identify and mark the radar site for attack by the accompanying F-105Ds. (compiled from a variety of sources)