Under the cloak of a top-secret classification, an F-100F was rolled into a hangar at Long Beach, California, and placed in the care of North American's Kay Bullock, who had to find a place to stash the five boxes that made up ATI's system. Klemmick remembers Bullock's encyclopedic knowledge of the F-100 as vitally important, especially when first installing, and later repositioning, antennas after the Weasels had been deployed to Korat, Thailand. "He knew those airplanes so well that he'd take a big two-and-half-inch-diameter hole cutter, walk up to an airplane, and start drilling into the side of it," Klemmick says. "And the line chiefs are going, "Oh my Godthe fuel lines are in there.' "No,' he'd say, "I know exactly where I'm cutting.' And sure enough we'd shove an antenna there. No problem behind it."
The Vector IV system consisted of an array of small antennas mounted on the airplane to receive signals from every quarter. A panel of warning lights was mounted in the cockpit to indicate the type of signal being received: SAM, AAA, or conventional surveillance radar. A three-inch, television-like cathode ray tube was installed in each cockpit to provide a graphic indication of direction to the signal source. A WR-300 launch receiver, which was tuned to detect the burst of energy specific to a SAM launch, was connected to a bright red light in the cockpit, guaranteed to get the pilot's attention. Wild Weasel crews later referred to it as the "Oh shit" light.
The installation was crude and fast, and made use of commercial-grade wiring and other off-the-shelf components, but it enabled the first F-100F to be ready to fly in just 10 days. The system worked as advertised with only minor tweaks, and three more F-100Fs were rolled in for the same modifications. They were redesignated EF-100Fs for "electronic fighter," and flown to Eglin Air Force Base in Florida, where five volunteer crews selected to evaluate the system joined them on September 4, 1965.
Crew training was conducted at Eglin, which featured a full-scale Fan Song radar simulator being used to train B-52 Stratofortress and B-58 Hustler crews in electronic countermeasures techniques. The pilots and EWOs were encouraged to get to know each other and select their own partners, and there were adjustments to make all around--single-seat fighter pilots were not used to having another crewman on board, and most of the EWOs (soon to become known as "bears") were completely new to fighter operations. Bears were experienced EWOs, drawn mostly from B-52s and EB-66 electronic warfare aircraft.
At Eglin, the new equipment installed in the F-100s was constantly modified and adjusted even as new systems, some of them to be fielded on future aircraft, were still under development. It was at Eglin that Bob Klimec, an Air Force pilot and electrical engineer, solved some of the basic problems associated with pinpointing SAM sites, and developed the basis of a defensive system that would eventually be installed on different aircraft types, including the F-111 "Aardvark," which was soon to make its debut in Vietnam.
Klimec set out to improve on the existing RHAW system, which only told you that a SAM was looking, or launching, and gave only a general bearing to the radar source. At this early stage in anti-radar development, before specially designed missiles that home in on radar signals were available, the target still had to be visually acquired and attacked with conventional weapons like rockets, guns, or bombs.
The Fan Song was one of the first electronic scanning radars--it directed its energy without having to move its antenna. "The way the Soviets built the Fan Song was to have [one] radar that tracks both the aircraft and the missile," Klimec says. "It would scan across 20 degrees and then go off the air, because you had to shut the radar down in order to preclude any kind of problems with the energy coming back inside and blowing out equipment--and then it would fly back, come back on again, and scan 20 degrees, and go off the air." The radar cycled several times per second and was directed so that a targeted aircraft was located at the center of the scan sector, which enabled the missile to be maneuvered freely inside, while the target was simultaneously tracked by the radar.
"So it dawned on me that if we could detect when the radar came on, and we could determine when the aircraft was illuminated on the radar in the main beam, and we could detect when the radar shut down to fly back, we could calculate the position of the plane relative to the scan sector," Klimec says. It was known that the Fan Song took about 100 milliseconds to complete a scan, so if an aircraft was "painted" by the radar 50 milliseconds after the radar turned on, the aircraft was in the mid-point of the scan sector. "And the aircraft ordinarily did not get to the center of the sector unless somebody put him there--and since the tracking scan system could only track one aircraft to make an intercept on one aircraft, if you found yourself in the center of the scan sector and you found you stayed there, then you knew somebody had selected you as a target," he says.
After design engineers devised equipment to verify Klimec's theory, he began monitoring the Eglin Fan Song simulator's emissions from the top of a hangar. "I talked on the phone to the radar site and got them to move it a little bit, and we verified that we could detect when the radar came on to start the scan, we could detect when it went off the air, and we could detect when we got the large spike of energy as the main beam came by," Klimec says. Klimec's innovation eventually allowed fighter crews to know whether or not they were targets and to take action only if they were.
By the middle of November 1965, the Wild Weasels were committed to cutting their teeth in combat. Four EF-100Fs, led by Major Garry Willard, arrived at Korat Royal Thai Air Base on Thanksgiving day after a turbulent flight from Hawaii. Only 84 days had passed since the first F-100 had rolled into a hangar for transformation. But the equipment and tactics had yet to be proven. "Everything that went with the first contingent and with the first Weasels was all unqualified equipment," says Bill Hickey, a former ATI technician. "The need was so great we didn't have time to go through all the qualification testing and all that. And it worked, so who cared? But the biggest problem that anybody had was tactics, because nobody knew what the hell to do."