“Two steps from Hell”
Great music!
A remembrance of the 10 day and night air battle over Hanoi at Christmas 1972
The US air assault began on 18 December with 129 B-52s approaching Hanoi. Hundreds of fighter aircraft taken off from 6 US aircraft carriers joined the attack. Good tactic: B52 bombers flew in formation, in successive waves made up three bombers.
The aftermath of the attack marked the end of US involvement in Vietnam.
Thats the last effort of US in VN and they tried everything they could.
Btw, u can read from my link to know more abt electronic warfare in VN, so next time when Cnese like Han-patriot brag that CN"super jamming decive" can jam VN missile, then u can give him a hard slap to wake him up
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TACTICS AND TECHNIQUES OF ELECTRONIC WARFARE
Electronic Countermeasures in the Air War Against North Vietnam 1965-1973
by Bernard C. Nalty
US Air Force F-105D Thunderchief is trying to evade V-750V SAM launched from a SA-75 Dvina, North Vietnam (US Air Force image).
_________
Linebacker II: The First Two Nights
By the time the B-52's launched Linebacker II, in December 1972, Fan Song operators had polished their skill in combating the bombers. As early as 9 April, near Dong Ha in South Vietnam, a SAM damaged an attacking B-52, the first missile hit suffered by a Stratofortress in seven years of Southeast Asia operation. On that day the first warning came when an electronic warfare officer on board one of the bombers in the three-plane cell detected a guidance signal. After the second B-52 in the cell had dropped its bombs and begun turning away, at least three missiles bored toward it. One of these exploded just 50 feet from the plane's left wing tip, puncturing the external fuel tank on that side and tearing into the fuselage. Despite the damage, Capt. Kenneth J. Curry landed safely at Da Nang. The absence of a Fan Song signal prior to launch indicated that the enemy had tracked the jamming source. [50]
When the Stratofortresses went North, SAM defenses were ready. The first of these planes damaged by a missile over North Vietnam was a B-52D hit by fragments while attacking Thanh Hoa on 23 April. Not until 22 November, however, did one of the SAM's destroy a B-52, a Thailand-based plane bombing a target 24 nautical miles northwest of Vinh. The pilot, Capt. Norbert J. Ostrozny, tried to fly the crippled aircraft to Nakon Phanom but lost control about 12 nautical miles from that base. The entire crew parachuted and was rescued within a few hours. [51]
In
shooting down Ostrozny's B-52D, North.. Vietnamese radar had provided accurate guidance despite electronic jamming by the victim, the other two bombers in the cell, and three EB-66's orbiting some distance away. As he approached the target, Captain Ostrozny had received additional protection from a chaff corridor created by four F-4's and from two Iron Hand F-105G'3. Throughout the approach, when the countermeasures were most effective, the radar operator had contented himself with passive tracking, simply following the jamming source across his scope. He allowed the B-52 to soar unchallenged to the release point. Then, as the plane turned sharply away after dropping its bombs, the wings formed an angle of roughly 45 degrees with the horizon, and the strongest part of the jamming cone passed ineffectually beyond the SAM site. At this instant, the Fan Song transmitted just long enough to pinpoint its target before the missile battery launched the two SAM's that exploded beneath the B-52. [52]
SAM controllers thus demonstrated that they had learned to take advantage of certain technical and tactical characteristics of the B-52. When Linebacker II began, the enemy already knew that the plane's jamming transmitters were least effective during sharp turns, that each Stratofortress habitually made just such a turn after dropping its bombs, and that formations usually attacked from about 35,000 feet. Armed with this information, the Fan Song operator passively tracked the jamming signal to determine azimuth and elevation, used the normal operating altitude to establish the range, then verified the range by transmitting for a couple of seconds as the three-plane cell was making its post-target turn.
These tactics minimized or entirely avoided exposure to anti-radiation missiles, and they enabled the enemy to catch the B-52 when it was most vulnerable to radar-controlled weapons. For the defenders, however, waiting for the post-target turn had an obvious failing-it permitted the bomber to reach the release point opposed only by barrage fire. [53]
The 207 B-52's in Southeast Asia carried an impressive array of countermeasures equipment that included the ALT-22 jamming transmitter, used against the Fan Song track-while-scan beacon, and the ALT-28, which could either reinforce the ALT-22 or engage in down-link jamming. By mid-December, all B-52's serving in this area mounted four ALT-28's and three ALT-22's, except for 41 of the 98 G models on Guam that carried older, less powerful ALT-6B's instead of the ALT-22's. Electronic warfare officers in the bombers usually directed two ALT-28's and two ALT-22's or ALT-6's against Fan Song and used the other pair of ALT-28's to jam the SAM guidance beacon. With the remaining ALT-22 or ALT-6, he usually attacked height-finder radars. [54]
Plans for Linebacker II B-52 strikes drew upon the experience gained during the spring of 1972. Out of respect for North Vietnamese antiaircraft guns, which had proved so deadly against Rolling Thunder fighter-bombers, the B-52's flew beyond reach of even the 85-mm weapon. At these altitudes, SAM's were their most dangerous, but the bombers maintained the three-plane cells which thus far had provided adequate countermeasures protection. To avoid mid-air collision, the cells kept 2 minutes apart.
During the first three nights, the Stratofortresses sought to minimize exposure to the SAM's by getting out of missile range as rapidly as possible, even though steeply banked turns of 113 to 160 degrees were required. The officers who approved these tactics realized that ;uch a turn was "a characteristically vulnerable position" because the "effects of both TWS and beacon jamming were minimized. " [55] They believed, however, that the greater speed in leaving the target area would more than offset the loss of jamming coverage. [56]
Linebacker II began on 18 December with 121 B-52's in three waves attacking seven targets near Hanoi. Supporting the first wave were 19 countermeasures aircraft: three EB-66's for standoff jamming, eight chaff-dispensing F-4's, and eight Wild Weasels for radar suppression. The second wave received the same countermeasures support, but as the third wave arrived, four Navy A-7's replaced the eight Wild Weasels, and five EA-3B's joined the EB-66's, their Air Force counterparts, in long-range jamming. [57] ^
Everything went well as the waves approached their targets. Capt. D. D. McCrabbe, an electronic warfare officer on board one of the bombers, felt that the SAM crews were "a little confused" at first, but the confusion ended as soon as the raiders had dropped their bombs. "We started doing our post- target turn and just all hell broke loose," the captain related. "They just started throwing everything at us." The enemy fired 164 missiles that night, downing three aircraft and damaging two others. All the hits occurred as the B-52's were turning' into wind of at least 71 knots and struggling to get out of SAM range. [58]
Pending completion of a detailed evaluation by the Security Service and the Air Staff, planners made minor adjustments in countermeasures support. For radar suppression, the first wave on the 19th could count on eight F-105G's, the second had ten and the third had four Navy A-7's. Eight F-4's laid chaff corridors for the first wave, two Phantoms sowed additional chaff for the second, and eight Phantoms preceded the final wave. Once again, five Navy EA-3B's joined three EB-66's already in covering the third wave.
^
The three B-52's lost the first night had been flying at 34, 000 feet, 38, 000 feet, and 38, 500 feet, and indication that the lowest and highest aircraft in the bomber streams had not received adequate chaff protection. As a result, base altitudes of 34, 500 and 35, 000 feet were established for the bomber cells, keeping all the aircraft closer to the center of a corridor sown from 36, 000 feet. And, in order to give the B-52's room to avoid approaching SAM's, the interval between cells was doubled to 4 minutes. This increased interval allowed the enemy more time for passive radar tracking, but the increased chaff coverage, plus the jamming barrage from the bomber cells, were expected to offset this advantage. [60]
No really drastic revision of B-52 tactics seemed necessary. As one of the aircraft commanders later pointed out, there really was no reason to change tactics at this point." The Stratofortresses, after all, had used the same basic procedures over Haiphong on 15 April and suffered no losses. "Sure," he admitted, "we lost some aircraft on the first day [of Linebacker II], but the area we flew in was better defended." On the second night, 19 December, no B-52's were lost, though two suffered damage, which seemed to confirm these views. [61]
H
ard Lessons are Learned
The tactics that worked on the second night failed on the third, as the sky came alive with 221 SAM's, 39 more than had been fired on the 19th. "Just watching all the SAM's, " said Capt. Bruce Kordenbrock, "was like watching a show until you realized they were starting to shoot at you." To Capt. D. W. Jameison, the enemy seemed to be "just salvoing off like six SAM's at a time, " of which "maybe one or two would be tracking." Other B-52 crewmen, such as Maj. L. M. Sweet, reported hectic radar activity on the night of the 20th, with as many as three Fan Song radars simultaneously tracking a single plane. A tail gunner saw three missiles, obviously guided from the ground, pursue his bomber through a hard left turn and explode within 750 feet of him. [62]
Below the bomber stream, Captain Kordenbrock saw a stratum of antiaircraft shells bursting so close together that "you could get out and walk on it." The scene reminded him of "all the war movies you've ever heard about. TSgt C. M. O'Quinn, the tail gunner whose B-52 had been chased by three missiles, believed "they were sending up triple A [antiaircraft artillery] and SAM's together. . . , hoping we'd dive to avoid the SAM's and fly through the flak. " Although the B-52's remained above 34, 500 feet and escaped flak damage, missiles downed six bombers and damaged a seventh. [63]
Until the Security Service could evaluate the role of countermeasures on the night of the 20th, three interim actions were taken to reduce SAM effectiveness during the strikes planned for the 21st. First, electronic warfare officers shifted one jammer from the Fan Song track-while - scan beam to reinforce the downlink jamming barrage. Second, planners decided to compress the bomber stream, stacking the cells from 33, 500 to 38, 000 feet and timing their arrival over the targets at intervals between 90 and 120 seconds. This decision reversed the 19 December policy of extending the bomber streams to keep the aircraft close to the center of the chaff corridor. Finally, plans for the night of 21 December called for two of the bomber streams, 24 of the 30 attacking aircraft, to avoid sharp turns, relying on their speed, boosted by the prevailing wind, to approach from the west and to depart eastward over the Tonkin Gulf. [64]
The countermeasures evaluation for the first night, which became available on the 23d, confirmed that the three bombers lost to SAM's on 18 December had received fatal hits during post-target turns, when their jamming was least effective. More significant was the disclosure that all three had belonged to "the cells in which no jamming was committed to the beacon (downlink) frequency." [65] The shift of emphasis from Fan Song to downlink jamming therefore appeared wise.
Initial comments on chaff effectiveness on the night of 18 December implied that the corridors had been satisfactory despite winds that varied from predictions by as much as 10 degrees in direction and 14 knots in velocity. Subsequent reports stated, however, that the three Stratofortresses shot down that night had been on the fringe of a ragged corridor. The difference between the predicted winds and the air currents actually encountered had disrupted the planned chaff coverage. [66]
When the Security Service analysis of the 20 December strikes arrived, it disclosed that chaff protection had been nonexistent that night. Plans had called for 27 of the 33 attacking cells to be protected by chaff corridors while within range of SAM sites. Although "many cells flew through some portion of the corridor" during the night's operation, "only four cells were actually in chaff at their respective bomb release lines and post target turns. " The six B-52's that fell victim to SAM's were from 5 to 10 nautical miles from the chaff concentrations when hit. The wind had again blown gaps in the coverage, forcing planners to think in terms of widespread blankets rather than comparatively narrow corridors. A shortage of chaff, however, caused postponement of this modification of counter- measures tactics. [67]
The evaluation of the third night's countermeasures effectiveness also sustained the decision, made in time for the 21 December operation, to substitute speed for steeply banked turns in getting out of SAM range. The Security Service reported that the missile batteries had again concentrated their fire upon B-52's in the post-target turn. In one case, the intended victim foiled the enemy by quickly leveling off and "re-injecting the protection noise jamming element during the terminal phase of the intercept." [68]
Study of the first three nights also led to a prohibition against using certain B-52 models over Hanoi-Haiphong. One of the three B-52's shot down on the 18th, and four of the six destroyed on the 20th were B-52G's carrying ALT-6 jamming transmitters instead of the newer ALT-22. For the rest of Linebacker II, therefore, bombers mounting the ALT-6 were restricted to less heavily defended targets. [69]
As the struggle against the SAM continued additional Navy aircraft joined the support force, with EA-6B's in engaging in stand-off jamming and A-7E's flying SAM suppression. Effective 24 December, chaff blankets replaced the corridors, and the bombers began releasing chaff in self defense. The B-52 electronic warfare officers received instructions to drop the radar reflectors whenever they detected Fan Song tracking signals during any turn sharper than 45 degrees and with a bank angle of 30 degrees or more. Although designed to confuse airborne radar, the chaff would also provide some extra protection during the dangerous post-target turn. [70]
Throughout Linebacker II, countermeasure tactics underwent analysis and revision. Tests at Eglin AFB indicated that the B-52 antenna radiation pattern was ill suited for downlink jamming. In addition, the enemy seemed to be using a modified SAM, fitted with a more powerful guidance beacon that was less susceptible to a modulated noise barrage. As a result, the B-52's that attacked North Vietnam on 26 December employed only two ALT-28's against the downlink. All other transmitters jammed the track-while-scan beam, except for one ALT-22 or ALT-6 directed against height finder radars and the I-band T-8209 signal.
When the electronic warfare officer detected the T-8209, he was to switch on his ALR-18 jamming transmitter. Although designed for the airborne radar carried by MIG interceptors, this device also had some value against the T-8209. [71]
The attacks of 26 December incorporated all the counter- measures lessons learned since the 18th. Plans for the operation combined precise timing with countermeasures protection, sending 120 bombers to attack 10 targets within 15 minutes. Careful selection of approach and departure routes brought the B-52's over seven targets almost simultaneously. Also, altitudes and interval varied to confuse the defenders, with some cells climbing or descending during the shallow post-target turn. Counter-measures support required 62 Air Force and Navy planes for stand-off jamming, SAM suppression, and chaff dispensing. [72]
The 24 F-4's laying chaff on 26 December put down two blankets, one west of Hanoi and the other over Haiphong. The six B-52 cells attacking Thai Nguyen, some 30 nautical miles north of Hanoi, had no chaff cloud to protect them, but certain of the bombers released chaff during the post-target turn, whether or not a Fan Song signal was detected. [73]
Despite the resourcefulness of those who planned the raid, SAM's claimed two B-52D's on the night of 26 December, scoring both hits in the vicinity of Hanoi. One aircraft received the fatal damage before releasing its bombs, but the other went down during its post-turn. The countermeasures plan was not at fault, however, for in both cases, one aircraft in the cell had turned back, depriving the remaining pair of vital jamming power. [
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