HISTORY

VIETNAM WAR USAF ECM PODS

AN/ALQ-87

AN/ALQ-71

AN/ALQ-71

The initial bombing of North Vietnam began on 3 March

1965. Known as Operation ROLLING THUNDER, it lasted

until 30 October 1968. North Vietnam was defended by to

SA-2 Guideline (Soviet designation V-750 or S-75) Surface-toAir-Missiles (SAM) that relied on the SNR-75 fire control and

tracking radar, known by its NATO code name of FAN SONG.

The SAMs forced the attacking aircraft (primary F-105D/Fs) to

fly at lower altitudes, which made them vulnerable to AntiAircraft Artillery (AAA), much of which was directed by the

SON-9 FIRE CAN radar. Electronic Countermeasures (ECM)

pods were introduced by the USAF to defeat these radars.

Since the primary threat, the SA-2, was only found in North

Vietnam, when looking at contemporary photos from the war,

if an aircraft had ECM pods, it was headed for North Vietnam.

If it didn’t, it was going to South Vietnam, Laos or Cambodia.

It’s helpful to know how the FAN SONG radar worked. This,

believe it or not, is a VERY simplified explanation! (Since

the Vietnam War, NATO has changed the radio frequency

band designations. For this explanation, the original band

designations are used.) The FAN SONG had three antennas:

•

A rectangular vertical trough that tracked target

elevation operating in the F-band using vertically polarized

beams. The U.S. ECM antennas that addressed azimuth were

referred to as EVEN antennas.

•

A horizontal trough that tracked target azimuth

operating in the E-band using horizontally polarized beams.

The U.S. ECM antennas that addressed elevation were

referred to as ODD antennas.

•

A dish antenna at the end of the horizontal trough

sent guidance signals to the missile in C-band, with the missile

responding in F-band.

The SA-2 missile had two stages. Once the first (booster)

stage burned out and fell away, it uncovered the ‘beacon’

antenna at the back of the second stage, allowing the Fan

Song’s dish antenna to guide the missile using a sequence of

three-pulse groups known as ‘triplets’.

The initial variants of the AN/ALQ-71 and AN/ALQ-87 were

each composed of two cannisters which contained two

transmitters each. Initially, the pods were configured with

two jammers assigned to barrage jam the Fan Song with the

other two jamming AAA radars.

The QRC-160-1 was the pre-production variant of what

became the AN/ALQ-71. It was used on three 45th TRS RF101Cs flying out of Tan Soh Nhut AB (near Saigon) on 29

April 1965. Each jet carried four pods! They used two pylons

with either one pod, or two using a dual adapter (the only

50

eduard

AN/ALQ-101

Author: Jim Rotramel

published photograph of an RF-101C with a QRC-160-1 shows

a single parent-mounted pod). The RF-101C was not designed

with wing pylons and the jury-rigged installation had adverse

effects on the aircraft and the aerodynamic vibrations

damaged the pods. So, this poorly thought out experiment was

quickly ended. The pods themselves were then made more

physically robust (including the addition of two hardbacks on

the top of the pods) and redesignated QRC-160A-1.

As losses of F-105D/Fs mounted during 1966, the idea of

using ECM pods was revisited. Despite some initial misgivings,

the 355th TFW at Takhli RTAFB began carrying QRC-160A-1

pods on 26 September 1966. The pods proved so successful

that soon every 355th jet was carrying pods under both wings!

However, there was a limited number of pods at the time

(about 140), so half were given to the 388TFW F-105D/Fs

at Korat RTAFB. By November 1966 all F-105D/Fs flying over

North Vietnam were equipped with QRC-160A-1s. The most

famous use of the QRC-160A-1s was during Operation Bolo

in January 1967, when 8th TFW F-4Cs borrowed some pods

and pretended to be F-105s. Carrying the pods on the right

outboard wing pylons, they lured 11 North Vietnamese MiG21s into a trap, shooting down seven.

Production versions of the QRC-160A-1 pods, known as AN/

ALQ-71(V)-2, began arriving in Thailand in December 1966.

During this initial time period, the F-105D/Fs flew in carefully

defined four-ship ‘pod’ formations to maximize jamming

effectiveness. Lead (#1) carried a pod mounting EVEN

antennas. Assistant flight lead (#3) carried a pod mounting

ODD antennas. Their wingmen (#2 & #4) would carry at least

one pod on an outboard station and, by the end of 1967, on

both outboard pylons, one each EVEN and ODD, with the EVEN

pods mounted on the wings on the outside of the formation.

(Beginning in December 1966, Lead and three often carried an

AERO 3B-mounted AIM-B Sidewinder on the opposite outboard

pylon.)

‘Special’ Pods

The so-called ‘SPECIAL’ pods were a slight modification of the

original pods that used all four transmitters to block the SA-2

guidance (beacon) commands. Beginning in November 1967,

388th TFW Wild Weasel F-105Fs began using a configuration

of two pods per aircraft: one standard (sometimes called

‘NORMAL’) and one beacon configured (almost always marked

as ’SPECIAL’ on the side of the pod). Strike F-105D/Fs of the

355th and 388th TFWs adopted this practice the following

month. AN/ALQ-71s were used as SPECIAL pods prior to April

1968, but gradually gave way to the more powerful AN/ALQ87s for this task by July 1968.

By 1968 all aircraft using ECM pods were modified to provide

INFO Eduard - December 2019