Radar Passive Warning
Systems
(Explanation/Technical History)

This page was last updated:- 7th November 2004
This article has been written with the technical collaboration of: John Robertson
Electronic Engineering Technician - 12, 15, Squadron, 237 OCU and Buccaneer/Jaguar Maintenance School.

Radar Passive Warning System pods - fitted to wing leading edge It can be seen from photographic evidence that, throughout the service life of the Buccaneer, 'Pods' were often fitted to the leading edge of both wings. However, there is some confusion between publications and articles as to exactly what these were and why they appear to be fitted to some aircraft and not others.

Various descriptions for them are: VHF Pods, Homing Pods and also Radar Warning Pods.

Violet Picture - Radio Homing System

In respect of the Buccaneer's Radio Homing system, this was called Violet Picture. The aerials used for this 'Location System' are in fact the two small 'chin' aerials positioned close together under the nose, just in front of the nosewheel bay. A typical use for this system was for the location of an 'In-Flight' Refuelling tanker aircraft.		 'Violet Picture' - Radio Homing System aerials

Radar Passive Warning Systems - Leading-Edge Wing Pods

These were actually used for various 'Radar Passive Warning' systems. Over the thirty-odd years that they were fitted to Buccaneers, these pods went through several modifications as the number of bandwidths were increased for S Band and S/X Band Wideband Homer (WBH) and subsequently Sky Guardian 200 Radar Warning Receiver.
1961-1971 — S.Mk.1 and early S.Mk.2 Buccaneers up to 1972 were fitted with 'Airborne Radar Installation' S Band WBH - ARI 18154. 'S Band' covers the frequencies used by 'Ship-Borne' and many airfield radars. It was used for locating ships and, on attack runs, was used to ensure the aircraft were keeping under the radar envelope. These early pods were round in cross section.
1972-1975 — In 1972 S/X Band WBH - ARI 18216 - was introduced. 'X Band' covered early airborne 'Monopulse' radars. To accommodate the additional receivers larger pods were fitted. These pods were deeper and more flat-sided in cross-section. Integral with this was the installation of equipment within the cockpit containing an 'Audio Oscillator' to enable the navigator to match the tone emitted to the 'Pulse Repetition Frequency' of the radar transmitter and thereby help identify the radar type and whether it was a NATO 'Friendly' vessel or Warsaw Pact 'Enemy' vessel.

Unlike our American cousins, the British like to ensure that they are actually shooting at the enemy! To this end, the identification was to check that, before spoiling someone's day with an 'Anti-Radar' Martel missile or other weapons, the target radar emissions detected were in fact form the 'Topsail' on a Kiev, Kara or Kresta vessel rather than a NATO ally.
The photograph on the right shows the S/X Band WBH equipment installation within the observer/navigator's rear cockpit (Port):

 ( 1 ) The Wideband Homer Indicator was fitted with a tube to shroud the small Cathode Ray Tube (CRT). This showed bearing of radar transmissions up to 60-degree port or starboard ahead of the aircraft. When WBH was upgraded from S Band to S/X Band three addition boxes were fitted in the cockpit.

 ( 2 ) The box immediately above the indicator contains the Frequency Oscillator.

 ( 3 ) The box beside it selects between S and X Bands.
( 4 ) The box immediately beneath the fire extinguisher was commonly called ‘the cheese’ because of its wedge shape. The cheese contained potentiometers which were adjusted by radar tradesmen to balance signals from receivers in the port and starboard wing pods.

Wideband Homer was used until new equipment was introduced by modification from 1975 onwards.


Pulse Warning & Homing System

1975-1987 — The new equipment installed was called Pulse Warning & Homing System but more commonly known as Radar Warning Receiver (RWR). The external indications of RWR were the fibreglass covers for the aerials, fore and aft on the tailplane bullet. RWR introduced additional 'Bandwidths' including those used by 'Anti-Aircraft Missile' installations and Pulsed Doppler Radar - used on some interceptors. Additionally RWR gave 360-degree coverage instead of 'Forward-Only' as on Wideband Homer (WBH).

 Radar Warning Receiver - fore and aft on the tailplane bullet
Following the fitment of RWR to 15 squadron's Buccaneers at RAFG Laarbruch, West Germany in 1975, the aircrew on returning from their first mission remarked that: "Flying above 1000ft they could detect the East German missile sites locking on to them and handing over to the next site as they flew along the border". It was something of an eye opener.
Instrument Landing System - 'localiser' aerial The introduction of RWR meant WBH was largely redundant. The pods and other equipment were then removed when the aircraft went in for Minor Servicing.

However 12 Squadron retained WBH for some time because it gave a greater detection range for shipping strike missions.

Another modification carried out at the same time was the installation of Instrument Landing System (ILS), identifiable by the 'Localiser' aerials on either side of the fin.

Avionics Upgrade Programme

In February 1985 an 'Avionics Update Programme' was initiated for the Buccaneer under the designation ASR 1012. This was to incorporate the following improvements: Ferranti FIN 1063 INS refinement to the Blue Parrot radar system, 'Inertial Navigational', new Plessey ASR 899 radio, modernisation ARI 18228 ECM/ESM Sky Guardian 200 Radar Warning Receiver, plus the Sea Eagle 'Fire & Forget' Anti-Ship Missile system, full Sidewinder AIM-9G & AIM-9L 'Air-to-Air' missile capability plus the additional 'Self-Defence' measures with the inclusion of Tracor AN/ALE-40 'Chaff/Flare' dispensers. Also the ability to operate in a 'Nuclear, Biological & Chemical' (NBC) environment following alterations within the cockpit to permit the aircrew full AR5 clothing.

This upgrade got underway during 1986 and involved a total of 42 Buccaneer S.Mk.2B's from RAF Lossiemouth. Because this was a reasonably major update, it was necessary to release the Buccaneers in batches to BAe Woodford for the modifications.

208 Sqn. was the first to receive the upgraded aircraft, followed by 12 Sqn. and finally 237 OCU. In 1989 the 42nd and final 'AUP' Buccaneer returned to active service at RAF Lossiemouth.
Sky Guardian 200 Radar Warning Receiver
1987 Onwards — Sky Guardian 200 Radar Warning Receiver introduced more bandwidths and the 'E/J Receivers' were installed in the old S/X Wideband Homer pods which were re-fitted to the wing leading edges. Sky Guardian pod


Source - John Robertson (Electronic Engineering Technician)
12, 15, Squadron, 237 OCU and Buccaneer/Jaguar Maintenance School.
Additional Info. - Buccaneer: The story of the last all-British strike aircraft (Tim Laming)
The Buccaneers (Air Commodore Graham Pitchfork)
Wings of Fame - volume 14 (Aerospace Publishing Ltd)
RAF Buccaneer (Peter Foster)
(see Reference Library page for full details)
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