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Red Shrimp

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Red Shrimp
Company typeMilitary electronic warfare system
IndustryDefense / Electronic countermeasures
Founded1950s
ProductsAirborne radar jammer


Template:Other uses

File:Avro Vulcan at Duxford Airshow 2012 (7977146095).jpg
XH558 performing at the 2012 airshow. The Red Shrimp units appear as two small black dots situated between the tailpipes of engines 3 and 4, near the top of the image.

Red Shrimp was an airborne, high-capacity radar jammer installed on both the Vulcan and Victor bombers. Its designation originated from the Rainbow Code system, while its formal title was ARI.18076, standing for Airborne Radio Installation.

The system utilized the carcinotron, a novel type of vacuum tube unveiled in 1953 by the French firm Thomson-CSF. This device generated microwave signals over a broad frequency range and could be tuned instantly by varying a single input voltage. It rapidly swept across all frequencies employed by hostile radars, cycling through their operational bands hundreds of times per second. The resulting interference cluttered the radar's plan position indicator, producing numerous false returns that effectively concealed the bomber.

Throughout its service life, Red Shrimp remained active within the V-bomber fleet. Although it was still installed during the Falklands War, it was regarded as outdated and was not deployed in combat operations.

Operation

Red Shrimp (also known as ARI 18076[1][lower-roman 1]) functioned as a broad-spectrum radar jammer operating within the 2.5–3 GHz frequency range.[3] At that time, this band was classified as part of the S band, spanning 1 GHz to 3 GHz; today it corresponds to the D and E frequency ranges. The core technology was a carcinotron or backward-wave oscillator (BWO) valve—a voltage-controlled oscillator capable of rapidly adjusting its frequency over a wide spectrum without any mechanical modifications. This enabled generation of a powerful jamming signal that could swiftly adapt to disrupt any radar frequency.

The primary jamming target was the Fan Song radar system, which served as the target acquisition radar for the S-75 Dvina surface-to-air missile (NATO reporting name: SA-2 Guideline). Meanwhile, the Blue Diver jammers were designed to counteract its associated UHF-band Knife Rest early warning radar.[4]

The Red Shrimp antenna assembly was compact, housed within a downward-facing hemispherical radome roughly 6 inches in diameter. Constructed from dielectric material and typically left unpainted in black or dark grey hues, it emitted signals in a conical beam with an aperture angle near 45°.[5] When bombers transitioned to extremely low-level flight profiles, this beam coverage correspondingly shrank to an area scarcely larger than the aircraft’s shadow on the ground.[5]

Valiant

The initial integration of Red Shrimp took place on a Valiant operated by the Bomber Command Development Unit.[6] This unit conducted trials using Valiant WP214 from late 1955.

By mid-1958, the Electronic Counter-Measures (ECM)[lower-roman 2] configuration destined for standard use across V bombers had been finalized. The components were housed within multiple sealed cylindrical containers weighing approximately 200 lbs each—the maximum manageable weight for maintenance personnel. These modules were installed in the aircraft’s tail section via an overhead trolley rail system. Cooling was provided through a water-glycol mixture circulated within a Vapour Cycle Cooling Pack (VCCP), supplemented by a sizable external air intake. To supply sufficient electrical power, an additional alternating current system was incorporated; rather than being driven by engines directly, this utilized an air-driven turbo-alternator unit.[7]

18 Squadron

Between 1958 and 1963, 18 Squadron functioned as a specialized electronic countermeasures (ECM) unit. It originated from the Valiant-equipped C flight of 199 Squadron, which had pioneered this role following the war.[lower-roman 3] These seven aircraft represented the sole Valiants outfitted for ECM purposes. Initially, their primary mission was to serve as training platforms for UK air defense forces by mimicking Soviet ECM threats. The concept of employing them operationally as ECM escorts for Valiant bomber formations emerged subsequently. Consequently, 18 Squadron also began participating in Quick Reaction Alert (QRA) scramble drills alongside Bomber Command’s main bomber units.[9]

The S-band jamming equipment installed on the 18 Squadron Valiants was the US-manufactured AN/APT-16A jammer, which relied on magnetron technology. This device was simpler and less advanced compared to frequency-agile carcinotron jammers. Trials with the Carpet 4 (ARI 18030, AN/APT-5) spot jammer took place on both Lincolns and the 18 Squadron Valiants; however, due to its unreliability and poor performance, it was ultimately abandoned.

A further constraint was the Valiant’s electrical system. The aircraft and the initial Vulcans featured a 112 V DC supply, whereas trial models had a more robust 240 V AC system. The DC electrical setup lacked sufficient power to operate active ECM devices such as Red Shrimp, restricting these planes to radar warning receivers and chaff dispensers only.[8] No upgrades were made to address this limitation because of the relatively brief operational lifespan of the Valiant.

Starting in 1958, 18 Squadron was stationed at RAF Finningley, South Yorkshire, alongside the Bomber Command Development Unit (BCDU). Sergeant Nick Prager, originally from Czechoslovakia and assigned to the BCDU’s ECM maintenance section, along with his wife Jana, provided photographs of ECM manual sets[lower-roman 4] to Czech intelligence. Prager was apprehended in 1971 after being exposed by defector Josef Frolík and received a twelve-year sentence for espionage.[10] From 1961 onward, 230 OCU, responsible for Vulcan crew training, was also located at Finningley.

With the recognition that bombers would need to penetrate defenses at low altitude individually rather than in formations, each aircraft required its own ECM suite. Although 18 Squadron continued development and training activities for some time, these functions could be effectively carried out by less complex platforms like English Electric Canberras instead of Valiants. As a result, the squadron was disbanded in 1963.[11]

Vulcan B.1

The initial Vulcan B.1 model featured a relatively basic ECM configuration that primarily included chaff dispensers and the Orange Putter tail warning system inherited from Canberra and Valiant aircraft.[12]

Additional ECM equipment could be installed along the bomb bay sidewalls in up to nine modular containers. These packages comprised devices such as the Green Palm VHF voice communications jammer, the carcinotron-based Indigo Bracket, and the Red Carpet X-band[lower-roman 5] radar jammer.[12] Each system was designed for self-contained operation requiring minimal airframe modification. At this stage, the Olympus 104 engines lacked sufficient electrical output to support such ECM suites independently; therefore, an internal ram air turbine was incorporated similar to that fitted on trial Valiant WP214. This Turbo Alternator TGA 30 Mk 1 unit was housed internally and powered by an air intake positioned adjacent to the port engine inlet.[13]

Vulcan B.2

File:Vulcan B2 XJ784 at Bagotville.jpg
Extended ECM tail

Both the Vulcan B.2 and B.1A featured an elongated rear fuselage that extended into a more rounded tailcone.[lower-roman 6] The tail end was redesigned to include a hemispherical radome housing the Red Steer tail-warning radar, replacing the pointed cone found on the B.1 models. On the starboard side, a substantial rectangular duct served as the cooling air intake for the condenser of the VCCP system. The braking parachute was housed beneath a hatch on the upper surface, now visible as an external bulge.[12] Inside this tail section, nine sealed and pressurized ECM equipment drums were arranged in two rows, accessible through bottom hatches.[3]

The Red Shrimp antennae were mounted on panels installed between engines, typically between engines 3 and 4 on the starboard side. Some aircraft carried three antennae on one side, while others had two on one side and one on the opposite side. Early versions of Blue Diver employed a blade aerial; later models transitioned to wingtip-mounted aerials.[3] [14]

Name Function [1][14]
Green Palm ARI 18074 VHF Communications Jammer subsequently replaced by ARI 18146
Blue Diver ARI 18075 UHF Jammer operating in the B-band
Red Shrimp ARI 18076 S-Band Jammer (~3 GHz)
Red Steer ARI 5919 Tail warning radar
Blue Saga ARI 18105 Passive Radar Warning Receiver (RWR) later superseded by ARI 18228

Vulcan B.1A

File:Avro Vulcan underside engine detail, Midland Air Museum. (12758207333).jpg
Counterpoise panel between engines displaying two Red Shrimp hemispheres

The Vulcan B.1A represented a transitional modification converted from existing B.1 aircraft.[15] ECM capabilities were integral to the new B.2 variant featuring extended Phase 2C wings; although there was significant urgency for delivering these new B.2s—with the first arriving before any B.1As—the simpler conversion process allowed thirty ECM-equipped B.1As to enter service more rapidly than producing an equivalent number of new B.2s.[16]

Low-level

Following the conclusion of the Nassau Agreement in late 1962, Britain's foremost nuclear deterrent shifted to the Royal Navy's submarine-launched Polaris missile.[lower-roman 7] This strategic shift within the nuclear triad, combined with the enhanced effectiveness of Soviet high-altitude surface-to-air missiles,[lower-roman 8] prompted a reorientation of V-bomber tactics from high-altitude penetration to a high-low-high attack profile emphasizing low-level ingress. V-bomber crews had previously trained to evade early threats like the SA-1 Guild and SA-2 Guideline missile systems concentrated around Moscow by employing jamming techniques alongside Green Satin radar and NBS maneuvers involving frequent course adjustments to disrupt missile lock-on.[17]

By 1963, deployment of the Soviet SA-3 Goa missile system equipped with its Low Blow radar had commenced.[3] Although countermeasures like Red Shrimp remained effective against SA-3, its mobility and widespread deployment—including border regions beyond Moscow—necessitated attack altitudes below its operational ceiling for successful engagement.[17][lower-roman 9] Consequently, strike profiles required flying beneath approximately 500 feet altitude, often even lower when traversing hilly terrain.[17][lower-roman 10]

Starting in Spring 1963 for B.1 models and from 1964 for B.2s, these aircraft were reassigned to low-level attack roles.[18] A visible indication of this operational shift was Mod.1877—repainting aircraft from their previous anti-flash white to a two-tone camouflage pattern.[19]

Despite this doctrinal change in mission profile, there were no modifications made to Vulcan ECM systems at that time. Over the following two decades, development stagnated and effectiveness declined progressively.[3] While situational awareness regarding threats remained adequate, countermeasure capability diminished significantly.[3] Notably, Red Shrimp jammers were installed underneath the aircraft facing downward; at low altitude these signals were obstructed by terrain features used for concealment by the aircraft itself, drastically limiting their effective coverage area.[3] One significant upgrade implemented from 1966 onwards was the addition of a terrain-following radar (TFR), identifiable by a small thimble-shaped radome mounted on the nose.[20]

Falklands Conflict

In the course of the Falklands War and Operation Black Buck, the Vulcan bomber along with its electronic countermeasure (ECM) systems were regarded as outdated.[21] While systems like Green Palm and Blue Diver retained some operational value, Red Shrimp was largely viewed with diminished confidence.[22] Red Shrimp functioned as a barrage noise jammer; however, two decades of counter-countermeasure advancements had rendered it vulnerable. The expected Argentine defenses, including the Super Fledermaus, Skyguard anti-aircraft guns, and Roland missiles, were anticipated to effectively counteract it, particularly at close distances. Consequently, Vulcans were equipped with American-built AN/ALQ-101D deflection jammer pods and underwent training at the Spadeadam range to operate them.[23] As a result, the Black Buck sorties did not employ Red Shrimp and instead depended on the Dash 10 pods.[24]

Victor

The twenty-four B.1A variants of the Victor bomber featured an electronic warfare suite identical to that of the Vulcan. This included systems such as Red Steer, Blue Saga, Green Palm, Blue Diver, Red Shrimp, along with chaff dispensers.[25]

TSR2

Initial design assessments during the early phases of the TSR2 program recommended integrating an X-band carcinotron jammer like Red Shrimp or at least reserving space for one within the aircraft. However, financial limitations resulted in this feature being excluded from official specifications. At the time of TSR2’s cancellation, Naval / Air Staff Target 830—which addressed future jamming capabilities—was still under review. It was expected that TSR2 would employ externally mounted equipment on pylons if required by mission parameters.[26]

Operation

The control interface for Red Shrimp consisted of Type 9422 control units that were straightforward in design. Operators could simply activate or deactivate the system, toggle between two automatic modes, and monitor operational parameters such as performance metrics, electrical current consumption, and temperature levels. This control panel was situated on a small console at the lower desk used by the Air Electronics Officer (AEO), positioned on the right side of the rear cockpit facing aft.[27][28]

See also

References

  1. ↑ ARI: Airborne Radio Installation[2]
  2. ↑ Known as Radar Counter Measures (RCM) during that period[6]
  3. ↑ WP213, WZ365, WZ372, WP212, WP215, WP216 & WP211, listed in sequence of conversion at RAF Watton [8]
  4. ↑ Blue Diver and Red Steer were notably impacted systems.
  5. ↑ X band frequency range: 6,200 – 10,900 MHz according to NATO designations; historically this band has been subdivided into H band and I band, with some overlapping usage of “X band.” See X band.
  6. ↑ While the initial B.1, XH533, did not incorporate this design, the first fully equipped B.2, XH534, did.
  7. ↑ The transition to Polaris took several years and was not completed until 1969.
  8. ↑ Illustrated by the 1960 shootdown of Gary Powers' U-2 aircraft.
  9. ↑ Surface-to-air missiles have an optimal engagement altitude range; effectiveness diminishes significantly above or below this band.
  10. ↑ Unlike radar horizon limitations based on line-of-sight distance, missile effective altitude depends on relative height from its launch position.
  1. ↑ 1.0 1.1 {{Cite web  |title=Radar & EW in the RAF  |author=Prof. Steve Roberts  |publisher=RAF Cranfield  |year =2014  |page =24  |url=https://www.cambridgewireless.co.uk/media/uploads/resources/Heritage%20Group/16.10.15/Heritage-16.10.15-SelexES-Steve_Roberts.pdf  |archive-url=https://web.archive.org/web/20231007211404/https://www.cambridgewireless.co.uk/media/uploads/resources/Heritage%20Group/16.10.15/Heritage-16.10.15-SelexES-Steve_Roberts.pdf  |archive-date =2023-10-07  |url-status =dead }}
  2. ↑ Lua error in Module:Citation/CS1/Configuration at line 2123: attempt to index field '?' (a nil value).
  3. ↑ 3.0 3.1 3.2 3.3 3.4 3.5 3.6 {{Cite journal  |title=Early Warning During the V-Force Era  |journal=Royal Air Force Historical Society  |author=Wg Cdr Rod Powell  |pages=8–11  |date=Winter 2005  |via=X M655  |url=https://xm655.com/blog/wp-content/uploads/2017/05/Newsletter-14-Winter-2005.pdf }}
  4. ↑ 4.0 4.1 Lua error in Module:Citation/CS1/Configuration at line 2123: attempt to index field '?' (a nil value).
  5. ↑ 5.0 5.1 RAF Historical Society, 28, p. 77.
  6. ↑ 6.0 6.1 Lua error in Module:Citation/CS1/Configuration at line 2123: attempt to index field '?' (a nil value).
  7. ↑ Brookes (2012), pp. 45–46.
  8. ↑ 8.0 8.1 Brookes (2012), p. 46.
  9. ↑ Brookes (2012), pp. 45–48.
  10. ↑ {{Cite book  |title =Traitor: British Double Agents1930-80  |first =John Frayn  |last =Turner  |publisher =Bloomsbury Publishing  |year =2012  |isbn =978-1780967295  |url =https://books.google.com/books?id=uonvCwAAQBAJ&pg =PT132 }}
  11. ↑ RAF Historical Society, 28, p. 69.
  12. ↑ 12.0 12.1 12.2 Lua error in Module:Citation/CS1/Configuration at line 2123: attempt to index field '?' (a nil value).
  13. ↑ Darling (2007), pp. 35, 56.
  14. ↑ 14.0 14.1 Lua error in Module:Citation/CS1/Configuration at line 2123: attempt to index field '?' (a nil value).
  15. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named Dancey, 96
  16. ↑ Dancey (2014), p. 100.
  17. ↑ 17.0 17.1 17.2 Lua error in Module:Citation/CS1/Configuration at line 2123: attempt to index field '?' (a nil value).
  18. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named Haynes, Vulcan
  19. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named Darling
  20. ↑ Lua error in Module:Citation/CS1/Configuration at line 2123: attempt to index field '?' (a nil value).
  21. ↑ Lua error in Module:Citation/CS1/Configuration at line 2123: attempt to index field '?' (a nil value).
  22. ↑ White (2007), p. 199.
  23. ↑ White (2007), p. 211.
  24. ↑ White (2007), p. 331.
  25. ↑ Lua error in Module:Citation/CS1/Configuration at line 2123: attempt to index field '?' (a nil value).
  26. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named Brookes, 2017, TSR2 ECM
  27. ↑ Haynes, Vulcan, pp. 106, 108, 110–111.
  28. ↑ {{Cite web  |title =Vulcan Cockpit (XL426) - In Detail  |date =1 October2009  |website =UK Airshow Review  |url =https://forums.airshows.co.uk/viewtopic.php?f=10&t =16451 }}

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