The evolution of airborne electronic warfare systems.
Hide-and-Seek is Becoming a Very Difficult Game to Play
Many aspects of airborne electronic warfare had their origins in WWII, but in the early post-war period there was a hiatus, until the first American jamming pod suitable for tactical fighters was delivered in 1956. The escalation of the Vietnam War at the end of 1964 brought a sudden demand for modern EW equipment, primarily because of the introduction of SA-2 batteries around Hanoi in early 1965. To reduce the SAM threat, US aircraft were equipped with radar warning receivers (RWRs), and some later had jammer pods and chaff-dispensers. Strikes were supported by EB-66 jamming aircraft and F-4 "chaff-bombers", as well as by F-100F, F-4C and F-105G Wild Weasels using anti-radiation missiles (ARMs).
Other nations lagged behind. When British forces went to the South Atlantic in 1982, Harriers had RWRs but lacked chaff dispensers and jammers. Anti-radar strikes were left to the Vulcan, using Texas Instruments AGM-45 Shrikes, and Westinghouse ALQ-101 jammer pods. The Israelis were meanwhile using electronic warfare on a large scale in the Lebanon, attacking Syrian SAM sites with virtual impunity. The same applied to US strikes against Libya in 1986, which involved the Texas Instruments AGM-88 HARM and Shrike, and support jamming by EF-111As and EA-6Bs.
Before reviewing the main types of EW equipment on a country-by-country basis, it may be useful to outline the principal lines of current EW development.
The term ESM (Electronic Support Measures) is generally used to indicate the passive identification and location of emitters, using relatively sophisticated equipment, possibly with data-recording facilities. A simpler form of passive equipment is the radar warning receiver (RWR), which indicates to the pilot the type of radiation to which his aircraft is exposed, the relative bearing of the transmitter and possibly its range and operating mode. In US terminology RWRs come in the AN/ALR series, e.g., the Magnavox ALR-50 that is fitted to several types of US Navy aircraft.
In essence, a number of small antennae are linked to a bank of receivers, each tuned to a consecutive slice of the waveband, thus allowing the radar type to be identified. Its bearing and approximate range may be established by comparing the signals received by the different antennae.
Adequate threat warning may be provided by a simple crystal video receiver, but increased sensitivity can be achieved with superheterodyne receivers. However, their greater range results in more data, and thus calls for a more capable threat processor. One example of such equipment is the Loral ALR-56 series of RWR with programmable processor used on the F-15.
Threat warning systems are currently being extended to cover different bands, such as lasers, IR (for missile launch warning), millimetre-wave radar and even ultraviolet. Warning systems are also being linked directly to countermeasures, and in some cases the two are being developed as an integrated system.
Laser warning systems are receiving considerable emphasis for several reasons. Most tanks now have laser rangers, and many air defence guns are being equipped with automatic electro-optical tracking and laser ranging. In addition, laser guidance is gaining in popularity for SAMs, as illustrated by the Oerlikon/Martin Marietta ADATS. Laser warning equipment manufacturers include Elisra, Ferranti, Marconi Defence Systems, MBB, Perkin-Elmer and Thomson-CSF.
Direct linking of the RWR to countermeasures is illustrated by the case of the F-15, in which the Loral ALR-56C controls the Northrop ALQ-135B jammer and the Tracor ALE-45 dispenser.
Examples of fully integrated EW systems for tactical aircraft include the Marconi/Northrop Zeus for the Harrier GR5/7 and the Mirage 2000's ICMS, in which Thomson-CSF cooperated with AMD-BA, ESD and Matra. Looking further to the future, INEWS is the integrated EW system for the USAF F-22/23 Advanced Tactical Fighter, and will include countermeasures against not only radar but also IR and laser threats.
Airborne radar countermeasures traditionally take the form of stand-off and stand-in (escort) jamming, but many tactical aircraft can now carry (and in some cases house) their own defensive jamming equipment. Jamming may be performed by a transmitter that either swamps the enemy transmitter (i.e., noise or brute-force jamming) or produces misleading information (deception jamming), creating false targets or breaking radar tracking.
Enemy radars and radar-guided missiles may also be defeated by reflective clouds of chaff, i.e., aluminium foil strips, or aluminium-coated plastic strands or glass fibres. Chaff is normally carried in pylon-mounted launchers or "scabs" attached to the airframe or pylons, though in some cases the dispenser is mounted internally. For example, the AMX currently has four internal dispensers in the rear fuselage, and the MB-339C has dispensers in wing bays adjacent to the mainwheels. It is noteworthy that the MiG-29 has overwing dispensers firing upwards to prolong the dwell-time of the chaff cloud at a suitable height.
A comparatively new development is the "smart" threat-adaptive dispenser, which ejects a chaff or flare pattern tailored to the nature of the threat, as determined by the threat-warning system. One of the first such equipment is the Tracor ALE-45 for the F-15, which will be followed by the joint USAF/USN ALE-47.
The development of mini-jammers has largely been pioneered by the US Navy, using standard dispensers. These expendables are battery-operated, and may function either as noise jammers or deception repeaters. Current active expendables are exemplified by the Brunswick Corp. RFED (Radio Frequency Expendable Decoy) and the Sanders POET (Primed Oscillator Expendable Transponder), which entered service with the US Navy around 1980. In September 1987 the Navy awarded a full-scale development contract to Texas Instruments for a new generation designated GEN-X (Generic Electronic Expendable), providing broader band coverage than POET.
Although GEN-X will be relatively inexpensive, operating costs may in principle be reduced and effectiveness increased by the use of larger semi-expendables or towed decoys. These can be powered by and controlled from the parent aircraft and jettisoned at the end of the mission. Such decoys are being developed under the US Navy AAED (Advanced Airborne Expendable Decoy) programme. Whereas GEN-X has an overall dimension of only 15 cm, the AAED may be six times as long and correspondingly more capable. Work is also proceeding on a powered derivative that would fly ahead of the aircraft during an attack on a surface target.
In this context it may be noted that the Israelis used the Brunswick Corp. Samson drone as a decoy in the Lebanon in 1982, and that the US Navy has purchased an improved version. Samson is thought to use Luneberg lenses to give it a full-size radar signature, although a second variant is employed purely as a chaff-dispenser. It may also be noted that the USAF has a programme named Faitour to develop a multispectral decoy to deal not only with radars but also with IR and EO threats.
European work in this field is less publicised, but it is known that Britain's EEV Magnetrons has produced prototype travelling wave tube amplifiers (TWTAs) specifically for decoy applications. It is also known that the Eurodass (Marconi/Elettronica/Ensa/Inisel) consortium proposal for EFA includes an ECM pod with up to three reels of wire with <<dumb>> transmitters at the end, the sophisticated jamming equipment being retained in the aircraft. Reports of this proposal also refer to the <<smart>> dispensing of IR flares, to such effect that a single flare will be sufficient to decoy an IR-homing missile.
The use of IR flares is based on the fact that a simple IR missile will switch lock from the aircraft to a close high-powered IR source. However, the effectiveness of such flares is limited by the number that can be carried and by the sophistication of some new IR-guided weapons.
If an aircraft may be subjected to IR missile attack at any stage of its flight, then (depending on the reliability of its threat warning system) a different type of IRCM may be required. Fortunately, most existing IR homers rely for their guidance on <<chopping>> the incoming IR energy. This is done by means of a rotating disc with specially-shaped transparent slots. The transmission thus becomes a series of pulses, the nature of which indicates target position relative to missile axis. If an IRCM equipment on the target can transmit pulses of a suitable frequency, then the missile will generate false guidance demands.
The leaders in this type of IRCM are Northrop, Loral and Sanders Associates. Northrop is believed to use electrical modulation to produce the pulses, and its production series began with the AAQ-4 used in the EB-66 in Vietnam. The AAQ-8 supersonic pod (also based on a vistal caesium source) was later fitted to some F-4s in the same war.
The Loral ALQ-123 IRCM pod is used on US Navy A-6s and A-7s, and reportedly on E1 A1 airliners. One of the first public showings of IRCM occurred at Le Bourget in 1983, when Sanders pods were fitted to the pylons of the B-747 Shuttle transporter. One of the most widely-used IRCM systems is the Sanders ALQ-144, which is fitted to many US Army helicopters and some British Army helicopters in Northern Ireland. Over 1000 have been produced. Current Northrop equipment is exemplified by the MIRTS (Modular IR Transmitting Set), used on some examples of the A300, B-707, B-747, DC-8, DC-10, Mirage Fl, Northrop F-5, Falcon 20, C-130 and BAe 125.
Although IRCM is currently effective against most IR homers, it can in principle be defeated by missiles with staring arrays of cells, just as flares can be defeated by the missile rejecting sources that also produce visible light.
On the subject of IR, mention may be made of missile launch warning systems that detect the flash of the weapon firing. This is presumably the system used for the AAR-34 tail-warning system for the F-111 and the new AAR-44 for USAF C-130s, an equipment also produced by Cincinatti Electronics. The Sanders ALQ-156 uses pulse-Doppler radar to detect approaching missiles by measuring closure rates and other ballistic parameters, and activates counter-measures. Its first application is the US Army CH-47.
Turning to defence suppression, the concept of loitering anti-radar drones is gaining in popularity. The most important is probably the Northrop Tacit Rainbow (AGM-136A), which can be either ground- or air-launched. Significant ARM developments include the Matra STAR (Supersonic Tactical Anti-Radar) missile and the BAe ALARM, which scans for its target while descending on a parachute.
To counter such devices, some work is being done on equipment to decoy ARMs away from radars. The decoy is connected to the real radar, and emits sidelobes from a distance of several hundred meters. The principal US companies involved are LTV's Sierra Research division, ITT Gilfillan, and the Ayden Corp.
The following notes outline some of the principal types of airborne EW equipment now available or under development, with the country of origin listed in alphabetical order.
ENAER has an electronics division, which developed the Caiquen II RWR for the Hunter, the Caiquen III for the Mirage, and the associated Eclipse chaff/flare dispenser system. The company has also developed the ITATA ELINT system for radar detection, location and analysis, a system suited to installation in twin turboprops and larger aircraft.
Etienne Lacroix produces a range of IR flares and chaff cartridges, and a chaff rocket head that spreads its load up to 10 km ahead of the aircraft. At Farnborough last year the company showed the Type 885 EO flash cartridge, intended for use from the Matra SYCOMOR launcher, to make EO/FLIR trackers lose lock. In the context of decoy dispensers, mention must also be made of Alkan's range of dispensing pods, such as the Type 530 and 531.
Electronique Serge Dassault (ESD) has been active in EW for over 30 years. The company's present range includes the ABD 2000 internally-mounted detector-jammer for the Mirage 2000, an equipment that forms part of the integrated ICMS suite jointly developed with AMD-BA, Thomson-CSF and Matra. New ESD developments include the CAMEL airborne decoy. The company is also working with Thomson-CSF on an integrated EW system for the Rafale D. The Barax deception jammer for the Mirage F1 has been exported to Spain, and ESD has proposed - in conjunction with Germany's LITEF - the HERALD (Helicopter Equipment for Radar and Laser Detection) for the Franco-German attack helicopter programme.
Matra has achieved considerable success in marketing the PHIMAT cartridge dispenser, and has now developed a range of more advanced dispensers. These include the SYCOMOR for the Mirage F1, the CORAIL for the F1CR, Mirage 2000, Super Etendard, ATL2 and Transall, the SPIRALE internally-mounted dispenser for the Mirage 2000 and the SAPHIR for helicopters.
Thomson-CSF is a highly prolific company, and it is possible here to mention only a few of the products of its RCM division. Its in-service RWR range includes the Type BF for early Mirages, the TMV008H for helicopters, the DR2000 Dalia Mk. 2 for the EMB-111 and Sea King and the DR3000 and DR4000 for maritime patrol aircraft. The Serval RWR is used on the Mirage 2000, and from this has been developed the much smaller and lighter Sherloc, which will also be applicable to helicopters. The ARAR-13 is the RWR for the ATL2.
From the early Remora self-protection jammer Thomson-CSF has developed the Barem pod, which is linked with the Sherloc RWR to form the MSPS (Modular Self-Protection System) for the Mirage 2000. Derived from the ICMS (Integrated Counter-Measures System) for the Mirage 2000, the SPICS equipment is intended for larger aircraft. For escort jamming, the company produces the Caiman pod, from which has now been developed the Basilisk, capable of dealing with up to 30 radars simultaneously.
Thomson-CSF equipment for the tactical ELINT mission includes the Syrel pod for the Mirage F1 and Puma, and the new ASTAC, which can handle up to 20 radars at once and (like Syrel) has a UHF data-link to the ground. Strategic ESM equipment for large transport aircraft is exemplified by the Elisa, the Sarigue used in the DC-8 and the Gabriel used in the Transall. Recent developments include the Adelie laser warning receiver, which has a detection range of 10 km, and the Miriade mm-wave detector, which is likewise aimed at helicopter applications.
* Germany (West)
German work in the EW field is less well-known, due to marketing restrictions, although AEG-Telefunken is known to be responsible for the Cerebus series of jammer pods for the Tornado. MBB has a laser warning receiver designated COLDS, for which Tracor has the US licence.
Elisra markets a range of threat warning and ESM/ELINT systems. For helicopters, the basic RWR system is the SPS-20, which with an additional receiver and the LWS-20 laser warning system becomes the SPS-65. For the combat aircraft upgrade market Elisra offers the basic SPS-200, which has sold in large numbers, or the improved SPS-1000. The top of the range is the SPS-2000, aimed at the F-16 market. All of these systems may be linked to an IMI cartridge dispenser, the MPMN-36(V), and a jammer.
Elta produces the EL/L-8202 jammer pod and the EL-8230 internal self-protection jammer. There have also been references to the EL/M-2150 missile launch warning system. The Rafael Rattler jammer has been developed for airborne, sea- and land-based use, and can deal with up to three radars simultaneously.
Elettronica produces the ELT/553 self-protection jammer for the AMX, the ELT/554 lightweight deception jammer for the A.129 and the RWR and internal ECM system for the Tornado ECR. The ELT/158 RWR and ELT/558 self-protection jammer are aimed at the export version of the Mirage 2000. The ELT/555 is a supersonic jammer pod, powered by a ram air turbine in the nose, and the Aries is an ELINT and support jamming suite intended for business jet installations. Selenia EW products include the SL/ALQ-234 self-defence jammer pod and the RQH-5(V) family of modular ESM/ELINT sensors, among which the SL/ALR-730 for the Italian Navy Atlantic, the SL/ALR-735 for the Italian Navy EH-101, the SL/ALR-743 for an unspecified foreign fighter and the SL/ALR-730 for an export AB-212.
Ericsson Radio Systems offers the Erijammer series of ECM pods. The Type A100 is used for the Swedish Air Force for fire-control radar jamming and radar operator training, and the Type 200 is the SAF's standard tactical jammer for the Viggen. The Erijammer B100 is under development as a training pod for surveillance radar jamming, and the Type 300 is a self-protection pod for the JAS39.
Philips Elektronikindustrier AB (PEAB) has been making airborne dispensers since the late 1950s. The BOZ 3 is a chaff dispenser used for EW training, mounted on SAF Lansens and Learjets. The BOZ 100 series is the current chaff/flare dispenser pod used on the Tornado and French Jaguars. The domestic equivalent for the Viggen is designated BOX 9. The BOP 300 is a new generation of internal and scab-mounted dispensers, evidently intended for the JAS39 and exports. The other member of this computerised BO 300 family is the helicopter version, the BOH 300.
In addition, SATT Electronics produces the AR.765 RWR for the AB.206A, the AQ.31 jammer pod for the Viggen and the AQ.800 jammer pod for EW training. SRA Communications reportedly produces the Type KA jammer pod for the Viggen and the Type 2000 jammer for subsonic aircraft.
* United Kingdom
British Aerospace is developing the ALARM defence suppression weapon and is marketing an IRCM equipment for helicopters. The emission is produced by a graphite radiating element in a sapphire envelope and pulsed by means of shutters.
Ferranti's AWARE-3 (Advanced Warning of Active Radar Emissions) has recently been selected for British Army Lynx and Gazelle helicopters. Typical of advanced RWRs, AWARE-3 identifies the emitter by comparing it with a stored threat library, and shows its type, bearing and range on a PPI (Plan Position Indicator) display.
Marconi Defence Systems (MDSL) EW Equipment protects all combat aircraft of the RAF and Royal Navy. The company's products include the RHWR (Radar Homing and Warning Receiver) and Sky Shadow jammer pod for Tornado, the Zeus combined RWR and jammer for the Harrier GR5/7 and Tornado mid-life update and the Hermes and Sky Guardian ESM families of equipment.
The Philips Group's MEL subsidiary is responsible for the ESM system of the Nimrod, but the company is mainly concerned with naval ESM equipment (which is fitted to all Royal Navy ships) and to a lesser extent with naval jammers.
Plessey Avionics EW equipment includes the Missile Approach Warner (MAW) for the Harrier GR5/7, which is based on a pulse-Doppler radar. A modified version has been developed for the Tornado. Plessey also makes a laser warning receiver for helicopters and the Kester RWR, which is aimed at the market gap between simple crystal video RWRs and the more expensive superheterodyne receivers.
Racal Avionics' EW range includes the Prophet lightweight RWR, which has been selected for the BAe Hawk 100/200, the Kestrel ESM for the EH-101 and Royal Danish Navy Lynxes, and the MIR-2 ESM for Royal Navy Lynxes and Sea Kings, and RAF C-130s.
Britain's leading supplier of chaff/flare dispensers and cartridges is ML Wallop Defence Systems Ltd. Its products include the Evade dispenser system for fixed- and rotary-wing aircraft, and a range of chaff and IR decoy cartridges.
* United States
The multiplicity of American EW equipments has become something of a national scandal, with over 60 systems now flying on USAF and Navy aircraft alone. In the following summary it is possible to mention only the principal companies involved, and some of their products.
The Brunswick Corporation is perhaps best-known in the electronic warfare context for its work on active expendables such as the RFED and its drone decoys, which are also built by Israel Military Industries. The original Samson decoy has been used operationally in the Middle East, and TALD (Tactical Air-Launched Decoy) uses later technology and offers improved performance and payload. The TALD is used by the US Navy to protect its attack aircraft.
Cincinatti Electronics produces the AAR-34 and -44 tail warning systems. Eaton-AIL is responsible for the ALQ-161 defensive avionics system of the B-1B and the ALR-77 ESM system for the P-3C. General Instrument manufactures the ALR-66(VE) RWR recently ordered for RAF transports and tankers, and the ALR-87, which is made by the Dalmo Victor division. The company's Government Systems division is responsible for the ALR-80(V), which is described as an advanced version of the widely-used ALR-66(V), and the only RWR providing the user with complete and independent control of the system programming and maintenance.
Goodyear makes various cartridge dispensers, including the ALE-39 fitted to most US Navy aircraft. ITT Avionics has developed a series of jammers, notably the ALQ-129 used on Navy F-4s, A-7s and F-14s, and the ALQ-136 used to protect US Army helicopters and light aircraft against the ZSU-23-4. The company is also responsible for the ALQ-172 jammer upgrade for the B-52 and the MC-130E/H, and (with Westinghouse) for the ALQ-165 ASPJ (Airborne Self-Protection Jammer) for the F-16C, F-14D, AV-8B and F/A-18.
The Applied Technology division of Litton is claimed to be the world's leading producer of airborne RWRs. Its range includes the ALR-67 and -45F for front-line US Navy aircraft, the ALR-69 and -74 for the USAF and the ALR-68A(V)-2 for German Air Force F-4s.
Loral makes the ALR-56 RWR for the F-15, the ALQ-123 IRCM pod for Navy aircraft, the ALQ-157 IRCM equipment for Navy helicopters and the ALQ-178 Rapport warning, jammer and expendables system for some export F-16s. The company's ALR-56M advanced RWR for the F-16 is reportedly the USAF's biggest ever EW programme.
Lundy produces a series of cartridge dispensers, including the ALE-29A for Navy aircraft and the more recent ALE-43 and -44. Magnavox is responsible for the ALR-50 RWR fitted to a wide range of Navy aircraft.
Aside from its Tacit Rainbow anti-radar drone and series of IRCM equipment, Northrop's products include the ALQ-135 CW jammer for the F-15C, the ALQ-162 CW jammer for various Navy aircraft and the ALQ-171 conformal countermeasures system (CCS) for the F-5E. Perkin-Elmer products include the AVR-2 laser warning receiver.
Raytheon jamming systems include the ALQ-99 pod, up to five of which are used on the EA-6B. An onboard version is produced for the EF-111A. Raytheon's ALQ-142 is the ESM system for the SH-60, its information being data-linked to the SLQ-32 EW system of the parent ship. The company's ALQ-184 pod is effectively an upgrade of the Westinghouse ALQ-119 used on most USAF tactical aircraft. The ALQ-186(V) is a US Army jammer designed for testing air defence radar systems. Raytheon is also prime contractor for the Advanced Airborne Expendable Decoy (AAED) mentioned earlier in this report.
Sanders Associates (a subsidiary of Lockheed) has over 30 years of experience in the ECM field. Its equipment includes the ALQ-126B reprogrammable jammer for US Navy aircraft, the ALQ-144, -146, and -147 IRCM series, the ALQ-149 communications jammer for the EA-6B and the ALQ-156 pulse-Doppler attack warning system. Sanders also makes the POET (Primed Oscillator Expendable Transponder) decoy, and is teamed with GE on the INEWS programme for the F-22/23.
Texas Instruments is probably the world leader in anti-radar missiles, with the AGM-88 HARM, and is prime contractor for the US Navy Generic Electronic Expendable (GEN-X) decoy. Tracor is the best-known name in dispensers, its range including the ALE-40 fitted to most USAF tactical aircraft, and the threat-adaptive ALE-45 for the F-15. Tracor is also experimenting with a towed decoy designated Big Boy.
Westinghouse has probably built more tactical jammers than any other company. It developed the ALQ-119, the first major USAF jammer pod, and is making the ALQ-131 (of which over 2000 have been ordered) for the F-16, F-111 and A-10. Westinghouse was responsible for the ALQ-153 tail warning system for the B-52, is teamed with ITT on the ALQ-165 ASPJ, and is teamed with TRW on the INEWS programme for the F-22/23. Whittaker Electronics is less well-known, but its ALQ-16(V) jammer is used on Royal Navy Lynxes and Sea Kings under the designation Yellow Veil.
In conclusion, it must be emphasised that the vast numbers of electronic warfare equipments now in service make it impractical to mention every type, and hence that the examples quoted are intended to be purely illustrative.
PHOTO : Matra's SYCOMOR optronic and radar countermeasures pod is in service with a number of
PHOTO : foreign Mirage F1-equipped forces.
PHOTO : This artist's impression displays the variety of configurations that can be given to
PHOTO : Philips's BOP 300 dispenser to suit almost any aircraft configuration.
PHOTO : Thomson-CSF has developed the Barem jammer pod. It is seen here under the wing of a French
PHOTO : Navy carrier-based Dassault-Breguet Aviation Super Etendard.
PHOTO : This German Navy Tornado carries an AEG-Telefunken Cerebus IV jammer on its outer pylon
PHOTO : and Texas Instruments AGM-88 HARM anti-radiation missiles inboard.
PHOTO : The Israeli Rafael Rattle jammer is a versatile system developed for use in aircraft,
PHOTO : ships or ground vehicles.
PHOTO : One of several possible configurations for MBB's Common Opto-electronic Laser Detection
PHOTO : System (COLDS).
PHOTO : Selenia of Italy is a highly experienced company in the field of electronics and
PHOTO : countermeasures systems, and has developed this RQH-5 ESM/ELINT suite.
PHOTO : The Erijammer 300 pod was developed by Ericsson of Sweden specifically as a self-defence
PHOTO : system for the Swedish Air Force JAS39 Gripen fighter aircraft.
PHOTO : Elettronica SpA of Italy has developed a full range of "self-sufficient" (shrouded turbine
PHOTO : provides power) Supersonic ECM pods using a basically common airframe.
PHOTO : Ferranti's AWARE-3 gives an unambiguous indication that the aircraft is being scanned by
PHOTO : enemy radar and provides its aircrew with threat type and bearing.
PHOTO : The Marconi Zeus for the RAF Harrier GR5/7 was developed with Northrop and integrates the
PHOTO : RWR with a smart jammer.
PHOTO : The Sanders ALQ-144 IRCM transmitter is used on the US Marine Corps Bell 205/UH-IH
PHOTO : Iroquois helicopters.
PHOTO : The core of the Raytheon ALQ-99 jammer pod (used on the US Navy Grumman EA-6B Prowler)
PHOTO : with aerodynamic fairings removed, showing the horn antenna.
PHOTO : The Northrop AGM-136A Tacit Rainbow is a loitering anti-radiation missile system developed
PHOTO : under a joint US Air Force/Navy programme for their B-52Gs and A-6Es.
PHOTO : The General Instrument ALR-80(V) radar warning receiver is an advanced derivative of the
PHOTO : widely used ALR-66(V) recently ordered by the RAF for its transports.