EW - asv

Air-to-Surface Vessel, ASV

The purpose of ASV is to detect ships from aircraft at greater ranges than is possible by eye and under conditions of poor visibility. Such equipments are installed in aircraft of Coastal Command and the Fleet Air Arm to assist in the location of submarines, ships, and convoys. The earliest models employed a frequency of 176 Mc/s (1,7 metres) but their performances were inadequate. Later versions work on the S or X bands (9,1 or 3 cm) and are fare more effective than the 1,7 metre ASV.

ASV Mk I
ASV Mk IA
ASV Mk II
ASV Mk III
ASV Mk IV
ASV Mk V
ASV Mk VI
ASV Mk VIA
ASV Mk VIB
ASV Mk VIC
ASV Mk VII
ASV Mk VIIA
ASV Mk VIII
ASV Mk IX
ASV Mk X
ASV Mk 11
ASV Mk 12

ASV Mk I

Year of issue

RAF designation
Frequency	16-49 meter
Range	extremely short
Main items	Receiver Transmitter Indicator Power unit	R 3009 (or 3009A) T 3010 (or 3010A) Type 3 type 21
Remarks	Hudson

ASV Mk IA

Year of issue

RAF designation
Frequency	16-49 meter
Range	extremely short
Main items	Receiver Transmitter Indicator	R 3038 (or 3038A) T 3010 (or 3010A) Type 3
Remarks	Sunderland

ASV Mk II

Year of issue	early 1940

RAF designation	ARI 5001 / 5002 / 5007 / 5008
Frequency	176 Mc/s
Pulsewidth	1,5μs at a recurrence frequency of 1200 Hz
Range	on ship up to 12 miles on coastline 50-70 miles on beacons 80-90 miles on BABS beacons 12 miles at 1000 feet.
Main items	Receiver Transmitter Indicator	R 3039 (or 3039A) T 3040 (or 3040A) Type 6 (or 6A)
Test gear	Calibration Polarization	TS 76 TS 81 TS 21 TS 28 TS 19 TS 75 W 1158
Remarks	Developed at Royal Aircraft Establishment at Farnborough SCR 521 (170-196 Mhz) is based on the ASV Mk II (BC 700, 701, 702, 703, 704, 961 (AN/TRS-1)

ASV Mk III


Year of issue

RAF designation	ARI 5119
Frequency	S-Band
Range
Main items
Remarks	Similar to H2S Mk I

ASV Mk IIIA

	Airborne S-band equipment for detection of surface vessels (ASVS)
Year of issue

RAF designation	ARI 5153
Frequency	10 cm
Range	6 miles
Main items	Switch unit Indicator Switching unit Scanner Lucero	type 207B type 184 (or 184A) type 247 type 116 TR 3190 or TR 3160
Remarks	Similar to H2S Mk IIA

ASV Mk IV

Year of issue

RAF designation
Frequency
Main items
Remarks	Only a few produced by Radiation Laboratory.

ASV Mk V

	American S-band airborne equipment for detection of surface vessels Fitted in British Coastal aircraft.
Year of issue

RAF designation	ARI 5704
US designation	ASG-1
Frequency	10cm
Main items
Remarks

ASV Mk V A


Year of issue

RAF designation	ARI 5704 ?
US designation	AN/APS-2 ASG-3
Frequency	10cm
Main items	improved version of ASV Mk V with increased power.
Remarks

ASV Mk VI


Year of issue

RAF designation	ARI 5568

Frequency	10cm
Main items	Transmitter/Receiver Receiver Indicator Switch unit Modulator Power unit Power unit Control unit Control unit Control unit Junction Box Waveform generator Scanner unit Lucero	TR 3519 R 3553 (or 3554) Type 162B (or 163B) type 207B type 158 type 224 type 280 type 218 type 444 type 448 type 231 Type 34 (or 35) type 67 TR 3566
Remarks	200kW, S-Band

ASV Mk VIA

	Essential difference with ASV Mk VI is the ability to change the scanner from a simple rotation which gives an ordinary PPI picture.
Year of issue

RAF designation	ARI 5571

Frequency
Main items	Transmitter/Receiver Receiver Indicator Switch unit Modulator Power unit Control unit Control unit Control unit Waveform generator Scanner unit	TR 3519 (or 3519A) R 3553 Type 162B type 207B type 158 type 280 type 454 type 444 type 448 Type 34 (or 35) type 68
Remarks	Wellington Leigh Light aircraft. Incorporates automatic lock follow.

ASV Mk VIB


Year of issue

RAF designation	ARI 5604

Frequency
Main items	Transmitter/Receiver Receiver Indicator Switch unit Power unit Power unit Control unit Control unit Waveform generator Scanner unit	TR 3523A/WW (or 3159) R 3553 Type 216 type 207B type 517 type 617 type 492 (or 454) type 498 Type 34 (or 35) type 68
Remarks	Warwick & Wellingon

ASV Mk VIC

RAF designation	ARI 5634
Function	ASV Mk6C is an airborne radar equipment used for target location over the sea and as a navigational aid on flying boats of Coastal Command. The ASV Mk6C installation is fitted with synchronized twin scanner systems, Type 12 and 53, and scanner for port and one for starboard. These scanners are fed with pulses from the UHF transmitter through waveguides and a attenuator, thence to a waveguide switch type 247. This switch ensures that each scanner is transmitting and receiving only when it is sweeping out the arc further removed from the aircraft. The reflected pulses are received on the scanners and the presentation is built up on the plan position indicator. By observation on this and a subsidiary CRT known as the height tube, the navigator can navigate or home on to a target without the necessity of direct vision.
Year of issue
Wavelength	9.1 cm
Pulse width	1 microsecond
Pulse recurrence frequency	670 p.p.s.
Frequency control	Magnetron
Range scales	10, 30, 50, 50 to 100 miles
Power supplies	24Volt aircraft supply through motor generator type 4B which gives the 80Volt AC supply for the installation.
Power consumption	1600 Watts
Power output	150 to 180 kW
Main items	Transmitter/Receiver Transmitter/Receiver Receiver Indicator Switch unit Amplifying unit Modulator Power unit Power unit Scanner control unit Tuning Control unit Junction box Waveform generator Scanner unit Aerial	TR 3519 TR 3566 (for B/A facilities) R 3585 Type 216 or 162, 233 type 207B, 247 type 171 type 158 type 567 type 617 type 411 type 444 (TR3519A) or 498 (TR3519B) Type 249, 269 Type 34 (or 35) type 12 (port scanner) & type 53 (stbd scanner) Type 301
Remarks	.

ASV Mk VII

RAF designation	ARI 5569

Year of issue

Frequency	3cm
Main items
Remarks	1944

ASV Mk VIIA

	Complete working, click to enlarge!
RAF designation	ARI 5573
Function	This equipment is used for Air Sea Rescue Operations and also for general reconnaissance. Originally it was designed solely for ASR operations and thus the scanner (Type 106) had a narrow beam (6 deg. horizontal, 3 degrees azimuth) radiating from horizontal to approximately 6 deg. below; there was practically no radiation in the vertical plane. therefore the scanner was modified by the addition of a perspex prism which scattered about 10 percent. of the radiation downward, thus giving coverage over a much greater area. The maximum range was only slightly reduced due to this redistribution. The modified scanner, which is similar in all other respects is designated the Type 116. A height tube Is fitted in the equipment but it is used only for the observance of echoes far tuning and monitoring and not for giving height Indications.
Year of issue
Wavelength	3 cm
Pulse width	1 microsecond
Pulse recurrence frequency	670 p.p.s.
Frequency control	Multivibrator
Range	Minimum 3/4 mile at 500 ft, 3mile at 2000 ft. Maximum 80-100 miles
Range scales	10, 30, 50, 50 to 100 miles
Peak power output	45 kW
Power supplies	80Volt 2000c/s from generator type U2 controlled by voltage control panel type 5 28Volt DC from aircraft supply
Power consumption	900 Watts AC, 1000 Watts DC
Main items	Transmitter-Receiver Modulator Waveform generator Switch unit Receiver unit Indicator Heading control unit Junction Box Scanner speed control unit Tuning control unit Scanning unit Power unit Power unit Voltage control panel	TR 3523A (or 3523E) type 64 (or 64B or C) type 34 (or35) type 207B R 3553A type 162C type 446 type 334 type 477 (or 477A) type 499A (or 499B) type 106 modified to 116 type 567 (or 567B or C) type 617 (or 617A or B) type 5
Test gear	Waveform monitor Range calibrator Dummy load Dummy load Dummy load Milliammeter Milliammeter Signal generator Current pulse transformer Bench scanner mounting	Monitor type 28 Test set type 202 type 228 type 230 type 231 type F (0 to 2mA) type H (0 to 10mA) type 106 or type 52A Transformer type 782 mounting type 731
Remarks

ASV Mk VIII


Year of issue

RAF designation
	ASD
Frequency
Main items
Remarks	American X-Band equipment

ASV Mk VIII A


Year of issue

RAF designation	ARI 5607 (5764)
US designation	AN/APS-4 ASD-1
Frequency
Main items
Remarks	Lightweight American X-Band equipment forward locking equipment for use in the Fleet Air Arm. Build in the form of a bomb and can be jettisoned if necessary.

ASV Mk IX


Year of issue

RAF designation
US Navy designation	ASH
US AAF designation
Frequency
Main items
Remarks

ASV Mk X


Year of issue

RAF designation	ARI 5652
	AN/APS-15
Frequency
Main items
Remarks	X-band all-round locking equipment of American design.

ASV Mk XI


Year of issue
RAF designation	ARI-5553
	ASVX Mark I
Function	The ASV. Mk.XI is fitted in Naval aircraft to give information of the range and bearing of surface vessels. As a navigational aid it gives indications of position and range of coastlines ; Lucero is fitted so that 1,5 metre beacons facilities may be used. Two forms of presentation are used ; a PPI for medium and long range (5-100 sea miles) and a range-azimuth for short range (0-5 sea miles). When using the PPI presentation the range is indicated by the distance that the echo appears from the centre of the tube, whilst bearing. relative to the aircraft heading is given on the clock-face system ; 12 o'clock position represents the aircraft heading. The range-azimuth presentation covers an angle of 30 deg. to either side or the aircraft heading ; It is basically an enlargement of a 60 deg., 0-5 mile segment of the PPI presentation and appears as a vertical timebase. Range is indicated by the distance up from the base of the tube and the bearing by the position relative to the vertical centre line.
Type of wave	Pulse
Wavelength	3cm
Pulse width	1u sec
Peak power output	40kW (approx.)

Main items	Amplifier A-3583 HF Unit TR-3530 (Swordfish) or TR-3529 (Barracuda) Power unit 529 Control unit 478 Indicator type 97 Scanning unit 78 (Barracuda) or 79 (Swordfish) Modulator type 64 Junction box type 92 & 214 Interrogator Lucero TR-3507 (Swordfish) or TR-3505 (Barracuda) Voltage control panel type 3A (Swordfish or type 6B (Barracuda)
Remarks

ASV Mk XII


Year of issue
RAF designation	ARI-5614
Function	The ASV Mk.XII is fitted in Naval strike aircraft to give ASV and AI facilities on the same equipment. it is basically an AI Mk. 8, the scanner of which has been adapted to give a spiral scan in addition to tile conical scan of the AI. The change over from one type or scanning to the other is made by operation of a lever in the observer's cockpit. Beacon facilities are made possible by the addition of Lucero operating on 176/177 Mc/s. Each type of scan has its own individual type of presentation : the conical scan has the normal AI presentation, that is, the target response is in tile form or an arc ; the length of the arc gives an indication of the amount that the target is off centre and the radius of the arc is an indication of range. The spiral scan is presented on a vertical timebase, the amount of the "blip" is off-centre to the timebase is an indication of the amount the target is off course, and the distance that the "blip" appears up from the base line is indicative the range.
Frequency	9.1 cm
Power output	90 kW.
Type of wave	Pulse modulated
Pulse width	1 u sec. 2 u sec on 100-mile range
Pulse recurrence frequency	2,500 for ASV. 932 for beacon
Range	AI 2.000-9.000 ft. ASV and beacon 90 miles
Main items	Receiver unit type 184 Indicating unit type 198 Modulator type 206 Power unit 225 Transmitter-receiver type TR-3151 Strobe unit type 68A Control unit type 462 Junction Box type 67 Scanning unit type 73 Aerial system type 196
Remarks	Carries Lucero TR-3549

ASV Mk XIII


Year of issue
RAF designation	ARI-5650
Function
Frequency
Power output
Type of wave
Pulse width
Pulse recurrence frequency
Range
Main items
Remarks	Improved ASV Mk XI with greater power output. Designed for Fleet Air Arm, and for Coastal Command mosquito's