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German Radar of WWII

From Japanese Electronics, OPNAV-16-VP101, Photographic Intelligence Report 1, Air Intelligence Group, Division of Naval Intelligence, Office of the Chief of Naval Operations, Navy Department, January 1945:

German Radar Summary

Examples of German Radar are included here to cover the possibility that the Japanese may have access to German equipment and technicians.

The Germans employ several types of land based installations covering the functions of Air Search, Fire Control, and Coast Watching.

These types are quite well standardized and are much more efficient than those the Japanese are known to have.

There is now some photographic evidence of German Radar equipment in use by the Japanese. Also, it is knowrn that many other types of German electronics equipment are being used.

The following table represents the latest list of German Radar types with salient information concerning each.

GERMAN LAND BASED RADAR
NameSize of Screen*Top of Screen Above GroundFrequencyRange in Nautical MilesUse
LIMBER FREYA20’x 16′
IFF – 16¼ x 3½’
26¾’
30′ with IFF
116-146 MCS.75A.S.
POLE FREYA 20’x 16′
IFF – 16¼ x 3½’ or 20′ x 8′
32′, 35′ or 40′ with IFF116-146 MCS.100A.S.
GIRDER CHIMNEY19½’ x 97½115′120-130 MCS.110A.S.
CYLINDRICAL CHIMNEY60′ x 97½
IFF .22′ High
110½’120-130 MCS.160A.S.
GEMA COASTWATCHER20′ x 8′25′370-390 MCS.Depends on elevation (ASL) of siteC.W.
LARGE COASTWATCHER35′ x 34′40′70-90 MCS.60-75C.W.
SMALL HOARDING63¾’ x 44¾’50′  C.W.
LARGE HOARDING98′ x 36½’50′120-130 MCS.100-115C.W.
SMALL WURZBURG10′ Diameter12½’ in Vertical Position550-580 MCS.25F.C.
GIANT WURZBURG24′ Diameter27′ in Vertical Position470-580 MCS.40G.C.I., A.S. & C.W.
* – Width (Horizontal Dimension) Given First
A.S. – Air Search
F.C. – A/A Fire Control
C.W. – Coast Watching
G.C.I. – Ground Control Intercept

Drawings of all of the basic German Radar types are included on this page. Best known popular names are used for the designation of each type. It will be noted that these designs are quite well standardized for each particular use, and identification is easier because of this fact.

In most cases, this German equipment is superior to that now in use by the Japanese. A constant watch for German type designs of Radar in Japanese held territory is therefore in order.

German Radar of WW2

 

Small Wurzberg German Radar

Report on the German “Small Wurzburg” radar from U.S. Naval Intelligence report Japanese Electronics, March 1945:

The “Small Wurzburg” or “Bowlfire” was first designed in 1936, and is one of the most efficient Radars. It is primarily for A.A. fire control but has been used for A/C reporting, searchlight control, and as a standby for Ground Control of A/C. In general, it is a mobile Radar, mounted on a four-wheeled trailer with outriggers for levelling. Some sets are emplaced, however, and the wheels removed.

Search is by mechanical rotation of the apparatus for bearing and by elevation of the reflector bowl for height measurement.

The diameter of the paraboloid reflector is 10 feet, the top of which is but 12½ feet above the ground. A cupboard, housing the radar equipment, and an operators seat are attached to the rear and side of the reflector.

Small Wurzburg German Radar

There are several types of Small Wurzburgs; among them Types “A”, “C”, and “D” are most used and are quite similar. Type “D” is found with limber mounting and may be without wheels or even set in concrete.

For transport, the paraboloid can be split, by hinges, and turned down in two halves.

Type F.M.G. 41-T is a modification of the Small Wurzburg which incorporates a scoop-like form for cutting out ground echoes.

The practical range of the Small Wurzburg is not more than 25 nautical miles but it has a high degree of accuracy for Fire Control purposes.

Airborne Jammer Radar Set AN/APT-1

A description of Airborne Transmitting Equipment AN/APT-1 used to jam enemy radars in WWII from Graphic Survey of Radio and Radar Equipment Used by the Army Air Forces, Army Air Forces, Air Technical Service Command, Wright Field, Dayton, Ohio, February 1945:

Transmitting Equipment AN/APT-1 is an airborne transmitter used to jam enemy radars in the 95-210 mc. frequency range. This band includes most of the enemy early warning radars such as the German Freya, Hoardings and Wasserman and Japanese radars of equivalent type. The equipment employs the DINA (Direct Noise Amplification) type of transmission and may be used either as a spot jammer or as a barrage type jammer.

The carrier frequency is suppressed and all of the output power is concentrated in the side bands, affording more effective jamming coverage with less power. It will effectively screen an AN/APT-l equipped bomber to within two miles of a Freya radar.

B-17 Bomber Radar Jammer

Radar Transmitting Equipment AN/APT-1 (Installed in B-17) may be used for spot or barrage jamming of enemy radars in the frequency range from 95 to 210 mc. (i.e. German Freya or Japanese equivalent types.)

For barrage jamming the equipment is adjusted to the required frequency prior to take-off, after which only the power output need be controlled.

For spot jamming the set must be tuned in flight by means of the control unit. Employing R-F Amplifier AM-14/APT or AM-18/APT the output of the equipment can be increased effectively. Two sets of three antennas are available for complete frequency coverage. All are of the quarter-wave stub type. One set is designed for vertical mounting and the other set is designed for mounting at an angle of 45 degrees.

Power is obtained from an 80/115 volt, 400-2600 c.p.s., a.c. source and a 28 volt d.c. source.

Test equipment required for the maintenance and tuning of the equipment includes Test Set I-139-A, Amplifier Alignment Unit TS-92/AP, Radio Frequency Wattmeter TS-118/AP or TS-92/AP, Pickup Assembly TS-131/AP, Test Set I-56-K and Frequency Meter TS-174/AP.

Army Supply Program requirements as of 20 November 1944 were 4,895 for the calendar year 1944 and 3,086 for 1945.

POWER INPUT   325 WATTS
POWER OUTPUT   30-8 WATTS (All sideband)
FREQUENCY   95-210 MC.
TYPE OF SIGNAL   DIRECT NOISE

TUBE COMPLEMENT
NO.TYPENO.TYPE
25R4GY16X5GT
36AC71931A
26C42832*
16V6GT/X1829B*
*One 829B substituted for one 832 for increased power over 95-150 Mc.

Radar Jammer Antenna Stub

(i) Antenna Stubs AT-36/APT, AT-37/APT and AT-38/APT are similar except they are for vertical mounting. (ii) Control Unit C-58/APT-1. (iii) Radar Transmitter T-28/APT-1.

RADAR SET AN/APT-1TOTAL WEIGHT 70 LBS.
ComponentNomenclatureSizeWeight
Radar Transmitter T-28/APT-17 5/8″ x 10 1/8″ x 21 3/4″43 Lb.
Control Unit C-58/APT-13 1/2″ x 3 1/2″ x 2 1/2″1 1/2 Lb.
Mounting Base MT-171/U 2 1/4″ x 10 5/8″ x 22″3 1/4 Lb.
Mounting Base MT-114/APT-15″ x 5″ x 3/4″1 1/4 Lb.
Antenna Stub AT-36/APT or AT-41/APTLength 16 1/2″6 1/2 Lb.
Antenna Stub AT-37/APT or AT-42/APTLength 22 1/2″6 1/2 Lb.
Antenna StubAT-38/APT or AT-43/APTLength 29″6 1/2 Lb.
and includes plugs, adapters, and misc. cables.