Neptun (radar)

Neptun (Neptune) was the code name of a series of low-to-mid-VHF band airborne intercept radar devices developed by Germany in World War II and used as active targeting devices in several types of aircraft. They were usually combined with a "backwards warning device", indicated by the addition of the letters "V/R" Vorwärts/Rückwärts, meaning Forward/Backward). Working in the metre range, Neptun was meant as a stop-gap until scheduled SHF-band devices became available (for instance the FuG 240/E cavity magnetron-based FuG 240 Berlin AI radar).^[1]

Transceiving antennas used for Neptun on twin-engined night fighters usually used a Hirschgeweih (stag's antlers) eight-dipole array with shorter elements than the previous 90 MHz SN-2 radar had used or as an experimental fitment, the 90°-crossed twin-element set Yagi based Morgenstern single-mast-mounted array.

Variants

FuG 216: Experimental series to plan the further development. Installed in Fw 190 A-6/R11 and Bf 109 G-6^[2] The aircraft were used by NJGr 10 until March 1944, after which some machines of 6./JG 300 (Kommando Plöger) were equipped.^[3]

Manufacturer: Flugfunkforschungsinstitut Oberpfaffenhofen (FFO, German for airborne radio research institut in Bavaria)
R1 version (backwards warning device)

Frequency: 182MHz
Power: 1.0kW
Transmitting and receiving antennas each consist of twin dipoles, mounted under and above the wings, respectively
Single display device with distance readout

V version (for single engined night fighters)

Frequency: 125MHz
Power: 1.2kW
Range: 500 to 3,500m
Antennas in the form of spikes or (Fw 190) as "antlers" on right and left wings

FuG 217: Installed mainly in Ju 88 G-6, only a few Bf 110 G-4, He 219 or Me 262 received the Neptun. It could be combined with the additional Elfe device to automatically measure the target distance and fire the guns at a set range.^[4]

Manufacturer: FFO
R2 version (backward warning device)
J2 version (for single-engined night fighters)
Ausführung V/R (combined night fighter and backward warning device for two-engined fighters)

Two switchable frequencies: 158 and 187MHz
Search angle: 120°
Range: 440–4,370 yd (400–4,000 m)
Spike or "antler" antennas

FuG 218: mass-produced

Manufacturer: Siemens / FFO
R3 version (backward warning device)
J3 version (for single-engined night-fighters)
V/R version (combined night fighter and backward warning device for two-engined fighters)

Six switchable frequencies: 158 to 187MHz
Search angle: 120°
Range: 130–5,470 yd (120–5,000 m)
Weight: 110 lb (50 kg)
R3 and J3 with spike antennas and V/R with "antler" antennas.

G/R version (combined night fighter and backward warning device for two-engined fighters)

Only one single device built, replacing the 2kW transmitter with a 30kW transmitter. Range increased to up to 6.2 mi (10 km). This device was intended for the Dornier Do 335. "Antler" antennas.

References

^ Aders, p. 269
^ "Focke Wulf 190 A6 R11 Nachtjäger". Archived from the original on 2009-12-27. Retrieved 2011-12-26.
^ Aders, S. 210
^ Aders, S. 268

(1) TME 11-219 Directory of German Radar Equipment
Gebhard Aders: Geschichte der Deutschen Nachtjagd, Motorbuch publishing corporation, 1977, ISBN 3-87943-509-X
File:Neptun FuG 217.pdf

[1] Aders, p. 269

[2] "Focke Wulf 190 A6 R11 Nachtjäger". Archived from the original on 2009-12-27. Retrieved 2011-12-26.

[3] Aders, S. 210

[4] Aders, S. 268

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v t e German radars of World War II
Aerial	Hohentwiel ASV Lichtenstein Neptun Berlin A Berlin N
Land-based	Freya Jagdschloss Mammut Wassermann Würzburg
Naval	Seetakt FuMO 21 FuMO 24 Hohentwiel FuMO 81, 83 and 84
List of World War II electronic warfare equipment

Variants

See also

References