First child (radar)
The on-board radio FuG 25a Erstling was installed in Luftwaffe aircraft from 1941 onwards in the Second World War to enable its own radar stations to recognize friend and foe . The development of the company GEMA received the impulses from the German Freya or Würzburg radar stations and responded with a fixed signal. The FuG 25a later became a central component of the EGON-Jägerleitververfahren .
use
The first-time identification device was activated by the ground station by switching the pulse repetition frequency from 3750 Hz to 5000 Hz. The device responded to the radar station on 156 MHz with a programmed Morse code . A motor-driven cam controller served as the code transmitter . This was provided with two coding keys, each of which represented a ten- bit long code. Additional devices were required for use in conjunction with Würzburg devices : an interrogator with the code name Q device (cow) and the identification receiver chamois .
Countermeasures
In the summer of 1944, the first British mosquitos were equipped with the Perfectos device, which activated the FuG 25a and thus made it possible to locate it. The usability of the debut was significantly restricted because the German night fighter crews had to switch off the debut devices as a countermeasure.
Technical specifications
- Receiver: 125 MHz (Freya) and 550-580 MHz (Würzburg)
- Sensitivity: 2 mV
- Transmitter: 156 MHz
- Transmission power: 0.2 watts
- Activation: radar pulses with 5000 Hz
- Key: 2 times 10 bits
- Range: 40 km (FuG 25) and 270 km (FuG 25a)
| FuG 25 | FuG 25a | |
| Receiving frequency | 560 MHz | 125 ± 8 MHz |
| Transmission frequency | 156 MHz | 156 MHz |
| Transmission power | unknown | 400 W ( PEP ) |
| electricity | 4 A DC | 4 A DC |
| Supply voltage | 24 V DC | 24 V DC |
| Weight | 11 kg | 17 kg |
| Tube assembly | 6 × RV12P2000 , 1 × LD1 | 7 × RV12P2000, 1 × RG12D60, 2 × LD1, 1 × LS50. |
| Range | 72 km (40 miles ) | approx. 80% of the optical range of vision, max. 270 km (150 miles) |
Safeguards
The German Air Force was known to have small explosive charges attached to sensitive equipment like this one. These should enable the facility to self-destruct before it could be captured by the Allies. A small fuse allowed the crew to get to safety in good time.
See also
- Radio measuring devices - overview of German radar devices in World War II
- Wilde Sau night hunting procedure
literature
- Christian Möller: The operations of night battle groups 1, 2 and 20 on the Western Front from September 1944 to May 1945. ISBN 978-3-938208-67-0 .
- Fritz Trenkle : The German radio control procedures until 1945. Dr. Alfred Hüthig Verlag, Heidelberg 1987, ISBN 3-7785-1647-7 .
- Werner Gierlach: flight reporting service. Booklet 8, Freya-Fibel, Cologne, pp. 43–44.
- TME 11-219 Directory of German Radar Equipment (PDF)
Web links
- Description and photos of FuG 25a
- Technical description, u. a. of the key giver (PDF, English; 2.2 MB)
- Technical description of various German IFF devices (PDF, English)
- “Jagdschloss” radar; Course material of the Luftnachrichtenschule 8 Detmold (PDF)
- Jagdschloss, more pictures
Individual evidence
- ↑ Gebhard Aders : History of the German night hunting. Motorbuch Verlag, 1977, p. 303.