Samos (device)

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The Fu MB 4 Samos

Samos was the code name of a German radio measuring device used in World War II , more precisely a radio measuring observation device (FuMB) for ultra-short waves (VHF). The official military name of the device was "Fu MB 4" (often written: "FuMB 4"), while the manufacturer Rohde & Schwarz (R&S) gave it the type designation "RS 1/5 UD / 42 a", from which it derives Development year 1942 can be derived.

description

FuMB 4 (Samos) is used for reception of electromagnetic waves in a part of the FM frequency range (traditional 30  MHz to 300 MHz) and that of 90 MHz to 470 MHz in four switchable areas :

  • Range 1: 90 MHz… 140 MHz
  • Range 2: 140 MHz… 210 MHz
  • Range 3: 210 MHz… 310 MHz
  • Range 4: 310 MHz… 470 MHz

The measuring receiver works according to the heterodyne principle . The military designation FuMB 4 shows that there were other radio measurement monitoring devices. These include FuMB 1 (Metox) , FuMB 5 (Fanö) , FuMB 7 (Naxos) , FuMB 8 (Cyprus), FuMB 9 (Wanze), FuMB 10 (Borkum), FuMB 11 (Corfu), FuMB 26 (Tunis), FuMB 35 (Athos) and FuMB 37 (Leros).

use

“Bali” antenna on a submarine

Samos was used on airplanes, ships and especially on submarines to track down enemy radio measurement signals ( radar ) and, together with a suitable antenna such as the " Bali antenna(picture), served the purpose of a radar warning device . In conjunction with a DF antenna such as the simple dipole antenna known as the “ Biscay Cross ”, the direction of the broadcasts could also be determined. Samos has a "Search" / "Bearing" switch for this purpose. The active in the search reception automatic gain control ( "regulated") is used to Peilempfang deactivated ( "unregulated") thereby allowing the used for direction finding minimum search .

Another application was the calibration of our own active radio measuring devices (FuMG), such as the FuMG 80 (Freya) . The FuMB 5 (Fanö) developed a year later by the same manufacturer can be seen as a higher-frequency supplement to Samos, whose frequency range covers 400 MHz to 1600 MHz.

Technical specifications

Back then as “ Secret! "Declared work script with the coded manufacturing code ncv (for R&S) you can find the following information:

FuMB 4 (Samos) Specifications
Frequency range 90 MHz ... 470 MHz
Frequency accuracy 0.5  %
Input impedance 150  Ω ( symmetrical )
Intermediate frequency (IF) 2.5 MHz
IF bandwidth 50 kHz
sensitivity 12 µV input voltage for 1 V output voltage at 4 kΩ
Demodulations AM and FM
display HF - or NF - voltage
Mains input voltage 220 V
Grid frequency 50 Hz
Power consumption 34 watts
Dimensions 515 mm × 245 mm × 300 mm
Weight 20 kg

literature

  • Arthur O. Bauer: Radio direction finding as an Allied weapon against German submarines 1939-1945. How weaknesses and failures in the radio control of the submarines contributed to the outcome of the “Battle of the Atlantic”. Arthur O. Bauer Selbstverlag, Diemen , The Netherlands 1997, p. 196, ISBN 3-00-002142-6 .
  • Brian Johnson: Top Secret - Science and Technology in World War II. Motorbuch-Verlag, Stuttgart 1983, ISBN 978-3-87943-816-7 .
  • Jochen Brennecke: The turning point in the submarine war - causes and consequences 1939–1943. Köhlers Verlags-Ges. 1984. ISBN 978-3-7822-0281-7 .
  • Fritz Trenkle: The German radio measurement process until 1945. Motorbuch-Verlag, Stuttgart 1979. ISBN 3-87943-668-1 .

Web links

Individual evidence

  1. Werkschrift , accessed on June 18, 2019.
  2. Werkschrift , "Fundamental Properties", p. 3, accessed on June 18, 2019.