To understand the principles of Rehbock, please read first:
a German test equipment, which could accurately calibrate the radar's range reading
by Arthur O. Bauer
The Germans used a very cleverly designed apparatus, which employed piezo-electric and acoustic phenomena in either directions. It is based on the fact that "time and range" are proportional.
Its nomenclature was: FuZG xx (Funkzielgerät xx)
Würzburg, Mainz and Manheim radar systems all used type FuZG 64, whereas, for instance, FuG 220 = Liechtenstein SN 2 used type FuZG 220 (may be FuZG U5?). Only 1500 sets had been built (according Hoffmann-Heyden's book on "FAS III").
To enhance understanding, consider my book on Würzburg: Deckname Würzburg (Wuerzburg, Wurzburg), and: Exhibits and: (Notice also: Würzburg set-up) and: auxiliary test instruments, click on this line! Consider also its integral Rehbock FZG64 manual
Look also at our patent selection: Patent DE (enter keyword-word: Rehbock and about 12 references will be presented) For those not acquainted with this kind of searching, please click first on: PDF documents, how to approach it for keywords effectively, and follow the instructions.
Shown is, a screen photo from our Würzburg radar display unit ANG 62, which was taken in 1983/84. Employing the Würzburg apparatus (FuSE62 D - FuG 62 D) electrically. The radar pulse (TP) was absorbed in a dummy load. Parallel onto it was linked the Rehbock FuZG 64 range calibrator. For this occasion, the Urechse SÜ 62d transmitter and receiver module was set at ≈ 525 MHz (Wismar Insel B).
AT = artificial target signals received from the Rehbock range-calibrator (transponder)
TP = transmitter pulse at range = 0 hm (hekto meter(= hecto metre), a distance measure generally, used by German artillery and Flak)
This photo shows as to how Rehbock was mounted on top of a mast, and Würzburg had to be set-up (prepared) for precise range calibration. Both antenna directions had to match (point) exactly in line.
Close-up photo of the Rehbock FuZG64 on top of a mast (hight 14 m)
The stick on top of the Rehbock antenna reflector, holds a small mirror. The Würzburg parabolic dish has a peep-hole, which is exactly (equally) out of (the) antenna centre (focus). As to obtain accurate alignment of both antenna axis.
The crossed dipoles are circular polarised, as to follow the direction of rotation of the Würzburg pencil-beam. The multi-pin-plug at the bottom of Rehbock is to connect the remote control box BG64 (see next photo)
The remote controle box BG 64 (Bediengerät 64)
The "flywheel knob" on the right of the front panel, is linked to an arrangement of switching contacts. By means of manual rotation the servo voltage is generated*. This signal is steering (controlling) the LO tuning (slave) servo inside the Rehbock transponder. (regard also: Würzburg set-up and also: Na-Liste final paragraph *(thus, on this side was no master servo engaged, though, the three phase AC signal was manually generated by means of alternating contacts. The reason for doing it this way, may have been that precise servos need to be powered by an AC signal of several hundred Hertz, which wasn't available)
Funkzielgerät 64 (FuZG 64)
Ln.7099 (=Luftwaffe stock number), Werknummer (serial) number 433615. It may well be, regarding German wartime practice, that it actually has serial number "615". It was manufactured by: bou = Telefunken
A-B/X might indicate, that its frequency spectrum covers Wismar Insel A and B. We have, however, operated our Rehbock on 510 MHz and tuning gave no problems. On the right is the antenna connector, which is illustrated previously ("Senderteil SZG64").
This is an very informative plate. It says: that Rehbock should be placed (exactly) 30 metres from a Würzburg* antenna (equally for the small and Giant Würzburg FuSE65). The coarse range markers at the ANG62 screen are also calibrated in "hecto metres" (hm = 100 metres interval). Hence, 47,35 means 4735 metres. Letzte Eichung explaines, that this set was calibrated on 14 February 1945 for the last time. Its first calibration was on: 31 May 1944. These intervals indicate that calibration had to be repeated frequently. We know already, that about 1500 Rehbock devices existed, and that calibration parties travelled around in Europe. Sites were regularly visited, regarding the circumstances, every three months. Please notice, that the range blips are not exactly multiplied by a factor 2! It is also clear, that the speed of the acoustic waves propagating inside the glass-delay-line, which was fit with the surface of a quartz resonator at 26.1 MHz, tended to retard in time. Thus, the time of travel of both the EM radar signal and the acoustic waves propagation tended to increase steadily a bit. *FM = Funkmessgerät = radar installation
The text is self-explaining. LD 5 is the LO* valve, tuned by means of the servo signal from BG 64. LD2 is the mixer valve. The quartz/glass-delay-line is explained in: Rehbock a German test equipment, which could accurately calibrate the radar's range reading . Würzburg, like several other German radars, used for sensible systems 180 volt stabilized AC sources. FuZG64 and BG64 were also fed in this way (carbon-pile regulator made [designed] by Julius Pintsch, also known as "Pintsch Regler"). *(local oscillator)
Rehbock inside view, power supply module being removed. All die-castings are made of so-called "Spritzguß" (Mg-Al alloy).
Please consider also our new Wurzburg "radar repair report", which is showing the way it takes bringing our Würzburg to life again (late 2009/early 2010)
All our systems are now on display in the new museum premises, since 2009
Consider also, or go back to: auxiliary-gear
Consider also, or go back to: Archive displays
Consider also: Na-Liste of the Kriegsmarine last field
Back to: subject details
Consider also: References