RD2Md

Split-anode magnetron arrangement, the local oscillator  (LO) of the Berlin radar set (FuG224), housed inside the PPI display unit (SG224) See Exhibit 2004001B

Its circuit description can be found in my 'Airborne radar' paper of 2006, held for the DEHS at Shrivenham UK (please notice page 24, figure 20)

Local oscillator of Berlin FuG224 radar apparatus (1944/45), The split-anode magnetron being pulled out of its socket a bit. Just visible is that this tubes was accepted by the German Armed Forces in week 1 of 1945 (= 0145). C = resonant tuned cavity; M is the permanent magnet, which field stands across the split-anode inner space, parallel with the filament; S is a matching stub.

The actual front-end mixer fed by this LO signal, was, however, housed in the Berlin transmitter unit (like in British H2S), very near to the antenna-connector (we do not have this Berlin transmitter, only known from photos). This  connector type was called by the Germans 'Rotterdam Stecker' (Rotterdam connector), originating from the place where they had discovered on 3 February 1943 a H2S apparatus, which they code-named Rotterdam-Gerät. The German coaxial connector looks very similar to the British one, however, they differ slightly because the Germans used metric measures. I have deduced this, because we have such a cable with connector, that just does not fit onto a genuine British H2S transmitter (very minor differences).

RD2Md being pulled out. Its lecher-line-output* is picked-up by capacitive means and frequency tuned by means of the resonant cavity C (nevertheless, H2S used a reflex klystron instead)(controlled manually at the front panel of the Berlin PPI unit, as was also done similarly in early British H2S sets) * The black-strips on the  left,  inside the glass envelope

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