Testfilm series 4

33 - 37

Status: 8 November 2012


Nachtfee Testfilm 33    (0075) Viewing the control CRT of the Nachtfee ground console. Shown both the Nachtfee time-base-reference and the transponder  Nachtfee data pulses returning like the EGON pulses towards the ground system. The real EGON pulses are manifesting themselves by quickly rotating pulse-burst (clockwise). Hence, the returning Nachtfee data pulses are still in coherence to the deflection system.

Nachtfee Testfilm 34    (0076) Viewing the simulated Nachtfee ground system, consisting of the Nachtfee ground console, the Gemse receiver and below the Nachtfee console the data converting electronics. The HF generator is the R&S SMS digital generator. On top of it the Philips LF synthesiser which generates the EGON PRF of 500 Hz (still being a sinus wave). Right of it the two pulse generator. The upper one converts the Nachtfee data signal into sharp pulses and provides also the dc driving signal for the HF modulator at 124 MHz. The lower pulse generator (Tektronix) provide the signal for the latter modulator belonging to the simulated EGON signal.

Nachtfee Testfilm 35    (0076) Viewing the simulated aircraft system (FuG136). On the left-hand-side the reconstruction of a FuG25a testing rack. On the right-hand-side on top the Philips PM5193 LF synthesiser. Below it the simulated aircraft display. The circular deflection is created by means of a X-Y Lissajous figure, using a 90 phase shifter. Below it the 26.5 V power supply for the FuG25a transponder. On the far right the moveable measurement table, providing test equipment as well as tools and that like.

Nachtfee Testfilm 36    (0080) Viewing the Nachtfee control CRT screen (LB2). The retransmission of the time-base-phase-reference pulse is being interrupted. The only signals returning is from Nachtfee data. Why we see two pulses I don't know yet. 

Nachtfee Testfilm 37    (0082) Viewing the simulated aircraft display. Please notice also the anti-clockwise rotating pulses, which constitute the simulated EGON signals. Send towards an aircraft were two signals: EGON distance measuring pulses and the Nachtfee data pulses. Both were passing through the FuG25a IFF transponder and being received at the ground control station. The crux was, that distance between ground-to-air equals air-to-ground. The returning Nachtfee data signal is necessary to exactly align the Nachtfee 'Range off-set' control. Accurate adjustment is accomplished by means of the dual beam CRT HRP2/100/1,5(A).


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