überarbeitet am 31.12.2012
The Aircraft Wireless Station FG IV has been ordered in 1937/38. The station
based on Telefunken aircraft station Stat 1005a F has beeen produced under Telefunken
licence by Telefunken Zurich.
Based on the construction of Telefunken Aircraft Station Stat 1005a F (with it's components Transmitter As 82, Receiver Ae 83 and antenna tuner Al 84), Telefunken adapted the station slightly for the Swiss Air Force, it was introduced as FG IV. While the German station was intended to be used in single seat fighters (and had to be operated by the pilot himself), the station was installed in Switzerland only in two-seated airplanes and was operated by an oberserver / wireless operator.
As German industrie was switched for war production, the station has been produced under Telefunken licence in Switzerland: the transmitter was produced by Telefunken Zurich (Albiswerk), the receiver by Zellweger, Uster.
The receiver Telefunken E 406 F is a five valve (all NF4) superhet covering 3000 - 6000 kHz in the shortwave band.
The transmitter Telefunken S 347 F covers also 3000 - 6000 kHz in
the shortwave range. In the modulator three (or four?) valves NF4 (later RV12P4000)
are used, one of them as AF generator, two more as modulation amplifiers. One
RS287 (RL12P35) is used in the driver stage and two more RS287 in the RF final stage.
The output power is 60W in CW telegraphy and 25W in telephony.
The system is equipped with an antenna tuner.
The valve heaters are powered from the airplane's on board accumulator, the plate voltage of 600 - 800 V is generated by a dynamotor.
Both operation frequencies were mechanically pre-set from ground personnel,
the used the high accuracy wave meter Telefunken Spez 831 F.
There is some evidence, that the components of the FG IV have also been used
as ground station with the designation Z-Station 38.
I would be very thankful for further information and images.
© 31.12.2012 Martin Bösch