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.
At least in the Swiss variant, two mechanically pre-tuned frequencies could be selected by the help of Bowden cables.

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.
The aircraft station FG IV has been withdrawn together with the airplanes where they had been instelled in the years 1945 - 1954.

I would be very thankful for further information and images.