For who is interested in radios.
Transmitter of the period 1966, 27 Mc four channel,.picture 1, scratch built AM double simultaneous, so two tone generators. Circuit design was of Helmut Bruss, Germany!.

The receiver is "new", finished these days, superregen and equiped with 4 tonefilters (Circuit design Schumacher, Germany) to control 2 servos. Total weigh 150 gram! The old receivers did evaporate in time. The relais are "modified", from an old microwave oven.
Photograph 3 inside the transmitter. The case is designed to "store" 3 4.5 V batteries for 13.5 VDC. Currents draw 40 a 50 mA. Max current for the PA transistor, 30 mA!. All the brown sheet is "Pertinax" also the printed circuit boards..

Picture 4., amplitude modulation shown when one of the tones is activated. 1000 - 5000 Hz is used for tone filters.

In the future the plane will be rebuilt. Photograph 5 is with the 2 channel and photograph 6 with the 3 channel.
Now 4 channels! What a luxury! Hanna is proud too!! She always shows up with the result of a project, the QA employee.


TF