überarbeitet am 30.12.2012
In the early days of aviation, pilots used visual landmarks, buildings,
railway lines, etc. for orientation and navigation.
There are different ways for instrument flight: they pilot of an airplane can determine his own position and bearing using on-board instruments in his own plane or he can ask for an aircraft position report from a ground station. Nowadays, he will receive his position taken from radar results.
In the years of WW II, there has been a system in use by the Swiss Air Force
using a longwave transmitter on board and bearings taken by two or three ground
stations. The position was sent back to the aircraft by wireless telephony.
The Swiss Air Force two-seater airplanes Morane C 3606 have been equipped
The on-board radio compass transmitter SL 3/50 was used to give a carrier signal from an aircraft that allows bearings to be taken from ground stations to give it a position report. It was installed in front of the observer seat in the two-seater airplane C 3603.
The transmitter covers 315 - 375 kHz longwaves, there is a LV1 valve in the oscillator stage, in the HF output stage two parallel LS 50 valves, another LV1 valve is used in an AF monitor amplifier stage.
The necessary voltages are taken from the dynamotor power supply of the aircraft's FG X transmitter.
The trail antenna with a length of 72 m could be lowered to it's working position from the seat of the oberserver who did operate the equipment.
I would be very thankful for further information and images.
© 30.12.2012 Martin Bösch