SE-103 / RTS
überarbeitet am 30.8.2010
Telefunken, Zurich, tried another way to design a successor to the single frequency
SE-100: their SE-103 uses plug in frequency modules to select the different frequencies
in contrast to the switchable crystals in the rotating "crystal drum" of the SE-101 / SE-102
developed by Autophon.
The wireless set SE-103 is a portable transceiver, it comes with a metal cabinet
with the dimensions of 323 x 148 x 95 mm, a weight of 5,1 kg and is usually
carried in front of the soldier's chest. A small canvas bag is used to store
headphones and throat mikrophone combination. The transmit - receive switch
can be attached to the uniform by use of a metal clamp, so it can be operated
will a pressure of the elbow - the SE103 has been ins use with the cavalry, so the
soldiers had their hands free to hold the horse's rein.
With it's output power of 0,2 Watts, the standard communication range is 3 km at daytime and around 2 km during the night, it is smaller then the range of a common CB set.The receiver is a single conversion circuit, the R.F. signal from the antenna has to pass one R.F. amplifier stage (1T4) and is mixed with the signal of the crystal oscillator (1R5); the intermediate frequency of 455 kHz is amplified in two stages (1T4, 1T4); after demodulation and the aufio frequency preamp (1S5) and final amplifier (3S4) it is fed to the headphones. The set has no squelch function, so an annoying hiss is present all the time, when the set is switched on.
In transmitting mode, the audio signal coming from the microphone has to pass a three stage amplifier (1T4 / V5) used for transmitting only; 1S5 and 3S4 / V6/V7 used in receive and transmit mode), mixed with the oscillator signal (1R5) and is amplified in the R.F. final tube (3S4) to reach an output power of 0,2 Watts.
The heaters of the valves V5, V8 and V9 are active only when the transmit switch is pressed, this arrangement does save battery power but You have to wait 2 seconds before You start talking after You press the transmit switch.
To operate the set, insert the heater and anode / B+ battery in the battery compartment
at the bottom of the transceiver.
© 30.10.2008 Martin Bösch