Funkstation SE-208 (Autophon TR94/8); developed by Autophon AG, Solothurn.
In the years after WWII and the fifties, a modernization of the wireless equipment of the Swiss Army was absolutely urgent.
The Swiss army still relied on the „Light Portable“ station, a station designed in the early thirties which was quite reliable but had to be carried around by four persons, and some recently acquired U.S. americal surplus sets operating of higher frequencies in FM mode and thus being incompatible with the older equipment.
The wireless stations SE-206/209 (similar sets, different frequency range according to the different troops) could be used as portable manpack set as well es vehicle mounted on jeeps, VW Bus and Mowag.
|Designation||Autophon Design.||used with||Frequency range|
|SE-206||(TR94/6)||Infantry, Light units, Engineer corps, Aircraft Trp||34,0 - 42,5 MHz (86 channels)|
|SE-207||(TR94/7)||Mech Trp (armoured vehicles), Engineer corps||41,5 - 50 MHz (86 channels)|
|SE-208||(TR94/8)||Artillery, Military Police||27,9 - 35 MHz (72 channels)|
|SE-209||(TR94/9)||Air protection Trp, Fortress Art., Anti Aircraft||23 - 28,8 MHz (60 channels)|
A main accessory is the Power Supply SG94, all necessary heater and anode voltages of the transceiver are generated from a 6, 12 or 24 V DC car battery. With an external mains transformer, mains operation is also possible. In the power supply, there is an integrated audio amplifier which will feed a speaker. When connected to a SG 94, the SE-206 will reach an output power of 2,5 Watts.
Further accessories are the hand cranked generator HG 94, it will generate the necessary voltages of 1,5 V (heaters), 51,5 and 103 V (HT / anode) and will increase the output power of the SE-206 to 1,7 Watts.
A mounting frame MR 94 can be attached with the mounting frame rack MRG 94 on a vehicle chassis, it consists of a support of of the power supply and a drawer to store spares and the necessary tools.
The remote operation unit FBA94 permits to control a SE-206 transceiver over a maximum distance of 10 km over field telephone lines; the command post switch KPU94 allows to directly switch from wireless radio to telephone line communication. A big canvas bag with the long distance antenna FA83 contains all material to erect a long distance antenna, the maximum communications range of the SE-206 is 5 - 20 km.
In addition, several test instruments have been developed for the SE-206/209 wireless set family. The battery tester BPG83 is used to check the 1,5 V heaters batteries. The battery tester BPG94 can test not only the round 1,5 V heaters batteries, but also the rectangular 51 and 101 V plate batteries. The test instrument EJ83 is used to check eight important voltages in the set.
For servicing the sets, there were specific test sets according to the model number and frequency range: The test set T-105 is used by the Signal mechanic to perform the alignment and checking procedures, the positions 1-8 of the test switch are the same as in the Eingrenzungsinstruments EJ-83. The dummy load KA83 is used to test the transmitter function without RF radiation.
The transceiver TR94 comes in a olive green metal case quite stuffed with valves (17 of them) and other electronic components. All controls are placed on the small face of the set.
The dimensions of the transceiver are 237 x 91 mm (w x h) and its dephth 345 mm, it's weight 11,3 kg. A canvas bag with all accessories (microtel, similar to a telephone handset) is attached like a backpack.
With three batteries of 1,5 Volts (ALN 10001) and five HT / anode batteries of 51 V (ALN 10051) or two batteries of 103 Volts (ALN 10103) and one of 51 Volt (ALN 10051), the R.F. output power is 0,6 Watts, with the hand cranked generator or the external power supply, it will reach 2,5 Watts.
The front panel has very few controls to simplify operation: at the left, You find the connectors for the microtel (handset) and the cable from the power supply, next to it the combined on/off, volume and squelch switch. The channel selector looks like a star, the channel number is mechanically displayed in a small window next to it, when divided by ten, the channel number equals the frequency in MHz. On the right hand, You find the antenna socket and the telescopic antenna.
The transmitter frequency results in the combination of the signals coming from the master oscillator (22 crystals with 400 kHz channel spacing in the range 37,1 - 43,9 MHz) and the so-called modulation oscillator (4 crystals in the 8,9 - 9,2 MHz range) - by combining these two oscillator outputs, the set can tune a number of 72 channels.
The audio signal from the microphone is amplified in modulator valve V11 (5678) and changes the internal resistance of a semiconducter diode D5 to generate a frequency modulation of the oscillator signal.
The signal of the modulation oscillator already with frequency modulation of the speech signal is mixed with the siognal of the main oscillator (V14 (1AD4), is fed to the driver stage V15 (DL70) and the two RF output valves V16 and V17 (3B4, each).
In reception mode, the incoming signal is mixed with the signal of the main oscillator (V2, 1AK4) after having passed a first amplifier stage (V1,1AD4), so the first intermediate frequency of 8,9 - 9,2 MHz is generated. After another amplifier stage (V3, 1AK4), it will be mixed with the signal of the FN oscillator (V4 1V6, 10,55 - 10,85 MHz, 100 kHz channel spacing) and the second I.F. of 1,65 MHz will be amplified in another three stages (V5 - V7, one 1AK4, two 5678). After a limiter stage V8 (5678), the signal is demodulated, has to pass another A.F. amplifier (V10, 1AG4) and is fed to the headphones.
V1 (1AD4, RF amplifier); V2 (1AK4, Mixer, ZF 8,9 - 9,2 MHz); V3 (1AK4, 1. IF stage 9 MHz); V4 (1V6, IF oscillator and 2. mixer); V5 (1AK4, 2. IF stage 1,65 MHz); V6 (5678, 3. IF stage); V7 (5678, 4. IF stage); V8 (5678, limiter); V9 (1AD4, automatic frequency correction, squelch); V10 (1AG4, AF amplifier). V11 (5678, modulator); V12 (1AD4, modulation oscillator); V13 (1AD4, main oscillator); V14 (1AD4, transmitter mixer stage); V15 (DL70, driver stage), V16 and V17 (two 3B4, Transmitter output stage).
In the course of World War II, it became obvious, that there was a necessity for an easy to use „walkie talkie“ for tactical speech communications to be used near the frontline. First, cheaply sold U.S. sets from war surplus were used. With the FIX, SCR-608, the first frequency modulated sets were introduced in the Swiss Army. They turned out to have superior speech intellegibility, no need to use morse code and a better safety against unwanted long distance propagation.
When the american surplus sets came to an end of their life cycle and spares were more difficult to obtain, the decision was made to develop a Swiss frequency modulated VHF radio. But the development of the SE-200 (LUX) by Zellweger took more time.
So in 1953, the War Technical Dept. gave an order to develop a new transceiver for portable and mobile use for the infantry and motorised troops. In 1954/5, Autophon could already present a working prototype of their SE-206 (partly based on the rotary channel crystal drum as found in the SE-101) and won the contract for a first production run: these sets arrived at the troops for testing in 1956/7. After the immediate success of this transceiver, around 9'500 sets of the types SE-206/9 have been produced until 1959. Amongst these, there were 1965 units of the version SE-208 for a price of 3'000 to 3'500.- Fr per unit.