When the Swiss Army called for offers for a mobile high power shortwave transmitter
in 1949, only Telefunken Zurich made an offer, in 1954, two prototypes were available
for testing and a preliminary series of 15 stations has been built until 1957.
After Zellweger had presented their single sideband transceiver SE-222 which was much
smaller and could also cover the whole country with telephony and encrypted radioteletype,
no further SE-406 stations have been acquired. The remaining 15 stations stayed in service
The station SE-406 came with a shelter containing an operator's room on a truck chassis Saurer 2 CM,
it has one transmitter and two receiving posts in the front of the shelter and
an operator's position for encrypted radioteletype transmissions in the rear part.
In the front part of the operator's room, you find the transmitter Telefunken Ap 3062, an automatic
antenna tuner Ap 3063 with five preset channels and two receivers Autophon E-627.
The transmitter Telefunken Ap 3062 has three stages and plate modulation.
It can be tuned to any frequency in the 2 - 26 MHz range, there is also the possibility
for crystal controlled fixed frequency operation on five preset channels. The output power
of the transmitter equipped with U.S. tubes is 400 W in the mode Telegraphy A1A, and 300 W in modes
A2A and telephony A3E, there is an adaptor for F2B radioteletype operation.
The semiautomatic antenna tuner Ap 3063 kann be pretuned for five preset channels
for continuous coverage, it has to be tuned manually.
Two superhet receivers Autophon E-627 are the standard receivers of the station,
they can also be used from the vehicle battery by use of a vibrator power supply.
The station has initially been equipped with encrypted radioteletype technology,
the 14 segment radioteletype machine ETK made by Gretener is a quite unique design,
on contrast of standard radioteletype transmissions using Baudot code, the message
has a better readibility under poor conditions: when parts a letter are omitted, you might
still recognize the letter. The ETK can be operated in connection with the Telecrypto 53
The station can be powered from mains or from a fuel operated 400 V, 50 Hz, 7,5 kVA generator.