Trunked Radio Station SE-225
überarbeitet am 10.1.2013
For a project to replace the very commonly used Swiss Army wireless stations
SE-206/9 and the vehicle stations SE-407/11,
a call for projects was made in the sixties. United as a consortium, the
three major Swiss manufacturers Autophon - Brown Boveri and Zellweger
started the devlopment of a new station in 1966. As the requirements made by
the Signal's Command in Bern were very high, the whole project got to a stop
and had to be relaunched in 1972, only after several years, the first sets reached
the prototype stage.
The SE-225 is a trunked VHF radio system with frequency modulation which is
intended to be used as manpack radio, on vehicles or in fixed buildings or
The VHf radio operates in the 30 - 87 MHz range, 76 (19 x 4) channel bundles
with a bandwidth of 3 MHz kan be used, each with 30 channels with 100 kHz channel
spacing. Using the selective call capability, 1 up to 9 members of a network
can be called selectively.
A control unit, the Bediengerät BG-225, is an important part of the system:
it's a telephone like handset with an integrated numbered keybord which is
used to control and to program the radio and to enter the key used for voice scrambling.
The important keys are the "Talk" key to start a transmission which acts as
PTT (push to talk key), the key "F" (FREE) which will and a transmission,
the key with the key symbol to enter the transmission key for scrambling/unscrambling
and the key with the triangle, which indicates unscrambled / unsecure operation.
The Se-225 has an internal voice scrambling function. The key consists of 12 digits, four of them are already stored in the set and the other 8 digits have to be keyed in using the control unit. The key saved on memory channel one is the main key in use, when no other key has been entered.
In the "manpack" variant, the transceiver is mounted on a carrying rack TR-225
together with a lithium battery or an accumulator. With the batteries, the complete
set has a weight of 13,0 kg.
As said before, the set can be powered from a lithium battery in the battery compartment BAF-225 or a NiCad-accumulator in the accumulator compartment AKF-225, as an alternative, the set can be run from a 12 or 24 Volts vehicle battery of for fixed use from a NG-225 mains power supply.
The SE-225 can use different antennas: the 1,6 m rod antenna MA-225 for use as manpack, a 1,9 m vehicle antenna FZA-225, or the long distance antenna FA-225, mounted on a eight segment glass fibre mast with a height of 10,8 m.
A high power RF amp LV-225 will increase the set's output, it can be regulated from
400 uW / 0,4 W / 4 W and 40 Watts.
A remote control unit (Fernbetriebsausrüstung FBA-225) gives the opportunity to control the SE-225 radio over field telephone lines over 3 km, there is a provision for a service telephone communication from the remote to the transmitter location. A RS232 interface allows data transfer of up to 1200 Baud.
There were prototypes of an on-board intercom BVA-225, with an onboard switchboard BZ-225, junction boxes and a noise garnish LG-225, but all of this equipment has not been introduced with the troops as the mechanized troops had already introduced the SE-412 / VRC-12 radio and there was no need for on onboard-use with the Air Force troops.
The equipment shown makes part of a Swiss private collection
© 10.1.2013 Martin Bösch