Air Raid Warning Communications System
überarbeitet am 13.12.2010
An "Air Raid Warning System" similar to the "Alert and Warning Net" of the U.S. Army
has been installed after 1961. As standard high power transmitters and receivers
E-627 have been in use, without capabilities of selective call or muting of the
receivers between the messages, many messages were missed because the receiver's
volume was turned down the whole day long ond the operators missed the scheduled
The shortwave transmitter S-510 has been used for long range communications in the
"Swiss Air Raid Warning Network" operated by the anti-aircraft troops, the receivers
placed in the command posts usually were muted and were called by a selective call
system which could adress eight different receiver groups or all receivers at
the same time. Messages could be transmitted in AM or single sideband mode.
The complete communications system consists of a transmitter control unit BG-510,
connected to the remote transmitter site via field telephone lines.
The speaker's microphone is connected to the transmitter control BG-510, from there the frequency and the receiver group address is selected. The transmitter is tuned to the operation frequency within a few seconds fully automatically.
The receiver E-646 also constructed in a similar design by Zellweger, Uster,
can be powered from batteries or mains and is equipped with an external speaker to
be placed in the command post room. It can be run from batteries over several
days, when it is in muted operation.
© 13.12.2010 Martin Bösch