überarbeitet am 6.1.2015
The Large Shortwave Station G1,5K or "B-Station" was the second high power shortwave station
used by the Signal Corps of the Swiss Army.
C.Lorenz AG at Terlin - Tempelhof has developed the 1,5 kW shortwave station
with plate modulation in 1935, it has been built by the Swiss branch of Lorenz, the
Standard Telephon & Radio AG at Zürich in the years 1937 - 1943.
Stations 1 - 14: interior with the operator's desk, you can recognize the Lorenz receiver
EO 509/I at the left and the Hell equipment on the shelf above it.
G1,5 K Shortwave wireless station with separate transmitter and receiver
Transmitter (C.Lorenz / STR): 1090 - 6700 kHz
Receiver E-622 (Lorenz EO 509/I): TRF receiver
Receiver E-601 (Zellweger E41): superhet
Receiver E-627 (Autophon E627): superhet
telegraphy CW (A1), modulated telegraphy (A2), telephony (A3), Hell
pout A1 1500 W / A2/A3 500 W
trailer with station equipment, single axe trailer with three phase generator
(380 V, 50 Hz, 15 kVA) powered by 22 HP fuel operated motor
Stations 15 and above: interior with the operator's desk, you can see the Zellweger E41 at the left
side with the coil sets on top of it, the Hell printer at the left of the desk and the Hell
punched tape reader and transmitter on the right shelves.
The Large Shortwave Station G1,5K has been developed by C. Lorenz AG, Berlin, in around 1933/34;
it has been built by the Lorenz - branch Standard Telephon & Radio AG at Zürich in 1935/37.
The station got the designation G1,5K (Gross / Large - 1,5 Kilowatts - K / Shortwave) with the Signal Troops
and "B Station" with the Air Force Signal Command.
|The three stage Lorenz transmitter can be tuned in four ranges from 1090 - 6700 kHz,
variometers are used for antenna tuning.
In the transmitter the following valves are used: in the driver stage a RS337, in
the intermediate stage two RS377, in the output stage two RS329g, in the modulation and
keying stage two RS382 and three rectifiers RGN2504, in the microphone voice amplifier
stage two RS282 and three RE084k.
The transmitter covers the frequency ranges 1090-1930 / 1930-3430 / 3430-4830 and 4830 - 6700 kHz,
dial accuracy of the analog dial is 1 %o, a luminous crystal is used for calibration
at 3000 kHz.
The transmitter output power ist 1500 Watts CW and 500 Watts in modulated telegraphy
The receiver used in the early years with the stations no. 1 - 14 was the two tuned circuit
TRF All Wave Receiver EO509/I made by C.Lorenz AG. This battery
valve receiver turned out to be unsensitive on shortwavex and made reception in Hell mode
extremely difficult. So it was replaced by the All Wave Receiver "Uster" / E41
in stations with number 15 and above.
In the document folder "Funkstationen der Armee" is mentionned, that stations number 1-6 and
the "B Stationen" of the Air Force were equipped with two Autophon Allwellenempfängern E44
and the stations 15-28 as well as 32-34 with two Allwellenempfängern "Uster" / E41.
In 1956, the station G1,5K was improved with the new receiver Autophon E-627
and the Telecrypto 53 / ETK
combination for automatically encrypted teletype operation. The transmission quality often
suffered from synchronisation errors which caused decryption faultsm this was not really
improved after the receiver was replaced by the Siemens E-311 / E-645.
Radioteletype operation with automatic encryption became much more reliable after
the introduction of Krypto-Funkfernschreibers 58 with it's capability of automatic synchronisation.
In the early years, not only telegraphy and AM telephony but also radioteletype
Hell, in fact a radio-facsimily transmission mode, was intended to be used. The
"Hell" printer developed by Siemens Hell-Schreiber
prints out a text directly lisible on paper tape. As the shortwave communication quality strongly
depends on propagation conditions, using the Hell mode was quite challenging for the
signalmen operating the station.
So even during World War II, the decision had been taken to abandon the Hell mode
and to use high speed telegraphy instead: The station G1,5K saw the introduction auf
automatic high speed telegraphy Moser-Baer.
A major breakthrough with higher transmission speed was the introduction of the
radioteletype system ETK developed by Dr. E. Gretener AG
in the years 1955/56. With the ETK teleprinter and the Telecrypto 53
ciphering machine, even automatic encrypted radioteletype communication was possible.
The things really were made easy with the introduction of the KFF-58,
the crypto radioteletype machine developed by Gretag with automatic synchronisation.
The station G1,5K is powered by a four stroke fuel motor operated generator
providing 15 kVa three phase power, this was installed on the "machine trailer".
© 15.1.2013 Martin Bösch