Page 258 - The Secret War in the Italian front in WWI (1915-1918)

THE SECRET WAR ON THE ITALIAN FRONT IN WWI (1915 – 1918)

enemy lines, at the beginning of 1917 the Italian Air Force technicians designed a 180 W station
called T.Av. with a range of up to 60 kilometres. Three Italian companies were entrusted with its
industrial production (picture 11.15) .
81
Thanks to the space and energy available
on board, airships could carry transmitters
of higher power than planes; moreover,
reception of ground stations transmission
and some kinds of radio navigation aids
were also possible thanks to silence in flight.
The risks of sparking fires originated from
the contemporary presence in the nacelle of
spark devices and hydrogen, was avoided
by adopting the valve transmitters tested
in 1917 by Guglielmo Marconi on Italian
and English airships. A piece of transmitter
equipment built in the workshops of the
Army and known as Onde Persistenti per 11.16 Airship Continuous Wave Device. Top right: the
Dirigibili, OPD (Continuous Waves for transmitting valve (ISCAG Library)
Airships) is shown in picture 11.16.
The enemy put a great deal of attention on every radio transmission connected with aeronautical
services, which required protection using special ciphers. Since the airborne observers transmitted
the collected information to the ground under difficult operating conditions often due to enemy
fire, the simplicity of dispatches and their encoding was of primary importance. Therefore, the
cipher system intended to support Artillery and Infantry consisted of table on a single page,
containing a match between current terms and one or two-letter code words. Also coordinates of
simple squared maps could easily be send by air observers. Not surprisingly, the Austro-Hungarian
analysts interpreted these unsophisticated dispatches with equal ease, as the Italian did for those
of their airborne operators. On the other hand, the information gathered by the air observers were
usually of such nature that jamming the transmission frequencies of enemy aircrafts for impairing
reception resulted to be, in fact, more useful than interpreting dispatches.
The C5, adopted by the Italian air force in the spring of 1917 (picture 11.17) can be considered
one of the most complex codes for radiotelegraphic correspondence with airborne radiotelegraphic
stations, mainly aboard airships . Its service timeframe emerges from an apparent reference to the
82
C4 included in the Instructions.
The C5 is a two-part code and uses code groups of two or three letters chosen in the abbreviated
alphabet of 17 letters, customary for service ciphers. From the first page of the coding part shown
in the picture, the distinction between the primary groups shown on the left and the secondary
groups on the right results evident, with the regular repetition of the first letter in the groups on the
right. The groups were sent as such or, like other service ciphers, combined to form sets of four,
five, or six letters. No information was found in the Austro-Hungarian sources about this code.

81 The companies are: Craveri of Turin, Fratelli Marzi of Conegliano Ligure, and Campostano of Milan. Some components
of the 200 W field station are included in this equipment, such as the disc spark gap.
82 Library of the ISCAG, coll. XXXI A, no.11129. The code partially shown in the Picture, formerly belonging to the Chief
Inspector of the STM is among the papers handed over to the ISCAG by Luigi Sacco in 1947 and contains handwritten notes.

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