Page 122 - The Secret War in the Italian front in WWI (1915-1918)

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

6.3 TELECOMMUNICATIONS SECURITY

securITy objecTIves

It is obvious that the best defence against enemy Communication Intelligence is achieved by limiting
as much as possible the use of telecommunications media, for instance by avoiding the use of the
telephone indiscriminately and adopting radio silence every time that alternative communication
channels are available. Therefore, the success of communication intelligence operations depends
significantly on the enemy’s communication strategies regarding the size and type of traffic,
transmission norms, etc. The Italian and the Austro-Hungarian armies adopted, during a large part
of the war, significantly different criteria in their radio communication management.
Since it was impossible to completely exclude telecommunications, which resulted to be
indispensable in many circumstances, all armies tried to adopt procedures presently encompassed
under the Communication Security discipline, trying to ensure a) the communication systems
physical integrity; b) the protection of transmission channels and c) the protection of contents.
Physical security measures, systematically implemented during WWI, include surveillance of
telegraph and telephone lines and of radio stations as well as adoption of methods suitable to
prevent the capture of equipment, instruction manuals, ciphers, and other classified documents
regarding telecommunications.
Transmission security consists in defending transmission channels from interception and interference,
while protection of contents requires the application of cryptologic or of steganographic techniques.
In telephony, afrer the first fortuitous listenings of enemy communications, it became evident
that the same thing could have happened also on the opposite side. Therefore, all armies tried to
increase the telephone transmission security modifying the telephone lines structure to prevent
eavesdropping, with not always successful results.
Different methods and tools to increase the transmission security of radiotelegraphic transmissions
were also tried during the war. Yet, in practical terms and with the available technologies, the
means utilezed for this purpose often proved to be not easily operable and/or scarcely effective.

aTTeMPTs To IMProve radIo TransMIssIon securITy
Radio vulnerability to interceptions mainly originated from the difficulty to implement field
directional antennas which could avaoid the transmitted waves to be broadcasted in every direction,
including enemy posts. The increased safety of communications through greater directionality of
antennas was a goal pursued with all the available technical tools, but impaired by the difficulty
of increasing the size of field antennas beyond certain limits and by the low radio frequencies
generally employed at that time.
During the early months of 1916, while serving on the front line as a lieutenant of the Engineering Corps,
Guglielmo Marconi identified as a means for achieving high directionality with relatively small-sized
antennas, the transition from the long and medium waves used until than for field communications,
to metric waves (VHF or Very High Frequencies). Marconi carried out the first experiments in the
hallway of the hotel in Genoa where he had been staying to recover from an illness. He later repeated the
measurement on a larger scale in Leghorn and then in England, but radio technology was not developed
enough for radical innovations of that kind. In fact, the higher frequencies tested by Marconi where
systematically employed several years after the end of war. picture 6.10.
In addition to the difficult increase of antennas directionality, it was hard to reduce the transmitted
powers, also because the field stations connecting Army’s high commands were often deployed at

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