Page 239 - The Secret War in the Italian front in WWI (1915-1918)

CHAPTER ELEVEN

On the opposite side, as already mentioned, the first experimentation of the Austrian radiogoniometry
system began only in January 1917 and, in March, the listening stations received the devices
and acquired full familiarity with them around June . At the same time, the Austro-Hungarians
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increased the number of direction finding stations also in the maritime sector after having stumbled
upon a document in the summer of 1916 which made them aware of the state of progress of the
Italian Adriatic radio goniometric network.
For the largest part of 1917, until the preparation of the Austro-German offensive in October,
the interceptions of Austrian field stations at the Italian front became infrequent, due to the strict
radio silence imposed by the Headquarters, while some Austrian stations continued to operate in
the Balkan peninsula, particularly in Montenegro, Serbia, and Albania. Their regular interceptions
provided useful information and material to the Italian Cryptographic Unit.
In addition to the Austrian naval and field stations, the Italian interception stations focused on
fixed Austro-Hungarian stations (Budapest, Castelnuovo di Cattaro, Durres, Lošinj, Rijeka,
Pula, Sarajevo, Sibenik, Timisoara, Vienna, Gratz, etc.), German stations (Berlin, Cologne,
Hanover, Nauen), Bulgarian stations (Philippopolis, Jamboli, Sofia, Varna), and a Turkish station
(Constantinople). Enemy high transmitting power plants such as the German one in Nauen
committed to transoceanic communications, and medium transmitting power stations, such as
those in Vienna, remained constantly under the lens of the Italian interception service.
Traffic analysis provided a wealth of interesting information. For example, the large number of
encoded dispatches that Vienna, Pula, and Budapest exchanged with Barcelona (picture 11.2) was
the result of the strong diplomatic and commercial relations between the Central Empires and
Spain. These communications raised large interest from the Entente Allies, since they probably
hid something related, for example, to underwater warfare .
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anTIsubMarIne warfare

The unlimited submarine warfare started by Germany on 1 February 1917, was also extended to
the Mediterranean Sea where German submarines operated from their bases in Pula and Kotor. The
tonnage of ships directly sunk by the ‘Pula Submarine Group’ or by naval mines it laid, increased
in the months that followed, with a peak in April when, in the Mediterranean alone, the total loss
of allied vessels amounted to more than 250,000 gross tonnes (GT), of which less than 10% due
to Austrian submarines.
In the following months, this number gradually decreased, to approximately 35,000 GT in the
last months of the war, thanks to the countermeasures put in place by the Entente, such as the
development of radio interceptions, localisations and cryptoanalysis carried out in a coordinated
manner by the Italian, British and French. We are not attempting to recount here the tremendous
efforts made by the Allies Radio Intelligence in the Mediterranean, but just reporting some of
the contributions of the Cryptographic Unit to anti-submarine warfare in the first half of 1917, as
allowed by a report written by Luigi Sacco in July of the same year and by some information
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included in the R Section logs.

20 M. Ronge, Der Radiohorch, op cit., p.19, 21.
21 Codroipo RT Office, Relazioni sul servizio d’ascolto, op.cit., Jul. - Aug. 1917. In August alone, 500 messages were sent
from Pula to Barcelona, of which 100 were encoded. In the opposite direction, out of 310 messages, 100 were encoded.
22 Intelligence Service, Section R, Notizie Riassuntive sui Sommergibili Nemici, (Summary news about enemy submarines),
Rome, 27 July 1917, ISCAG, Coll. 223. The copy kept in the ISCAG archive is limited to April, May, and part of June and some
of the last pages are missing. From the Section R logs, it appears that on 1 April Luigi Sacco had sent another report entitled

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