Detailed Historic Documents
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HISTORY OF WEHRKREIS 1940 – 1945
This is the first of many documents including modern maps and rewritten text with added information.
The reworked documents are in pdf format and the maps are
JPG's
The Wehrkreis Network was first intercepted at Fort Bridgewoods near Chatham, by the same service under one of its previous names. They were to move from Fort Bridgewoods to RAF Chicksands in 1940 in becoming the Special Y Group (SYG) on the way, then the final move to Beaumanor in 1941 saw the SYG become the War Office Y Group, (WOYG). The interception of the Wehrkreis Network is acknowledged as a formidable step forward into the modern world of Signals Intelligence (SigInt). Through the painstaking work of each of the different disciplines a total picture of what, where, when and who, was not only maintained but also accurately predicted for the whole of the war period. For the first time signals intelligence was becoming the recognisable discipline of today.
Through each of the periods new techniques were developed and by the end of the war, a streamlined organisation had evolved capable of predicting the callsign, frequency, time, location and radio finger printing the transmitters almost instantly. The intercepted messages were passed on to Bletchley Park for the military intelligence operation to continue on through to the code breakers and back out to the commanders in the field, of course the information gathered was also fed back into the system to help with further enhancing the processes within the Y Service and code breaking systems.
The system of
Wireless Telegraphy (W/T) between Headquarters (HQ) of the Military Districts
into which Germany was divided up to the end of 1940, has already been clearly
set out in a report “the Wehrkreis W/T communication system” issued from
Fort Bridgewoods on the 15th January 1941. Briefly however it may be
said that for medium frequency purposes the whole of Germany was divided into
three large W/T areas (FUNKBEREICHE), a North-Eastern, a North-Western and a
Southern area all of which were controlled by OBERKOMMANDO DES HEERES (OKH) at
Berlin. In addition two stations one in Denmark which worked to Berlin and one
in Rumania which worked to Vienna were also connected to the organisation.
OKH at Berlin and the three W/T areas each had their own
receiving medium frequencies, Berlin however not only received on it’s own
medium frequency of 370Kcs, but
also transmitted on it at fixed hours Broadcasting messages to be picked up by
all stations and also assisting communication between stations by indicating to
one station that another was attempting to communicate with it. Communication on
the high frequencies was somewhat different, there was no distinction
between areas. Each station had own individual receive frequency which
changed daily. Furthermore transmissions were preceded by one call only, that of
the sender, the identity of the addressee being sufficiently clear from the
frequency used.
The callsigns used were taken from a book (known as the
“DOG” book), in which there was a series of callsigns, each series having
the callsign for each day of the month. These series or “Columns” were
allocated to individual stations and as, at that time, a copy of the book had
been captured. It was possible to keep a track of each station from day to day.
The callsigns were found to repeat for corresponding dates of each month.
The medium frequencies remained constant, and it was
found that individual high frequencies assigned to each station daily,
reoccurred on corresponding days of successive months. It was thus possible to
forecast with confidence the daily frequencies used by the Wehrkreis
organisation as a whole, a fact that was of utmost importance to intercept
stations.
From 1940 onwards the Wehrkrais network underwent several changes and it is for this reason that it’s history is being reported in periods as under.
Period 1
autumn 1940
to
December 1941
Period 2
February 1941
to
December 1942
Period 3
January 1943
to
May
1944
Period 4 June 1944 to March 1945
Period 5 April 1945 to May 1945
The rest of this document is available for you to read by contacting the club. A colour map has been produced to help with identifying the geographical locations and frequencies used by each of the stations for each of the 5 periods.
GHQ Netz Document coming soon Vulture coming soon The "E" Book coming soon