Radio in the Gehlen Organisation
German Intelligence after the war started under US control using ex-Nazi
intelligence Officers at Oberursel near Frankfurt in a US Army camp. Early spy transmissions were made from there in 1946 to German intelligence people such a' "Werewolf" units left in the USSR & Eastern Europe it was depressing and resembled a POW Camp so the decision was taken to move it to Pullach in Bavaria.
Many agents already had their homes and families in Southern Germany and Oberursel was insecure as well as overcrowded. Pullach offered space and greater privacy so was considered ideal for Bureau Gehlen, and later the BND's purposes.
The "Org" moved to Pullach in 1947 into an estate which had previously housed Hess's staff, Dachau workers, plus Bormann's staff later on- The US spent $3 million to convert Pullach with a modern communications centre and refurbished accommodation plus large underground bunkers 3 floors deep.
lt was under cover as the "South German Industries Utilisation Company", and over 10 years $200 million was provided by the US. Numerous offices were established all over Germany under commercial cover and were usually known by 4 digit number codes. A counter-intelligence office was established In Munich-Straubing and the "The Org" as it was known to insiders grew steadily using commercial firms as cover to smuggle transmitters to agents in the Last. these agents were known as "V-men' (Vertrauens Mann) or "trusted men" who were mainly German ex-POW's from the USSR or from the German SD + SS Army or Eastern Bloc refugees.
Over 60 schools were established for agents but the agent handlers never became over-familiar with agents. Much trouble was taken to protect agents using an ABC code In CW. This involved warning signals being sent and repeated with the agent's code number e.g. 364A would tell him there was danger and to go into hiding. 364B meant radio silence and to go into hiding before preparing to leave. 364C meant contact the Head 'W-Mann" via courier or deaddrop.
The system of taking agents off air temporarily saved many lives such as Heinz Fink who operated a radio in Potsdam for 10 years before being killed in 1962. He was placed on a sleeper roster for months as was Franz Pankraz who worked at the Soviet radio station at Koepenick for 15 years. Much infiltration of radio operators was carried out in the early years as prior to 1948 movement over the inner German border was easy and they survived in pace for many years. One was Leopold Muller who survived at the telecommunication centre at Rostock as an engineer responsible for transmitters at Wittenberg, Schwerin and Ludwigslust lie provided details of DDR radio nets with other WTO countries. His one-time-pads had 6 columns of 5 digit groups and were 1 inch by 2 inches. It was too difficult to see on a photograph how many groups were in each column.
Radio was the mainstay of the Org after 1956 when East-West travel was restricted and in 1%l when the Berlin wall was erected. Radio Free Europe and other "private" stations in Germany were widely and successfully used for sending coded and musical signals to agents. Gehlen had a powerful transmitter near Pullach and another at Stocking near Munich A third was operated by the Frankfurt/Cologne regional branch of the Org. It was common for Soviet and DDR interceptors to RDF the transmitter then Pullach would order radio silence This worked both ways as the US CIC and the Org used electronics supplied by the FCC to catch Eastern agents.
1952-3 saw the Berlin uprising and radio rather than couriers was used for communications It was necessary to train a large number of radio operators using small transmitters with low output power. These modern sets supplied by the US were easy to conceal and smuggle across borders Some people were brought to West Berlin for training in the use of the radios and numerous operators were sent into the East. Gehlen bad a transmitter in West Berlin and in Munich; an emergency receiver was tuned to prearranged wavelengths and hidden amongst the aerials at Radio Free Europe Another receiver was installed at Pullach to receive the flow of signals from East Berlin.
The DDR Ministry of State Security thought in 1952 that there was one WIT operator for eleven or more West German agents. By 1953 they believed that the ratio was 1:7. The following estimate was produced by DDR security in 1963 for radio operators sponsored by Gehlen and working in the East, along with their estimated locations:

LOCATION 1953-55 1956-63
East Berlin 17 40
Chemnitz 17 20
Leipzig 32 18

It was not felt to be a good idea to burden agents with both a transmitter and collection duties. they would collect information then place it in a dead letter box before a courier would take it to the radio operator. Very able operators were recruited by "Hochberg' and "Paulberg' usually from amongst the ranks of ex-SS and German Army operators. One was Joachim Koch who had sent trial signals and received "blind' broadcasts from Stocking. He had a 12 Watt transmitter which was tuned to the Frankfurt and Stocking receiver stations. The signals were never above 16MHz and the emphasis was on strong signals over a long distance. He had three transmitters and disguised his aerial as a washing line, and mainly concentrated on airfields and troop movements, until his detection and execution. The largest network was called 'North-East' and was still intact in 1971 providing information on railways, bridges and airfields. One agent made 68 crossings of the East/west German border. later, transmitters were stored in hermos flasks which were provided by the US.
Numerous posts were established by 'Paulberg' all over the DDR and a 1956 DDR Security map showed 47 places where Gehlen radio posts were operating and many more were set up after this. The US began supplying burst transmitters with a maximum transmission time of 45 seconds and a rate of 5,400 signs per minute by electronic compression. These needed simple instructions over 1-2 days, whereas manual CW operators needed 8 weeks and usually only managed 80 signs per minute
The BND later spent 500,000 DM to replace the radio equipment of the V-men.
Many sets were devised with remote control so operators could make a quick escape if necessary. Similar operations were mounted on a limited scale against the USSR and other communist countries but such deep infiltration operations were rare.
Many agents were equipped with MW receivers which had a conversion device to turn it into a IIF transmitter broadcasting on 3-5 MHz. Not much power was needed because the signal only had to cross the Inner German border. For operations in Armenia and Georgia a relay station was set up in Tehran and another in Stockholm for operations in the Baltic states during the 1950's.
Gehlen was almost dismissed when French Security discovered that be had been spying on the UK and France and his agents had collected information on holy loch, Thor sites and the Ballistic Missile Early Warning Station at Fylingdales, Yorkshire, England.

A recent book published in Germany "Top-Spione' by Guido Knopp provides some excellent background information and direct references to the BND's number station activities. The book covers six biographies but perhaps most interesting to numbers monitors is the case of Werner Stiller. Stiller contacted the BND via a relative of his West German girlfriend. He was later to receive a letter, information about radio frequencies code charts and 10 SAE's with pre-written letters to addresses in the FRG - and some invisible ink of course The one thing that was missing was a short-wave receiver that could be tuned to 3.7..4.0 MHz 'in that range the BND broadcast his messages'. So his girlfriend went through to East Berlin and managed to obtain a "Telefunken International 101". The BND broadcast daily under the headers 688 and 226. To ensure that the messages were received they were broadcast at different (fixed) time slots. The broadcasts started with the Wessel-anthem, the interval signal of the BND, so named after Gerhard Wessel, the president of the BND at that time. A female voice spoke. 'Esliegen Mitteilungen vor fur.. 'the group count was given. Receiving and decoding the messages was the task of Stiller's girlfriend Helga Miehnowski. Therefore she always had to carry the radio with her. She later said that it would have been better if she could have used a headphone but the GDR-headphone-plug did not fit into the West German radio. It was difficult to understand the broadcasts, sometimes she had to listen more than once, because the signal strength varied and also due to interference. The broadcasts were in 5F-groups and if you missed one it was pointless to continue listening. For every group there was a group on the one-time-pad, which had to be subtracted from the one on the radio. Once they had the correct numbers these had to be used with a codechart to read the actual message. The reception and decoding of a message could take ~5 hours. The messages mainly comprised of questions about the identity, the importance and the knowledge of their new, unknown contacts.