The German agencies responsible for monitoring illicit radio transmissions were the Radio Defence Corps of the Armed Forces High Command – OKW Funkabwehr and the similar department of the regular police – Ordnungspolizei. Both agencies operated in the occupied countries but they were assigned different areas.
These agencies not only monitored the agents’ traffic but in many cases they were able to locate the site of transmissions through D/F (direction finding). In such cases the radio center was raided and often the operator and his cipher material were captured.This cipher material was then used by Dr Vaucks agents section to identify the crypto-systems, solve them and decode the traffic. This section, headed by Dr Wilhelm Vauck, was originally part of the Army’s signal intelligence agency OKH/In 7/VI but worked closely with the Radio Defense Corps. It was established in 1942 and by the end of the year two-man teams were detached to regional Aussenstellen in Paris, Marseilles, Lyons, Prague, Oslo, Vienna, Brussels. In late 1943 the entire department was moved to the OKW Funkabwehr.
According to postwar reports they usually had success with a system if it had been physically compromised. However in some cases it was possible to solve enemy systems cryptanalytically.Now I’ve tried to find more about the work of dr Vauck but I’ve hit a brick wall.
Still there’s more than one way to skin a cat…Here is a report of Referat Vauck for February 1944:
Google translation with corrections by Frode Weierud:Referat 12:
In the O.U. Zinna were processed the traffic of the LCA network with the agent callsigns QYZ, WOS, RCJ, SFY, PYM, ROY, SIA, OIN, REF, furthermore the lines 9171 (SAM), 9811 (VY, RQ), 175 (SPE), 9853 (RGE ) and 9815 (without Ag.Z.). Among the latter, cipher documents were received from the colleagues detached to the branch control centre in Paris (Aussenleitstelle Paris). Further, in the case "Normandy" address material that turned up was deciphered and the courier cipher (Playfair) was reconstructed. 8 courier letters of the Belgian ND (Nachrichtendienst — intelligence service) and further address material were deciphered (ez.mäßig — entziffungsmäßig gelöst).The department itself deciphered 372 messages from the LCA network. In the ongoing 8 Gv plays (Gv — Gegenverkehr, counter traffic, radiogame) in the region of Paris 101 messages were deciphered and enciphered.
The processing of line 3014, Paris-Moscow, has been completed after decryption of the last 19 messages.No report has yet been received from Brussels about the work of Uffz. Richter and Miersemann, who have been detached there. Also from Lyon and Marseille are there still no work reports.
During this month 262 messages from the Czech MBM network were broken (decrypted). By analyzing the solution it was possible to secure further parts from the presumed book used as a cipher key.65 messages of the Rote Drei were decrypted, so that now 382 broken messages are available. The order for a cipher change — transition to fixed mixed Caesars — was detected in mid-December. The change of the cipher key book happened already at the beginning of August 42. The key for the Sissy-messages resulted in the solution of a message from December 42.
To understand the incoming but still unresolved traffic arriving at Ag WNV / Fu a cooperation was started with the responsible person there, Uffz. Kegel.Total output of the unit in the month of February 819 messages.
Notes:Regarding the ‘Normandy’ case according to Wilhelm Flicke’s ‘War Secrets in the Ether’ vol2, p244
‘Normandy case’ (French Section) – When German radio defense picked up two agents in Montlucon on 1 May 1944, an Englishman, Major Southgate, fell into the net. Since January 1942 he had built up in France in the areas of Tours, Poitiers, Limoges and Toulouse special transmitting groups and had organized numerous parachute deliveries of arms and explosives. A study of the captured material enabled the Germans to identify 62 places used for parachute drops.The LCA net refers to Western agents. What agencies were using the call signs mentioned in the German report? SOE? Free French? Poles? All of the above?
Some of the same agents callsigns appear in the report PWIS(H)/KP/694 - 'Report on Interrogation of PW Gefr WEIGEL, Fortunat - German Wireless Intercept and SD Activities' – May 1945