VHF Signals Monitoring Company General operations of the VHF Company procedure created in 1943 had a geographical component. The diagram represents the concept of direction finding units enclosing a target across featured geography, i.e. topographic area. In an area where the foreign agents were suspected of being located, a unit would conduct long-range direction finding operations using
goniometric stations that would form a triangulation
azimuth. The central battalion with radiating communication spokes could triangulate on a war theatre, a city, town or village. This is represented at the top left of the diagram. Once the long-range DF units had formed a rough azimuth, defining an area location for the agents, represented by the bottom left diagram, a short-range DF platoon would move into the suspect's area and this is represented by the bottom-left diagram on the left. Once the short-range DF was established it would locate the suspect, represented by the bottom right diagram. Operators with Suitcase DF units would them move into the area to triangulate on a particular apartment or house. The VHF Signals Monitoring Company differed in operation and technique from the HF Signals Monitoring Company, as
Very High Frequency (VHF) waves propagated differently from
High Frequency waves. The existence of a
Skywave was irrelevant to the problem of interception and DF in the case of VHF, as the work concerned itself exclusively with the quasi-optical waves which radiate from the source according to line-of-site. Radio waves in the VHF band propagate mainly by line-of-sight and ground-bounce paths. The definition of VHF meant
wavelengths between 1 metre and 10 metres, at a frequency of between 30
MHz to 300
MHz. However, the Funkabwehr often ran transceivers that passed the 10-metre limit by as much as 2 metres. It was known by the Funkabwehr that the shorter the wavelength, the more the wave behaviour resembles that of visible
light in the manner of
electromagnetic radiation. As there had to be a direct
line-of-sight between the control station and agent station, the following conditions could be expected in a VHF agent operation: • Immediate vicinity to the coast: Agent positioned on the coast, or on a high point of land in the vicinity of the coast, with an Enemy control station on an island occupied by the enemy, or on board a ship.
Intercept and monitoring station The monitoring stations had the following duties: • To carry out general search services on Radio Telegraphy and
Wireless telegraphy. When traffic was picked up, the monitoring station determined whether it was agents' traffic. In all situations in which it was not completely clear whether or not it was agents' traffic,
tape recordings were made of the traffic and a
linguist transposed it to a paper format. • Current monitoring of traffic known to be from an agent by reason of information given by the analysis section. Should a monitoring station pick up not only the agent control station but the agent station itself, where the monitoring station had a DF unit available, then a DF bearing was taken immediately. The VHF intercept stations used the following equipment: • 2 radio intercept receivers (Type V) - • 1 SADIR VHF DF Receiver - This was a captured French unit. • One of between-band receivers
Fanò and
Samsos FM or AM receivers. They were considered too scarce to give to all soldiers. • VHF receivers, captured from eliminated agent stations. All units were eventually equipped with these. • Recording device to record Radio Telegraphy traffic. • HF transmitter for communication to company HQ. • Additional auxiliary equipment. Each team consisted of a team leader, who was a W/T operator and message centre liaison, three linguists and three intercept operators.
Close range DF platoon Organisation A VHF close-range DF platoon consisted of: • Two or three DF teams equipped with VHF DF sets of
Type D, also an HF transceiver to communicate with headquarters. The Belt
Direction finding unit was a small, flat apparatus which can be worn as a belt under a jacket or coat without being noticed. The power supply is small enough to be carried in the trousers pocket. The DF unit
antenna consists of a thick, rubber insulated cable. This comes out of the DF apparatus along the right hip of the carrier, passes under the right arm and over the back of his neck, then under the left arm, down to the left hip. Operations conducted with the belt DF unit could only be carried out in the case of distances under 400 metres. Only direction could be determined, but it could not be sensed, possibly resulting in a 180° error. In this manner, the DF technician could switch back and forth between agent and control with one hand and could easily determine, at any given time whether they were unable to hear the agent station for the reason that the control was transmitting, or whether the agent was transmitting and they could not hear them as they were too far away. Immediately a bearing was discovered, each DF team reported it to all other DF teams in the area via HF transmitter. In the vicinity of each VHF DF one intercept search team was posted and another placed to the estimated location of the agent's transmitter. In order to accomplish results, the bearings taken had to be exchanged by all stations within 3 minutes after the agent began transmitting. The immediate vicinity was classed as the area in which the use of very close-range DF apparatus was applicable for use. Such a team consisted of a DF operator and an assistant. Before the operation they would familiarise themselves the details of the neighbourhood landscape where the operation would take place. The assistant had the following duties: • Act as a lookout and watching for suspicious people, proceedings and radio antennas. • Protection for the team Very close-range teams used work-belt DF sets and different kinds of suit-case sets to establish bearings at very close range. The bicycle DF consisted of a DF
aerial and intercept receiver concealed in the bicycle frame. If the agent who was betrayed by their traffic was considered suspicious, then everybody who was considered a suspect in the building would be arrested under all circumstances. If the very close-range operation went off according to plan, then the elimination of the agent was carried out in whatever manner the Funkabwehr or the
Reichssicherheitsdienst agreed on. A unit of the Reichssicherheitsdienst or the
Geheime Feldpolizei was called by radio or courier to be in readiness on the spot. They took over the actual arrest and house search.
Example two The aerial of the agents transmitter radiated in the direction of a telephone or power line with pylons. The very close-range DF creates bearings either along the wires or towards the metal pylons.
Signals platoon The signals platoon of the company was weak in terms of personnel numbers. It constructed the communications net inside the company, connected the telephone lines into
Telephone exchange, as well as the nearest Forward Control Station or Outstation of OKW/WNV/FU. It was the task of the platoon to main communications between the intercept teams and close-range DF platoons using HF radio links and indirect
teleprinter links. • to forward deciphered messages to the appropriate civilian or military unit to enable the effect of identifying and removing the treachery. The intercept stations of the HF unit working in Italy were established in
Ladispoli and on
Mount Pellegrino. The 616 Intercept Coy, later called the 2nd Company, 1st Signals Monitoring Battalion, had its intercept stations in Fuhrberg and in
Giessen and
Brussels. The station in Brussels was moved to
Bois-le-Roi, Eure.
Monitoring stations The division of duties in an intercept or monitoring station was as follows: Some intercept teams had the mission of clarifying suspicious traffic which had not yet been spotted through radio intelligence channels. Another group had orders to intercept and process traffic which the
unknown traffic branch of the Analysis Sections of WNV/FU III, considered suspicious. This meant that the DF command net was in use at the time. The operator would then pass the frequency of the intercepted signal, call sign and any identifying characteristics of the signal over a party line to which all long-range DF teams were connected. If the traffic to be found was being received in sufficient strength the operator would transfer it to the party line. When the operator checked with the DF unit and established the fact that those who could DF the traffic had done so, the operator ended by giving over to the wire the exact time and serial number of that particular DF assignment. This process as described above could only be interrupted by so-called
Blitzkommando. Blitzkommando mean that the DF command net was needed for the carrying out of a close-range DF operation.
Close-range DF platoons for HF Organisation Close-range HF DF platoons consisted of three to six close-range DF teams with one intercept team. The intercept team had to watch on the frequency which was used for regular traffic by the transmitter to be eliminated. The purpose of this watch was to notify the close-range DF teams the moment the agent began his radio traffic, even it is came up at some time contrary to the regular schedule. If the technician could deduce from the type of traffic emanating from the control station, that the agent was transmitting, then he went on a search action. To ensure the control station as well as the agent being DFd by the close-range section in the field, a second radio officer was given the
Peilkommando frequency to watch. The
Peilkommando was a transmitter that operated on a high output level and transmitted from the outstation, passing a running commentary on call signs, frequencies and messages sent by the agent transmitter being searched for.
Fieseler Storch operations Operations with the
Fieseler Storch were carried out successfully in the Balkans and in Norway. They were used in terrain where close-range DF vans could not, or where partisans were located. The Fieseler Storch would fly around the position to locate it, not over it.
Camouflage and concealment In each case there would be a group of people working for the agent and watching for suspicious people and vehicles in the neighbourhood of the agent's transmitter. The underground organisation would receive constant information about the appearance and behaviour of close-range DF vans as well as belt and suitcase DF teams.
Analysis and evaluation The analysis section was similar to the OKW/WNV/FU analysis section. The analysis section undertook the preliminary work for the OKW/WNV/FU analysis section. At regular intervals, a report of activity was created to send to senior staff headquarters. New clandestine signals of a specific type, were if possible covered by general search until they were either identified by the evaluation section, or they were allotted as new commitments for search. As a general rule, it was the control station of new links that were intercepted first on general search and it was then the work of the operator to intercept and locate the answering signal. As a rough average, it took about two weeks between first interception of a new clandestine signal to intercepting the traffic of the answering station. Within the operational units themselves commitments were allocated to individual operators and a rapid pre-discrimination of logs was carried out to extract information requiring immediate action at the station. Normally, the logs were then passed to the relevant Aussenstelle or Funkmessstelle where more thorough analysis was carried out. The Aussenstellen generally carried the main responsibility for discrimination and allocation of all transmissions taking place within their areas, though very complete details of all the results of evaluation including essential details of every item recorded was passed by the Aussenstellen to the central Auswertung at FU III. This normally took the form of a daily report sent by
teleprinter or
telegram covering the latest activity of regular commitments, new transmissions discovered and believed to be connected with local commitments and general search. A written report covering all activity was rendered monthly by each Aussenstellen. The central Auswertung kept a central index of all transmissions and undertook the more difficult semi-cryptographic work of cracking call signs systems and coded procedures. It was also responsible for the analysis of all general search reports and for the overall allocation of commitments to different units. A special subsection handled all DF results and carried out central allocation of DF network tasks. This system invariably led to a fair amount of duplication since detailed records were kept at HQ, at Aussenstellen and in the evaluation sections of the intercept units themselves. In view of the wide extent and varying local conditions of the German organisation, it is not possible to say that a more rigidly centralised system would have been more effective. The amount of evaluation undertaken at each level varied considerably in accordance with local circumstanced and particularly with the existence of rapid and reliable communication between the Aussenstellen and the operational units. Thus, the station at Bucharest of No. 612 Company carried out most evaluation on the spot, passing its results and receiving its commitments direct to and from FU III; telegrams and reports passing between the two were repeated for information to the HQ of the company at
Cranz, but the latter played a small part in controlling the work of its subordinate unit. In other cases, in order to avoid delay to both the Aussenstelle and the central Auswertung. In 1944, the units in Italy sent all evaluation signals simultaneously to FU III in
Jüterbog, to Funkuberwachungsabt II (Radio Monitoring Department) in
Vienna and to
Luftwaffe No. 1 Special Intercept Company in
Belgrade. • The MBM net. All links between the UK and
Czechoslovakia. • The PS net. All links between the UK and
Poland. • The ZZZ net. All links between the UK and the
Iberian Peninsula. • The south eastern or Balkan net. All links were controlled from the
Middle East. • The
Algiers net. All links were controlled from Algiers. • The eastern or WNA net. All links working to controls in the
Soviet Union The three-letter groups by which the majority of the nets were generally known were usually the call signs of the first links identified in each. A card index was maintained, usually both locally and at the centre, of which activity, schedule and procedural characteristics of each line was recorded. was the transmission of controlled information over a captured agent's radio so that the agent's parent service had no knowledge that the agent had turned, i.e. decided to work for the enemy. The Funkabwehr played an important role in the running of WT double-crosses. In some cases, more or less complete supervision of the case rested with the appropriate Funkabwehr unit, in others it was simply called in an advisory capacity with regard to technical aspects of the case. In all cases, the Funkabwehr had to be informed of the initiation of a playback, whether this was being run by the Sipo or by the Abwehr, and it had to be furnished with full particulars of WT schedules. In more cases, these would already be in its possession since one of its officers was usually called in after the arrest of a WT agent to carry out a technical interrogation. In at least one instance, however, the provision of full particulars did not prevent the Funkabwehr from locating and arresting an agent who was being run by the Abwehr III as an unconscious double-cross. the Orpo unit was entirely responsible for transmission and enciphering although there were no cryptanalysts available.
Plaintext messages were received from the
Sonderführer Huntemann of Abwehr III but the actual working of the agents concerned was handled by the Orpo. This case, in fact, appeared to be one where cooperation between the Orpo intercept unit and the local Abwehr III unit was outstandingly successful. A very similar use was made of the WNV/FU III units in France by Abwehr III in running their double-crosses, the actual extent of supervision by the Funkabwehr varied considerably from case to case. Some difficulties arose here after February 1944, owing to an order by the WNV/FU III HQ that double agents who were not actually under arrest were not to be accepted for double-cross purposes by its subordinate units. In most cases the Sipo placed less reliance than did the Abwehr on assistance from Funkabwehr units. The playbacks run by
Sonderkommando Rote Kapelle, of the Amt IV of the Reich Security Main Office, i.e. The Gestapo, were always carried out in close conjunction with the Funkabwehr, particularly from a cryptographic angle, but the whole of the
Rote Kapelle case was exceptional in that all the C.E. authorities were concerned up to the highest level. Only in the Orpo DF network were the stations linked by line to a central control so that signals intercepted in the home B-Stellen could be put in line and simultaneous bearings obtained on the same signal. A similar system existed on a smaller scale in Norway, with the Oslo intercept stations at
Fornebu and
Jessheim. The signals thus transmitted to the DF stations were passed through loud speakers and the split headphone system was no employed. Where line communication between intercept and DF stations was impractical, the Orpo companies installed WT links. Fornebu station had links to all other stations which worked for the Orpo Company in Norway, and the intercept station in
Minsk had links to its own DF stations. In the latter case the WT operators worked actually in the set room so that at least some direct contact was possible between the intercept and DF operators. The OKW DF service was less well equipped with communications and except whereas at
Treviso they happened to be located at the same site there was no direct contact between the intercept and DF stations. As an exception to this, the DF station at Loutsa had a direct telephone line to the set room at Ecali. In all other cases the DF stations had to work on their own, receiving with their assignments sufficient data to enable them to pick up the required station without assistance from the intercept operators. DF assignments were sent out by WNV/FU III through the appropriate Aussenstellen or intercept company headquarters which usually had as a standing task, the provision of bearings on their own local commitments. Bearings were returned from the DF stations by the same route. This procedure made it impossible to ensure simultaneous bearings and also rendered the issuing of assignments a rather complicated process. At the same time it was possible to use only the DF stations in certain areas if this was sufficient. The Aussenstellen and intercept companies issued their own assignments to the DF stations under their control though these had a lower priority than requirements coming from Berlin; such assignments mostly consisted of items found locally on general search and believed to be connected with the commitments covered by the station concerned. The use of DF stations belonging to other services was a feature of all parts of the Funkabwehr. Assignments for these were passed by FU III through the appropriate signal authorities, but in local areas such as Norway and Greece arrangements were usually made between the commanders on the spot to ensure the greatest possible cooperation and efficiency and in such cases requests to the other services were usually issued by the Aussenstellen direct to the stations concerned. Plotting was carried out centrally in Berlin. The Orpo Funkmessleitstelle had its own DF control and plotting office which issued assignments to the Orpo units and plotting office which issued assignments to the Orpo units and plotted their results, but this worked in reasonably close conjunction with WNV/FU III plotting office, which was able to allot tasks to the other organisation. Funkmessstelle Ost, since it was dealing with material of local military importance passed their bearings to
KONA 6 from whom they also received their DF assignments. In outlying areas, both the OKW and the Orpo units plotted their own bearings and in appropriate cases made use of them to initiate mobile unit action. It is not believed that the statistical methods of plotting were introduced. In cooperation with the local Abwehr III stations, Aussenstellen sometimes also arranged for the playing back of captured agents simply in order to be able to DF the control stations. ==Operations==