page_title: German Radio Intelligence Operations during World War II
section_title: Conclusions
hierarchical_section_title: German Radio Intelligence Operations during World War II / Intercept operations during World War II / Campaign in the West 1940 / Conclusions
caption_attribution_description: English: Situation on June 4, 1940 and actions since May 21
context_page_description: German Radio Intelligence Operation were signals intelligence operations that were undertaken by German Axis forces in Europe during World War II. In keeping with German signals practice since 1942, the term communication intelligence had been used when intercept units were assigned to observe both enemy radio and wire communication. When the observation of only enemy radio communication was undertaken, the term was radio intelligence. The term intercept service was also used up until 1942.
context_section_description: An evaluation of the radio traffic during the first phase of the campaign in the west, with the exception of Dutch traffic, which practically disappeared after five days of fighting, led to the following conclusions:
  The different operating techniques made it easy to distinguish rapidly between French, British and Belgian units.
  Generally speaking, the Allies transmitted too many messages and thus enabled Germany to intercept them without any trouble. However, except for serious violations of radio security, such as the sending of messages in the clear, i.e. Plaintext, the General der Nachrichtenaufklärung and other German intelligence agencies were confronted with considerable difficulties, because the majority of the cryptographic systems used by the Allies proved unbreakable.
  In view of the rapid conduct of operations, particularly those of motorized and armoured units, the information obtained by German radio intelligence was of secondary importance in comparison with that gathered by ground and air combat reconnaissance.
  On the evening of the first day of the attack German radio intelligence picked up messages from the area west of Namur facing Army Group A. The characteristics of these messages left no doubt about the presence of at least two French armoured divisions. The fact that this was reported in time, together with reliable information about the disposition of French forces on the western bank of the  River Meuse, made it possible to warn the German armoured units which had been moved forward to the Meuse and which after crossing the river on 15 May, were actually engaged in heavy fighting.
  Remarkable radio discipline was observed by the French Ninth Army, which was soon attacked by (German: Panzergruppe) Panzer Group Kleist and by the inner flanks of Army Groups A and Army Groups B between Maubeuge (where 90 percent of the town centre was destroyed by bombardments in May 1940) Montmédy.  The information obtained from the 56th Intercept Company, which was committed along the axis of advance of Panzer Group Kleist, was therefore initially unimportant. Since the 56th could not, in the long run, keep pace with Panzer Group Kleist, while carrying on its direction-finding operations, it was ordered to halt on 20 May near Le Cateau-Cambrésis, where it took bearings from two base lines: from the first, directed westward towards Maubeuge-Péronne-en-Mélantois, searching the area bounded by the Franco-Belgian border on the right and by the Somme as far as the Channel coast on the left, while from the base line directed southward through Arras and Rethel it covered the Somme and Aisne sectors.
  The 3rd Intercept Company was assigned to the Laon-Arlon base line after it has crossed the Franco-Belgian border on 14 May. While France moved up division after division in order to cover the open flank, which had developed along the Aisne and Somme as a result of the advance by Panzer Group Kleist, these two intercept companies gradually succeeded in identifying the enemy groupings to the south.
  As early as 14 May, a new army net with three secondary stations was detected. An army HQ was plotted as being west of Verdun, but on the basis of the first observations it could not be identified as that of the French Second Army. One corps was found east of Reims, close to Grandpré. There was some doubt concerning the significance of the staff detected east of Reims; instead of corps traffic it might also have been the inter-net traffic of the army. In the final evaluation the results were treated cautiously, and it was merely concluded that the French second Army sector has been widened, leaving open the possibility that a new front was being built up between Rethel and Stenay.
  Two days later, on 16 May, a new HQ near Épernay appeared on the air with links to the corps in the Challerange-Grandpré area in the centre of the above-mentioned net. On the basis of a plaintext message this HQ was identified as the new French  Sixth Army, commanded by General Robert-Auguste Touchon, who was mentioned by name. This information, at first doub
caption: Situation from 21 May – 4 June 1940
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