iii. Hut 8 and Short Signals.
Hut 8 had not only the responsibility of finding and using Short Signal cribs where required, but also of attempting to reconstruct such code books and indicator tables as had not fallen into our hands. A small subsection was specially responsible for all work on Short Signals.
2. TYPES OF SHORT SIGNAL.
i. Long E-Bars (Alfa-Funksignale).
This category of signal was devised to enable main surface units and U-Boats to send a wide variety of messages quickly when in action. Signals were prefixed Alfa Alfa (E'E') followed by a 3 figure number, Time of Origin and 5-30 four letter groups. The 3 figure number was the indicator, the equivalent settings for which were given the SIGNALSCHLUESSEL FUER DEN FUNKSIGNALDIENST (AUSGABE OKTOBER 1939) (I) which contained the indicator tables and a calendar showing which one of these should be used. The uncyphered version of the message was made of phrases taken from the SIGNALBUCH (C), a general phrase book which was also used for low grade (e.g. visual) signals.
The type of language used can be most easily seen from an example of a long E’ from an U-Boat;
E’E’ 620 9/12/1940 UEYS TWOB........etc.
Message setting MLL (from Table 10).
|Decode;||Gustav Gelb,||Meaning;||Enemy convoy in sight.|
|Anton Caesar8184||Grid square AC 8184|
|Pi 634||U 134|
The long E’ system was used extensively in 1940 and 1941: after that it fell into disuse with the increasing popularity of B-Bars (and Short E’s) which were designed for sending a more limited range of messages in a few letters.
A copy of the Signalbuch was in our hands from early 1941 onwards. The indicator tables also were captured in the first Lofoten pinch and were never changed -- possibly because of the decreasing amount of traffic carried by long E's. It is an interesting feature of these indicator tables that, though 15 x 1000 equivalents are listed, all trigram settings are