[Observer1940]

Hello Andy

My research to date is for Bomber Command in 1940, who mainly used W/T Wireless Telegraphy and some voice communication, but it may offer a few suggestions if searching in the TNA.

I noted a complaint from Bomber Command to say that they could not divert bombers to a Fighter Station as most Fighter Aerodromes had no trained W/T operator on duty and Fighters used R/T.

Bomber Command Crews used 4 main sources in the Summer of 1940 (two were code and the other a German Beacon Intelligence forecast).

Regarding Bomber Command aircraft Call-signs, these only occasionly appear sometimes on SOS Forms and occasionly in a full Court of Inquiry when a Controller was communicating with the aircraft and a Witness at the Inquiry. Only the separate MSI (Movement Serial Indicator) appears in Bomber Command documents.

But I have also noted references to CD.75(2) sometimes expressed C.D. 75(2).
C.D. = Confidential Document and (2) in brackets was likely part 2 according to other docs seen.

Whether all parts of C.D.75 were peculiar to W/T Signalling only is unclear and although I have never really searched for C.D. 75 (in the original dept reference), some C.D. & S.D. docs appear in AIR 10 and elsewhere.

I presume you have seen the following in TNA, but it may be a general WW2 history only? It was all Fighter related and too thick to go through page by page and no notes were made.

AIR 20/12426 RAF signals: volume V; fighter control and interception 1939-1945 original dept ref "CD 1116"

There is an actual manual/file for Bomber Command at AIR 14/1586, but W/T related.

This R/T information must be about somewhere, although a lot of 1940 signalling information is not in TNA.

I don't know how authentic the Battle of Britain film was, that is for you Battle of Britain specialists, but would the film researcher have received such information/correspondence at the time (who then decided to do their own thing), but the correspondence survives either in a film archive, or university Library Collection, who sometimes acquired the older archives of film and publishing companies, or when they went out of business?

I have been quite surprised at the technical manuals and wealth of official aviation publications at the RAF Museum Archive, when enquiring.

Mark