Here, for my amateur radio friends, is the full CW (Morse Code) message that is embedded in the promo video.
For my non-amateur radio friends, I cannot claim to have keyed this by hand. My CW skills are rudimentary at best. The clip is machine generated, I’m afraid. If you’d like to try decoding it and you are using a Mac (like me) try ‘Morse Decoder’ from the App Store. There will be similar apps for iPad, iPhones and other devices. Just play the clip while you have one running.
(if I’ve piqued your curiosity in Morse Code or amateur radio or both, check out www.mkars.org.uk)
The relevance of this to ‘The Shelter’ (if you are wondering) is that Martha Watts and Elsie Sidthorpe were both log readers, initially at Beaumanor in Leicestershire and then at Bletchley Park. The job of the log readers was to analyse radio communications received by the intercept operators, in an attempt to identify the patterns and networks used by the German forces in the field. German communications consisted of both ‘chat’ (in plain German) and the more important ciphered messages (for which the German’s used their Enigma machines). These messages were sent in Morse Code and would have sounded much like the message in the clip – albeit that on the air, there would have been a lot more background noise (static and interference), sometimes making accurate reception and logging very difficult work. The intercept operators recorded (in text) the received messages on log sheets which were passed to the log readers for analysis. There will be a much more detailed description of the work of the log readers in the post script to ‘Building 41’ (Book 3 in the series).