Wireless of the Week - week 29

[Bruce Parker (RIP)]

This week is about as wireless as it gets. Flags have been used for millennia for signals and, with the development of patterns and Morse code to indicate letters and numbers, flag signalling evolved to a point where entire messages could be transmitted. Originally used with mechanical arms between fixed stations in the late 1700’s, and rendered obsolete with electric telegraphs by the mid 19th century, the army continued its use because as long as there was a signaler to send and another to receive, it was an economical and practical line of sight communications system requiring no specialized equipment or batteries. Its range was only limited by the strength of the receiver’s telescope, however its limitations were that it could be intercepted by an observant enemy and standing in a conspicuous place waving flags about on a battlefield could often prove fatal.

Army signalling flags were so prevalent in the early 20th century that when the Canadian Signal Corps was formed they were emblazoned on the uniform collar insignia. Regulation flag sizes were 3 ft. square with a 5 ft. 6 in. pole, or 2 ft. square with a 3 ft. 6 in. pole. Both sizes came in white with a horizontal blue stripe or dark blue (later with a white stripe) and used to provide contrast depending on whether you were signalling against a light or dark background.

There were two methods of signalling. First, semaphore signalling required two flags. There were eight 8 positions around the signaler’s body and each letter had a unique position. Numbers used the same positions and whether a flag position was a letter or a number was determined by a unique alpha or numeric sign before the subsequent letters or numbers were sent. The second method of flag signalling required only one flag. The signaler was ‘ready’ with the flag held over his left shoulder. A morse ‘dot’ was sent by waving the flag 45 degrees over his right shoulder for the length of a dot and then returned to his left. A ‘dash’ was accomplished by waving the flag horizontally to the signaler’s right for the longer length of a dash and again returned to the ready. This method had a potentially longer range than traditional semaphore letters as the single flag and only two positions was more easily distinguished at a distance, however it took significantly longer to ‘wave’ out a message.

As in all morse signalling, combinations of letters understood by both the sender and receiver were used to replace long phrases that were regularly used in messages. For instance “CQ” is an abbreviation for “All Stations” and “NN” is “Nothing more coming” at the end of a message.

The signal flags shown here are Canadian produced most likely during the First World War. The signalling pam dates from 1915 before the army produced all of its own. As a civilian product, its first and last pages have advertising for things a soldier might need...shaving cream, boot polish and saddle soap.