As signallers we also trained to use semaphore, but like flag signalling it was never used. Occasionally it helped to communicate instructions between signallers.

Semaphore has an interesting history. Designed by the Chappe brothers in France during the late 18th century, it was reputed to have been used to carry messages between units of Napoleon's army.

The signaller holds the flags arms extended in various positions to signal different letters and figures. The signal letter 'J' also indicates 'alphabetical letters follow'. There are special flag positions to indicate 'numerical signals follow' and an 'erase' signal.

Illustration courtesy The  Royal Australian Navy Communications Branch  Association

There were two forms of visual signalling. In addition to sending morse by signalling lamp we also could use the heliograph. We had four 'Lamps Signalling Daylight Short Range' in the equipment of an Infantry Battalion Signals Platoon, and we were trained to use them. A clear line of sight is necessary between sender and receiver and by day the lamp signals could be read at a distance of about two miles; but by night, six miles. These ranges of operation increased two-fold when signals were read by telescope and we had a number of these in our Signals Stores. Weather, however, was a factor that could affect distances at which signals could be read.

Signallers of the 10th Battalion The Manchester Regiment using the Lamp Signalling Daylight Short Range during training at Redcar in 1937. The signaller on the left is Wilf Shaw who later served with the 6th Battalion The Green Howards in the North African campaign (Tobruk, El Alamein, Mareth Line, Wadi Akarit), invasion of Sicily and the Normandy campaign.

Courtesy Wilf Shaw

It had a ground spike but the lamp was generally used on a tripod. Equipped with morse key and powered by eight 1·5v batteries, the lamp itself had a glass front, fitted with a 10v bulb seated on a spring with a glass reflector at the rear. The lamp had a sighting tube with a small aperture at one end and crossed slots at the other which we used for alignment purposes. Three coloured disks were available to be used according to conditions; amber when fog, green for snow conditions, red to either distinguish the identity of your station or to make your signals distinctive during artillery bombardment. A perforated screen could be used to cut down the spread of the beam during darkness.
Each signalling lamp required testing for true alignment. This was done by aligning the lamp beam about 20 feet away from a flat surface and where the light beam hit the surface it was marked by an 'X' 2¼ inches from the centre of the beam. Looking through the sighting tube, the 'X' should be seen in the centre of the cross slots. If it was not, the amount of the deviation had to be recorded on a diagram inside the lid of the box so the degree of error could be allowed when aligning the lamp for signalling to the distant station. The operator had to look through the circular aperture and move the lamp until the distant station was in the centre of the cross slots or move the lamp taking account of its alignment problems.




The Signals Platoon had four 'Heliographs 5-inch Mark V' as part of our signalling repertoire. A British invention, it was used by the Army in the Far East and our Signals Sergeant told us the heliograph was used to 'flash' the football results around the various Army units on a Saturday night in the years between the Wars. It can be used over long distances; up to 120 miles in the Far East, but about 40 to 50 miles in this country. I recall the special excitement of using the heliograph during a training session on the golf links overlooking the Firth of Forth in the early 1940s, when with the aid of a bright moon the heliograph worked well and the signals could be read clearly.

The heliograph has a signalling mirror with an unsilvered spot in its centre and a siting arm with a jointed sighing rod with movable vanes. It also has a duplex mirror held in 'U' arms with a butterfly screw. The base is equipped with a morse key.

To be able to transmitted signals,the signalling mirror has to be positioned to reflect the light from the signalling mirror on to the distant station.

Although it is not possible to see if the reflected light is precisely on the distant station, there is a sighting mark on a vane which can align the centre of the signalling mirror on to the distant station. This is achieved

when an unsilvered spot in the centre of the signalling mirror causes a small shadow-spot to be thrown on to the vane enabling the signaller to accurately site on to the distant station. The first rough sketch (left) from my signal notes of 1940 indicate the two positions of the signalling mirror: when perdendicular it is reflecting signals to the distant station; when the key is released the suns rays are deflected away from the station.
(1) Shows when the angle between the sun and the heliograph and distant station is at right angles or less, by means of the sighting rod the angle of the mirror can be adjusted to face the bi-section of the angle between the sun and the distant station.
(2) As the sun appears to move across the sky, their is a screw which gives you lateral change whilst you can move the collar to change the elevation.
(3) If over 90 degrees the duplex mirror has to be used. The signalling mirror is faced into the sun's rays which are reflected on to the duplex mirror and onwards to the distant station.

When searching for a distant station, the heliograph has to send a series of dashes which are slowly traversed over an area, doing this by turning the elevation collar or the tangent screw. When the distant station locates your flashing signals, it will align on to you.

Heliograph and Signalling Lamp have never been regarded as a secure means of sending messages as the heliograph beam had a wide lateral dispersion of 16 yards at a mile and the Signal Lamp 40 yards at the same distance and permits interception of the signals. In addition, there was always the danger that light beams would attracted enemy fire.


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