WW1 Early Signalling

World War I, Early signalling and Expeditionary Air Force

WW1 SIGNALLING Nieuport biplane flies over British trenches

Reliable communication was a major difficulty for an attacking force in a World War I trench battle. Wireless communications were in their infancy, so the available methods were telephone, signal lamps, semaphore and homing pigeons, so getting news back to HQ was constantly difficult. The outcome of many trench battles was decided by the company and platoon commanders in the thick of the fighting.




Early communications during World War I , 1914-1918

WWI Communications Trench
WWI Signals Instruments and Equipment

Visual signalling from trenches was dangerous as the operator had to show himself, but it did have important communications roles, particularly where the Army was moving too quickly to establish a telephone network. The first recorded use of the heliograph was in 405 BC, when the Ancient Greeks used polished shields to signal in battle. World War I heliograph used a mirror to reflect sunlight, sending Morse Code as f ashes of light giving instantaneous optical communication over 50 miles. Signalling discs were introduced in 1915 that could be operated under cover and read using a periscope.

 

Semaphore

Semaphore Signal Flags

Dating back to the Ancient Greeks and the use of signal towers, phryctoria. Semaphore uses two flags and sends messages by holding the arms or two flags or poles in certain positions according to an alphabetic code: with a maximum speed of five or six words per minute. It is very portable, so setting up a station is quick, but semaphore is not practical over long distances, at night or through dust and smoke.

Signal Lamps

WW1 SIGNALLING Battle of Arras – Visual Signals, 1917

Signal lamps or Aldis lamps produced a pulse of light using shutters to send Morse Code. They were most useful at night, but also provided handy, secure communications during periods of radio silence and were particularly useful for convoys operating during the Battle of the Atlantic. The disadvantages were lack of visibility in bright moonlight, the rain or fog.

Carrier Pigeon

WWI, Type B Bus, Pigeon Loft
WWI Aircraft pigeon communications

 

The first use of carrier pigeons on the battlefield dates to the 6th Century BC, when Cyrus, the King of Persia, used them to send messages across his empire. In 1914, they were still an effective way of sending messages. Pigeons were the best choice of bird for the job, as they could travel massive distances and still return home. They were also extremely fast, able to travel at up to 60 miles per hour. The birds were also somewhat disposable. Enemy combatants could thwart a message delivery by shooting down the pigeons while they were in the air. To combat this issue, armies sent several pigeons carrying the same message to make sure it got to the intended party. At times there were over 20,000 pigeons and 370 pigeoneers in the war zone. Often pigeons were the sole workable means of communication.

Telephony

RAF desk top training, circa 1920
WW1 Field Telephone

At the start of the war, normal telephones were used, but they were not designed to operate in damp, muddy, noisy conditions. The standard Army field telephone was developed with a buzzer unit and a Morse key so it could be used for Morse Code if the circuit was too noisy for voice transmissions.

Early Radios and Wireless Communications

WWI RFC Ground crew adjusting a camera prior to a photo recconnaissance flight
WWI Chrystal Receiver
RFC Wireless operator attached to Royal Artillery providing a ground to air Morse link, c1917
WWI-Wireless Crystal Receiver

Wireless communications and early ground-to-air signalling Radio communication came to play a vital role for all combatants during the war. An early type was the spark transmitter that had two conducting electrodes separated by a gap. When a sufficiently high voltage was applied, a spark bridged the gap forming a mark or dot, ideal for Morse Code transmissions. The aerial spark transmitter was a major advancement. Although it weighed 100 lbs, it was considered very compact and simple. The metal frame of the aircraft formed the antennae, while a long trailing wire provided the ‘earth.’ This automatically pulled loose if it became entangled and was replaced. The ground receiver was portable and known as a ‘knapsack’ station. Wireless-equipped planes would fl y over the enemy’s lines and the operator would telegraph the condition or manoeuvres of the enemy to the ‘knapsack’ station, or direct the gunfire of artillery batteries on the ground by signalling to an Royal Flying Corps wireless operator attached to each battery. Most flights were within two or three miles from base, although 50 miles was theoretically possible. The main drawback of wireless was that it could be monitored over a wide spectrum. Army commands were worried about being directionally found and were reluctant to use the new technology, so tuned coiled receivers or crystal sets were introduced to reduce this problem. The British began to use short-wave radio tuners in the trenches. By 1917 they had began to equip aircraft with air-to-air continuous wave voice radio and by the end of the war, the RAF had put radios onto 600 planes, and had 1,000 ground stations and 18,000 wireless operators.

Wireless communications and early ground-to-air signalling Radio communication came to play a vital role for all combatants during the war. An early type was the spark transmitter that had two conducting electrodes separated by a gap. When a sufficiently high voltage was applied, a spark bridged the gap forming a mark or dot, ideal for Morse Code transmissions. The aerial spark transmitter was a major advancement. Although it weighed 100 lbs, it was considered very compact and simple. The metal frame of the aircraft formed the antennae, while a long trailing wire provided the ‘earth.’ This automatically pulled loose if it became entangled and was replaced. The ground receiver was portable and known as a ‘knapsack’ station. Wireless-equipped planes would fl y over the enemy’s lines and the operator would telegraph the condition or manoeuvres of the enemy to the ‘knapsack’ station, or direct the gunfire of artillery batteries on the ground by signalling to an Royal Flying Corps wireless operator attached to each battery. Most flights were within two or three miles from base, although 50 miles was theoretically possible. The main drawback of wireless was that it could be monitored over a wide spectrum. Army commands were worried about being directionally found and were reluctant to use the new technology, so tuned coiled receivers or crystal sets were introduced to reduce this problem. The British began to use short-wave radio tuners in the trenches. By 1917 they had began to equip aircraft with air-to-air continuous wave voice radio and by the end of the war, the RAF had put radios onto 600 planes, and had 1,000 ground stations and 18,000 wireless operators.

At the start of the war, normal telephones were used, but they were not designed to operate in damp, muddy, noisy conditions. The standard Army field telephone was developed with a buzzer unit and a Morse key so it could be used for Morse Code if the circuit was too noisy for voice transmissions.

WWI Wireless Trailer 1919
WW1, Cessation of Hostilities Message

Morse Code

1914 Morse Code Disk
WWI Wireless Transmitter/Receiver Case
British Evacuation and RAF Victoria Aircraft at Sherpur aerodrome, 1928

Created for Samuel Morse’s electric telegraph in the early 1840s, it was also widely used for early radio communication from the 1890s. For the first half of the twentieth century, most of the high-speed international communication was conducted in Morse Code, using telegraph lines, undersea cables, and radio circuits. Captain, later Vice Admiral, Philip Colomb had the idea of flashing the dots and dashes using a lantern in 1867. His original Naval code was replaced by Morse Code with the addition of several special signals.
Between the Wars Tactical communications and airfield activation can trace its roots back to the beginnings of expeditionary air wings in World War I. The Royal Flying Corps took over the Air Battalion of the Royal Engineers and Naval aviation. They comprised one airship, a man-carrying kite squadron plus two aeroplane squadrons and from their first documented campaigns, maintained the need for enablers and engineers to support deployed aircraft squadrons and facilities. In 1928, the fledgling RAF was used in the evacuation of Kabul and airlifted almost 600 people. They depended on dedicated teams to activate airheads and facilitate ‘reach back’ communications.

Royal Flying Corps, Eyes of the Army, 1914-1918

RAF Wireless Operator Badge

WWI Wireless Operator badge, Metal