The experiences gained pointed to the absolute necessity of allotting sufficient personnel to battalions for purposes of signalling and telephonic communication.
The result of these experiences was that in May the first Tank Signal Company was formed, the personnel being provided from those already trained in the tank battalions, to which a few trained Signal Service men were added. The formation of this company was shortly followed by that of the 2nd and 3rd Companies, the 2nd Company taking part in the battle of Messines.
In May the first experiments in using wireless signalling from and to tanks were carried out at the Central Workshops at Erin, various types of aerials being tested. In July a wireless-signal officer was appointed to the Tank Corps and he at once set to work to get ready six tanks fitted with wireless apparatus for the impending Ypres operations.
These signal tanks, when completed, were allotted to the Brigade Signal Companies, and in isolated cases, during the battle, came into operation, but in the main they did not prove a great success on account of the extreme difficulty of the ground. Eventually these tanks were placed at different points along the battle front and were used as observation posts by the Royal Flying Corps, wireless being employed to inform the anti-aircraft batteries in rear whenever enemy’s aeroplanes were seen approaching our lines. Many wireless messages were sent and much experience was gained by means of this work.
By the end of September, on account of signalling equipment being obtained, it was possible to carry out training on much better lines than heretofore. This was fortunate, for it enabled intensive signalling training to be carried out prior to the battle of Cambrai. During this battle a much more complete system of signals was attempted, and wireless signalling proved invaluable in keeping in touch with rear headquarters and also in sending orders forward. On the first day of this battle a successful experiment in laying telegraph cable from a tank was carried out, five tons of cable being towed forward by means of sledges, the tank carrying 120 poles, exchanges, telephones, and sundry apparatus from our front line to the town of Marcoing.
The signalling experiences gained during the battle of Cambrai proved of great value, the most important being that it became apparent that it was next to useless to attempt to collect information from the front of the battle line. Even if this information could be collected, and it was most difficult to do so, it was so local and ephemeral in importance as to confuse rather than to illuminate those who received it. Collecting points about 600 yards behind the fighting tanks were found to be generally the most suitable places for establishing wireless and visual signalling stations.
At these stations officers were posted to receive messages and to compile them into general reports, which from time to time were transmitted by wireless to the headquarters concerned.
After the battle of Cambrai the 4th Brigade Signal Company was formed. This Company was the first one to have a complete complement of trained Signal Service officers and men allotted to it. It carried out exceptionally good work during the operations in March 1918.
At this time the complete organisation of signals in the Tank Corps may be shown graphically as follows: