Great War Telephone Equipment 1914-1918:

British Field Radio (Great War)

A forward Wireless Station

When defining the principal advances in signal practice during the battles of 1917, prominence was given to the success which attended the use of the power buzzer and amplifier stations and to two fresh developments of army wireless - the initial attempts to use special "forward" sets, and the use of continuous wave wireless with the artillery. Even yet, forward wireless had not gained its rightful place as an essential means of communication, though in many situations the wireless stations had dealt with traffic of vital importance. Month after month, propaganda work had been zealously carried on, and the education of the Signal Service in the use and management of forward wireless sets had been steadily pursued. The decentralisation policy, coming as it did at a critical period in the history of signals, much improved the chances of wireless making good. It occurred too late to have its full effect upon the position battles of this year, but was destined to act as a potent influence for the popularisation of this form of signalling. Its complete effect was seen in 1918 when, at the time of the March German offensive, wireless in the Divisions was at last in a position to utilise to the full every opportunity given to it. Then and only then, was seen the wisdom of the policy persisted in in spite of every obstacle.

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Inside the dug-out.  Wireless Operators at work

30 Watt British Field Radio Set (Receiver)

 

50 Watt British Field Radio Set (Transmitter)

 

130 Watt Wilson Set Long Wave (Transmitter)

 

Meanwhile, in 1917, two principal developments marked the progress of wireless telegraphy. The first was the invention of special "forward" sets to supersede the trench set in work for which the latter was not fitted. The British field wireless set (trench set, spark, 50watts) was eminently fitted for its normal work as a station for work at Brigade headquarters or Divisional headquarters. In stationary warfare, when time and labour were available, it had often been used with good effect in special situations well forward of either. It could not, however, be called a "mobile" set in the strict sense of the word. It required a party of at least three men to carry it forward, and the accumulators used with it were bulky, easily damaged, and required frequent renewal.

The set could not be used with any likelihood of great success as a subsidiary part of the Brigade forward route in a substantial offensive. In addition its aerial was fairly conspicuous and limited its use in exposed positions near an ill-defended front line. A conspicuous wireless set was a special mark for enemy attention and as such was anything but popular with headquarters staff. There was a distinct element of nervousness in their attitude towards it and this was strengthened by the spread of rumours as to the extreme accuracy with which the enemy could locate such a set by means of directional apparatus. Something much less obvious both to the enemy and to our own Staff was required. This need was met by the invention of the "loop" wireless set. (known officially as the  "W/T set, forward, spark, 20 watts, B, front and rear." A full technical description was issued as "Technical Instruction No. 4. November, 1917."

      

(REAR)                                             (FRONT)

WT Forward 20 watt Spark Transmitter      

The essential advantages of the new sets were their lightness and compactness, inconspicuous aerials, and short wavelengths. They were designed to work on one or two low fixed wavelengths (65 and 80 meters) far below those in use by the Royal Flying Corps, the trench sets, or the direction finding sets. They were made in four distinct parts, a front transmitter and receiver and a rear transmitter and receiver. Special canvas "carriers" were issued with the sets and much improved their portability. The front sets were intended for erection well forward- possibly even within direct view of the enemy - and had "ground" aerials for the receiver and a small brass loop fixed to a bayonet for the transmitting aerial. This set could be erected and worked entirely under shelter, except for the projecting ends of the ground aerials which were invisible at a distance of a few yards. The rear set on the other hand, had a low horizontal aerial supported on tripods. This was less inconspicuous, but much more efficient than the forward aerials. The general range of the sets was from 2,000 to 3,000 yards so that they were well adapted for use between main stations along the Brigade forward route and also between battalion forward command posts and the Brigade forward station.

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Waggon mounted rear listening set

Three considerations reduced the practical value of the sets.  The first was a certain "individuality" about the earlier sets which was the cause of a rather disconcerting uncertainty as to their efficiency. The second was an unduly great dependence upon favourable circumstances and surroundings for their success. The third and deciding factor was shortage of supply which prevented the universal training of forward signallers in the use of the sets until the opportunity for their deployment was almost past. Even in 1917, individual signal units-notably those of the Canadian and Australian Corps, often more hospitable to fresh departures in signalling than the Imperial troops- made conspicuous successes with the new sets. On individual occasions they were the only means of signal communication between forward units for as long as 24 hours at a time. For a short time in the summer of 1918 they almost completely ousted the power buzzer and amplifier sets from the position these had won as a result of their brilliant successes in the 1917 battles.  Then, however,  mobile warfare set in  and the loop sets, in company with other innovations of the position warfare period, were relegated to the bottom of the transport wagons and to relative obscurity.

Pack Set type B1	Motorcycle Pack Set	Horse mounted Pack set	Wireless Pack Set

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The trench wireless set itself underwent little change during this year. Slight technical alterations resulted in a more robust and efficient set, but in its essentials it remained unchanged, awaiting its opportunity in the future. For a short time these sets achieved a certain popularity in the artillery who were beginning to turn their attention to wireless for observation purposes.  From this position, however, spark wireless was quickly driven by its half brother, continuous wave wireless, which was just beginning a rapid and extraordinary career as applied to Army purposes.

These advantages were, however, for some time, counter-balanced by equally great disadvantages which could be gradually overcome. The sets were extremely delicate, so delicate in fact that until 1917 none had been evolved which were capable of  surviving the exigeant conditions of service in the field. The work also was technical in the highest degree, for the most simple sets required delicate and careful adjustment. On the early stations, the C.W. operator needed to be considerably more than a good manipulator of the key. There were literally dozens of ways in which sets might go wrong, and some of these faults, at least, he must be capable of diagnosing and repairing.

Marconi 16.  1915  Carborundum crystal receiver designed to be insensitive to vibration

These earlier sets were gradually improved upon, and then C.W. wireless came further and further within the sphere of practical politics, though until the Armistice its use in the forward area was practically confined to the artillery.

The Army Wireless Section

A totally different aspect of Army Signals was cared for by the Army wireless section, and the Army wireless observation group. The former was seldom or never used for the passing of tactical messages. The line system was almost always sufficient to carry the normal message traffic. If a breakdown occurred on one route, there was always a choice of several others available. Nevertheless the Army wireless stations had important duties to fulfil. Of no method of signalling is it so true of wireless that central control of message traffic is essential if efficiency is to be obtained. Every spark wireless station can interfere with every other station in its neighbourhood that is working on the same or a near wave-length. Every station can be overheard by special enemy stations devoting their whole energies to this purpose. These are the two cardinal facts that needed to be borne in mind by the officers responsible for Army wireless. The principal activities of the Army personnel resulted from these two facts. It was their business to keep constant watch on all the waves in use by their Army for two purposes. Stations near the front line who could not attract the attention of the stations to which they were working might need the assistance of the higher-powered Army station to help to establish communication. It might even be necessary for the Army station, having picked up such an unacknowledged message, to switch over to the transmitting side and send it out with a strength sufficient to drown all lesser stations.*

*An excellent example of the value of the Army control station can be cited from the records of the battle of Cambrai in November, 1917. An infantry Brigade completely cut off by the enemy could not get through by wireless either to its Division or its Corps, possibly on account of the latter headquarters being in retreat, possibly because distances were too great. The Army wireless control station heard its call, took the message and promptly forwarded the latter to its rightful destination.

The second duty of the Army wireless station was of yet more general importance. It was its duty to watch for errors in wireless discipline from the signal point of view. Any serious error would soon be brought home by the Intelligence Staff working through the medium of the wireless observation groups, but, if strict discipline was to be observed, a careful watch for indiscretions must be kept by the Signal Service itself. It was the duty of the O.C. Wireless of the Army to suppress all tendency to individuality on the part of wireless operators. Innovations in procedure, little mannerisms on the key, irrelevant remarks between operators, indiscreet messages, all of these things needed to be controlled and eliminated as far as was possible, since they might so much away to a presumably watchful enemy. It was in preventing such occurrences and in tightening up discipline, that the greatest utility of the Army Wireless Section lay, though its other functions were also of importance.

Source: The Signal Service (France) by R.E. Priestly, M.C. , B.A. (Late Major, R.E.) Chatham: W. & J. Mackay & Co., Limited.     1921

C/W Sets

C/W Field Set Mk 111

   

HT unit with 30 Watt Coil for use with   C/W set Mk 111

 

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