The Wireless War in the Air
In 1910 events had occurred that were to have a profound effect on military flying and the use of artillery in World War One when Wireless communication first took to the air.
The world’s first air-to-ground wireless communication from a heavier-than-air aircraft occurred on 27th August 1910. James A.D. McCurdy, a Canadian aviation pioneer, transmitted a Morse code message to Henry M. Horton, while flying over the Sheepshead Bay race track, in Brooklyn, NY.
In England, less than a month later, a pioneer British aviator called Robert Loraine (1876-1935), who was also a highly successful stage and screen actor for over 30 years, performed the same feat. Robert Loraine was also the first aviator to successfully land in North Wales and fly across the Irish sea on September 11th. In August 1910, after being caught in a severe rain storm, he piloted the very first plane to land on the Isle of Wight, touching down on the Downs, just east of the Needles. During 1910, he was also the first person to use the term ‘Joystick’ in aviation, he wrote it in his logbook, and it later became the standard term for an aircraft control column.
On the 27th September 1910, leaving his role in his West End play to an understudy, Loraine was rushed by the Ministry of Defence to Larkhill, to fly a Farman biplane which was made by the British and Colonial Aeroplane Company in Bristol. A portable Marconi wireless transmitter weighing 14 lbs was attached to the passenger seat and aerial wires were stretched along the breadth and length of the bi-plane. The Morse key for tapping out the messages was fixed at the airman's left hand. His task as a member of the ‘opposing army’ in the military exercise procedure was to transmit radio messages from the air near to Stonehenge, by tapping a Morse code key with his left hand, whilst flying the controls with his right. The message simply said 'enemy in sight' and his signals were successfully received in the 'Bristol' hangar.
Five days later Loraine was able to transmit a wireless signal in excess of one mile, leading the Bristol company to consider the use of aircraft for long-range wireless transmission. Present at the manoeuvres were Lord Roberts, Lord Kitchener and Sir John French. Also present, and particularly interested in the aerial activity was a certain Mr. Winston Churchill, the then Home Secretary.
With these early successes the Marconi Company began experimental work on ground to air and air to ground radio communication, but it quickly proved to be a difficult task.
During the first years of the First World War the British Forces had no option but to rely on wireless communication using the crudest of equipment. The first attempts at installing aircraft wireless communication systems consisted of a large and heavy spark set with its batteries mounted in the plane and a massive crystal receiver on the ground.
It was quickly found that in an open cockpit, against the roar of engine, wind and gunfire, it was almost impossible to reliably understand Morse code sent using this equipment or any other. It also seemed to be impossible for the pilot or observer to tune his transmitter and operate a Morse key in an open cockpit, usually strapped to the top of his knee. It became clear that the ability to transmit speech was essential, not only for speed of command, but because the pilot of a single seat plane could not be expected to manoeuvre the aircraft and send Morse code at the same time.
Another problem that beset early installation of wireless in aircraft was where to put the transmitter and battery. Extra items presented a problem for an already cramped cockpit, and the observer had to perch the transmitter on his knee, and keep the battery at his feet. All this equipment also left the observer and pilot virtually defenceless.
The other major handicap facing the introduction of wireless into aircraft was the very limited load capacity of the machines and the sheer weight of the wireless apparatus. The installation of wireless in aircraft now required considerable experimentation, original thought and development. The early sets weighed 75 lb (35 Kg) (some early variants 100 lb) and filled the observer’s cockpit (and sometimes most of the pilot’s), while some 250 feet of aerial wire had to be unwound by hand from a spool mounted on the fuselage alongside the observer’s position.
This in itself created several serious problems. In the event of attack it was impossible to reel the aerial wire in, so it had to be cut away. The increased drag also made the aeroplane very difficult to fly at the best of times, in combat it could become a death-trap. The wire also had a tendency to wrap itself around the aeroplanes control surfaces if its end-weight twisted loose. To cut down on engine interference the ignition cables were screened with metal piping and sheeting, which not only added unwelcome weight, but also tended to make the aeroplanes power unit even more unreliable.
It had not yet been appreciated that signal strength was of less importance than weight. It was believed that a reasonably long range was necessary in order to transmit reconnaissance information. It subsequently became evident that for artillery co-operation the weaker and hence smaller sets, with lighter batteries gave a range consistent with the range of the guns concerned.
The Royal Flying Corps (RFC) was established in May 1912 and Major Herbert Musgrave was placed in charge of RFC's experiments. In 1896 Musgrave had applied and received a royal commission in the Royal Engineers. Three years later, Lt. Musgrave was sent to South Africa, where he remained throughout the Boer War. Musgrave witnessed the first flight across the English Channel made by Louis Bleriot on 25th July 1909 and he immediately saw the military significance of this event. Musgrave was impressed by the sight of the first aircraft to cross the English Channel and immediately and went to the War Office to explain the possible dangers this invention would pose to Britain's security.
Musgrave proposed the formation of a military aviation service to face this new threat from the sky but his ideas were rejected. Sir William Nicholson, British Chief of General Staff 1908-12, later declared that: 'aviation is a useless and expensive fad advocated by a few individuals whose ideas are unworthy of attention.'
Musgrave, continued his campaign for a military aviation service and when it was decided to form the Royal Flying Corps in May 1912, he was seconded from the British Army. At the time, Musgrave was one of only eleven qualified pilots in the RFC.
He was placed in charge of the Royal Flying Corps' experimental projects, including research in ballooning, kiting, photography, meteorology and bomb-dropping. One key area of research was to determine how and if wireless telegraphy could be used by military aircraft.
The creation of a separate Headquarters Wireless Telegraphy Unit (HQ WTU) under his command on 27th September 1914 reflected the importance attached to this work. The growing pressure on wireless was officially recognised by the creation of a dedicated unit No. 9 (Wireless) Squadron, RFC, formed at St. Omer, France, on 8th December 1914, from the HQ WTU. This original unit only lasted for a brief period, its two flights being absorbed into other units early in 1915, and its headquarters disbanded.
Like the British Army, the Royal Flying Corps had still entered the war with a very limited appreciation of the possible roles for wireless communication in wartime. Indeed the use of wireless telegraphy from aircraft to the ground was still widely viewed by the Army as impracticable. Consequently the first RFC units that arrived in France were equipped with only one airborne spark transmitter and one ground based receiver between them. Also, the radios in the aircraft could not receive signals, so the pilots could not be sent any instructions or questions from the ground.
But Musgrave was convinced that wireless had a vital role to play especially for RFC aircraft for spotting and reporting back the fall of artillery fire. The results of the artillery fire were easy enough for the pilot to observe; the problem was communicating any necessary corrections to the firing battery. The early method was for the flier to write a note and drop it to the ground where it could be recovered. The only other system saw a 'forward observer', often supported in a very exposed basket suspended beneath a balloon, who had to make sketches of what he saw over the enemy lines and then the information was dropped over the side and ferried to the British batteries as ranging aids.
No 9 Squadron, under the command of Musgrave devised a system where pilots could use wireless telegraphy to help the artillery hit specific targets. The aircraft observer carried a wireless set and a map and after identifying the position of an enemy target was able to send messages such as A5, B3, etc. to the artillery commander. Musgrave's 'Zone Call procedure'
By 1915 all the western front maps were 'squared' and a target location could be reported from the air using alphanumeric characters transmitted in Morse code. Batteries were allocated a Zone, typically a quarter of a map sheet, and it was the duty of the RFC signallers on the ground beside the battery command post to pick out calls for fire in their battery's Zone. Once ranging started the airman reported the position of the ranging round using the clock code, the battery adjusted their firing data and fired again, and the process was repeated until the pilot observed a target or close round. The battery commander then decided how much to fire at the target.
At first the results were mixed. Observing artillery fire, even from above, requires training and skill. Within artillery units ground observers received mentoring to develop their skill, this was not available to RFC aircrew. There were undoubtedly some very skilled artillery observers in the RFC, but there were many who were not and there was a tendency for 'optimism bias' and reporting rounds on target that weren't. The procedures were also time consuming.
The ground stations were generally attached to heavy artillery units, such as Royal Garrison Artillery Siege Batteries and were manned by RFC wireless operators. These wireless operators had to fend for themselves as their squadrons were situated some distance away and they were not posted to the battery they were co-located with. This led to concerns as to who had responsibility for them and in November 1916 squadron commanders had to be reminded 'that it is their duty to keep in close touch with the operators attached to their command, and to make all necessary arrangements for supplying them with blankets, clothing, pay, etc'.
The wireless operators' work was often carried out under heavy artillery fire in makeshift dug-outs. The artillery batteries were important targets and antennas were a lot less robust than the guns, hence prone to damage requiring immediate repair. As well as taking down and interpreting the numerous signals coming in from the aircraft, the operator had to communicate back to the aircraft by means of cloth strips laid out on the ground or a signalling lamp to give visual confirmation that the signals had been received. Until 1917 the wireless communication was one way as no receiver was mounted in the aircraft and the ground station could not transmit to the pilot.
The Globe on 30th January 1919 told something of the story:
SPARKS' UNDER FIRE
RAF Wireless Operators Had No 'Safe' Jobs
The public was prone during the war to assume that because certain RAF work was of an unobtrusive nature it was, therefore, of a safe nature. All ground jobs in the R.A. F. were commonly believed to be soft billets.
It is possible, however, to give a large number of instances where this belief, based on lack of knowledge, was extremely inaccurate.
Let us take the case of the RAF Wireless Operators and the Officers who supervise them. The public had a vague idea of a comfortable hut so far behind the lines that gunfire was seldom heard, in which the operators enjoyed a comparatively restful time, just taking a few messages when a squadron happened to be in flight. The facts may come as a surprise.
The Wireless Operators were attached to batteries of artillery: sometimes two to a battery, sometimes even only one to a battery. These men lived with the gunners, sharing the same risks and hardships. This work required continual alertness and close attention, and was more often than not performed under heavy fire in a hastily-constructed dugout, rocking with the concussions of exploding shells, which every now and then would extinguish the gutter candle the only illumination for the little shelter.
There would sit the operator, with the receiver on his head, picking up the faint Morse signals amid a pandemonium of noise. Not only had he to pick up the signals, but to distinguish those coming from the particular machine with which he was working from the numerous signals of other stations.
Frequently his mast and aerial were put out of action by shellfire. He must go into the open instantly to repair it. Sometimes this would be necessary three or four times during one shoot. During a push there was often no time to build even the flimsiest shelter. The operator advanced with his battery, rigged up his mast, and took up his position in the nearest shell hole.
In the long days of summer there had to be an operator on duty from about 3am to 10pm As long, in fact, as aeroplanes and guns could co-operate. And with the scarcity of trained personnel which existed at times, many of these operators were on duty from dawn until dusk – relieved perhaps for a few moments during the day by a battery telephonist.
Lives depended on them. Upon the skill and endurance of these men has depended the accurate shooting of the guns and upon that the saving of the lives of thousands of our infantry. There was a yearly average of over 400 casualties among the RAF wireless operators during the four years of the war. The number rose to nearly 500 between May and November, 1918.
This is not a large number in itself, but compared with the number on the establishment, it represents a large percentage indeed, unusually large for a ‘safe’ job.
The men who joined the wireless units were only together for their initial training as they were afterwards transferred to Heavy and Light Artillery Batteries, some to the Cavalry and Infantry others even to the Fleet. The operators trained and fought with these units.
When he arrived the Wireless Operator was essentially on his own amongst a lot of strangers doing a job of work which no one understood, except possibly the Senior Officers. He was a much maligned person as part of his equipment was a thirty foot steel mast and 100 feet of aerial wire which had to be erected on the battery site or wherever else he had to go. The operators had to take the utmost care regarding camouflage but it was still enough to infuriate their fellow soldiers as it gave their position away. One operator recalled: 'Blimey, I was billeted in a broken down pig-sty only about 100 yards from that battery positioned in the cemetery'.
The following is a transcript of the notes made by Monty Pocock No. 9176. MM. RFC, giving his Details of Service during the 1914 - 1918 War as a wireless operator.
'16-5-16. It was my duty to take the mid-night news. It was thundering and lightning flashes were very frequent and it was also raining heavens hardest. Well the signals from Poldhu, which were usually weak, were this night particularly faint, and coupled with the heavy rain falling on the corrugated roof of iron, things were well nigh hopeless. I should imagine I received about a quarter of the news, but when I read what I had taken down, I really had the breeze well up. I did not know whether Lord Kitchener had been drowned, promoted or sacked. All I could pick up clearly was what he had done in the past, and H.M.S. Hampshire which had been sunk. Being exceptionally raw at the time, I awoke the Major of the Squadron (he was a one-armed man) at 2am and explained what I had received. I still blush at the things he called me. However he was decent enough to apologise to me the next morning when the news of Lord Kitcheners death came through. It was from this 21 Squad. that we received wireless instructions regarding the movement of cavalry, and two of us took a Receiver, masts and a special set of ground signals to Montreuil near the coast. The set was installed in a small cottage, and a small room in which we were taking the signals was filled with brass hats of all types, Brigadiers, Colonels and what have you, all jabbering away at once. I have never heard of an instance, before or since, when such a collection of Brass was told not to make such noise by an ordinary 2nd Class Air Mechanic. I had such a dirty look from all and sundry, but at least it had a wonderful effect - there was not a murmur afterwards. I was congratulated afterwards by the Officer in charge for being so forthright.
May/June 1917. The Battery next moved to Kemmel village which soon proved to be a hot shop. Had my mast blown down 3 times in 2 days, and the guys and halyard looked like pieces of string instead of ropes. It was just about this time Lieut. Maddocks visited me, after I had spent 36 hours in a gas mask. Imagine what I felt like telling him when he said I should splice all the ropes and paint different colours around the mast. I was saved having to do all this nonsense by the Major who heard the instructions. He in no uncertain way told the Lieut. where to go, and not come bothering again. This battery position was too hot, so we had to pull the guns back behind Kemmel Hill. There we continued to plaster the German guns just before the mines at Messines and Wytschaete ridges went off. After the battle, the battery then pulled out and made north. We had a few weeks rest at Poperinghe before taking up another position on the Ypres Cominese Canal, just abreast of Bedford House. No. 121 Siege Battery, 9.2' Howitzers. were just below us, and below them at Spoil Bank was another battery in which Alfred H. Lane served as an Operator. We had many excellent shoots from this position, but it got a decidedly hot one. It was here on the 25th June I was awarded the Military Medal.'
Citation for the award of the Military Medal to 1st Air Mechanic Monty Pocock for gallantry on 25th June 1917:
'For conspicuous gallantry and devotion to duty on June 25th 1917, whilst receiving Wireless signals from an aeroplane for a Siege Battery, which was carrying out a shoot with aeroplane observation, his wireless aerial was cut by hostile shell fire. 1st A/M Pocock mended his aerial under heavy fire and continued receiving the signals with only slight interruption to the shoot. On several other occasions he has repaired his apparatus under heavy fire.'
Towards the end of June we were completely wiped out, all of the guns were destroyed and the ammunition blown up. We suffered very heavy casualties, only 28 men left unwounded out of the total complement of the battery. I was wounded the next day and taken to the C.C. Station, after to Hospital at Etaples.'
Two of the most important officers involved in airborne wireless development were Lieutenants Donald Lewis and Baron James who developed both the equipment, spotting and reporting procedures during operational sorties over enemy territory. On 24th September 1914 Lieutenants D.S. Lewis and B.T. James used airborne radio for the first time in warfare. Both were members of No.4 Squadron, Royal Flying Corps and were involved in directing an artillery barrage from the air during the first Battle of the Aisne. Their radio log begins:
4.02 pm A very little short. Fire, Fire.
4.04 pm Fire again. Fire again.
4.12 pm A little short; line OK.
4.15 pm Short. Over, Over and a little left.
4.20 p.m. You were just between two batteries.
Search 200 yards each side of your least shot. Range OK.
4.22 pm You have them.
4.26 pm About 50 yards short and to the right.
4.27 pm Your last shot in the middle of three batteries in action;
search all round within 300 yards of your last shot and you have them.
4.42 pm I am coming home now.
The Artillery Battery and Corps commanders were generous in their praise of the wireless section’s achievements that did much to offset the superiority in artillery enjoyed by the Germans.
‘Today...’ said Commander II Corps in a further telegram to GHQ dated 24th September 1914:
‘I watched for a long time an aeroplane observing for the 6-inch howitzers of 3rd Division. It was at times smothered with hostile anti-aircraft fire but nothing daunted it; it continued for hours to send signals through a wireless installation, to observe the fire – indeed to control the battery – with most satisfactory results. I am not mentioning names, as to do so, where all are daily showing such heroic and efficient work, would be invidious’.
As a result, by the third week in September artillery observation by aeroplanes equipped with wireless equipment had become the rule. Indeed, such was the success of Lt’s James and Lewis that by the end of the Battle, not only had wireless observation proved itself, but also the demand for a dedicated corps of wireless aircraft far exceeded the RFC’s ability to satisfy. In 1914 the wireless section’s resources still comprised just two equipped aircraft (BE2’s numbers 317 and 336).
The young flyers experiments, under conditions of actual warfare, proved that in principle wireless could provide a great improvement over the then existing method of reconnaissance. As the First World War progressed the possible advantages of communicating from the aircraft to the ground became obvious, especially for the immediate observation of the fall of shells and the reporting of troop movements. But the early generation of spark transmitter and crystal sets were simply not good enough to offer a practical solution that could with stand the rigours of operation wartime flying. There was also no practical or reliable aircraft receiver available.
Crystal set Receiver, c. 1917 (MWT)
Crystal Receiver used in aircraft during World War One. Mounting was in a wooden box, with the unit suspended on two rubber bands. Morse code only could be received on this unit.
RFC British wireless transmitter, c. 1915 (MWT)
The Transmitter No 1 was used by the Royal Flying Corps (RFC) on the Western Front for artillery spotting duties. It was first used by the RFC during the battle of Neuve Chapelle in March 1915. It was also used by the British Army in France for artillery cooperation, and in Home Defence for spotting work. Transmitter Type No 1 was a lightweight simple spark gap transmitter assembled into a gas-tight box with its inductance calibrated in wavelengths and inductive coupling provided by a wander plug. The transmitter and Morse key were totally enclosed to prevent the spark igniting petrol vapour in the cockpit. It was usually mounted on a tray on the side of an aircraft's fuselage, and the equipment required a complete overhaul after every flight. The No 1 Transmitter operated on the 100-260 metres wavelength via a 120-foot aerial. Power was provided by a 6-volt accumulator giving a transmitted output of 30/40 watts.
First World War British W/T Ground Set, c. 1917
It was based on a crystal receiver operating on the 120-700 metre waveband of the type used during 1917-1918 by the Royal Flying Corps (RFC) and the fledgling Royal Air Force (RAF). The equipment was used to communicate with night bombers and in training bomber pilots in the United Kingdom: It was also used in artillery spotting duties. The Mark III was retained in service by the RAF into the immediate post-war years.
To speed up aircraft radio system development qualified wireless engineers were now rapidly given commissions in the RFC. The Experimental Marconi Company experimental section at Brooklands in Surrey had been formed in early 1911 and it was now hurriedly 'taken over' by the RFC in 1914 and turned into a wireless training school for pilots and engineers.
Brooklands had already been established as the ‘home’ of British aviation, and it was also the site of the Brooklands motor racing track built in 1906/1907 by the Honourable Hugh Locke King, on his own land near Weybridge in Surrey.
The first ever aeroplane flight in England had been made there by A.V. Roe in 1908. On 22nd July 1911 the Daily Mail Round-Britain Air Race had started from the Brooklands circuit and in 1912 Vickers opened a flying school. But now the world was at war and both motor racing and sport flying had ceased.
The new ‘Airborne Telephony Research Department’ never really formed. Captain (later Major) C.E. Prince, then serving with the Westmoreland Cumberland Yeomanry, was simply sent down to Brooklands to ‘co-operate’ with the Flying Corps. Despite his pioneering work Musgrave had already returned to the Army and by 9th January 1915 he commanded the 104th Royal Field Artillery Battery with the rank of Major. In March 1915, he was on staff with the 1st Army in France, but was wounded on 10th August 1916 and had surgeries which required recuperation for many months. He was killed in action on 2nd June 1918.
At Brooklands Captain Prince had excellent credentials for the job, having joined the Marconi Research staff in 1907, he had organised the first demonstration of telephony for Marconi in 1910, and later demonstrated telephony using valves between the Marconi New Street works and his Chelmsford house in 1914.
Under Prince’s command on 1st April 1915 No. 9 Wireless Squadron was re-formed at Brooklands. This squadron would subsequently form the basis of the Royal Flying Corps School of Wireless. Before the war an operational airborne transmitter had been designed by R.D. Bangay of the Marconi Company’s Field Station Department, but the more difficult problem of reception in the noisy cockpits of the early flying machines had not been satisfactorily solved.
The Brooklands ‘Wireless Testing Park’ was formed with the prime aim of developing practical wireless telephony (speech transmission instead of telegraphy - Morse code) for ground to air wireless communication and a team of engineers was assembled to find a solution to overcome the barrage of cockpit noise. The primary concern of these scientists was to replace the existing spark gap transmission with continuous wave sets based on the new valve technology and, in particular, the triode valve.
Major-General ‘Boom’ Trenchard, commanding the Royal Flying Corps, laid down his requirements for a system of air-to-air and air-to-ground radio telephony. A one-mile all-round range was a minimum, no adjustments to the transmitter when in operation, and only one tuning adjustment allowed on the receiver. Perfect speech quality with one hundred per cent reliability was demanded, and the maximum aerial length was 150 feet, to be replaced by a fixed aerial if possible.
Given the state of technology at the time it was a tall order, but the RFC desperately needed the wireless telephone to work in the air. Major Prince was told to do it, but no one was quite sure how.
At the outbreak of war Prince had been working on developing a continuous wave valve transmitter for airborne use. From this the idea of a telephone set was a logical step, but one which presented many obstacles before its practical realization. In the summer of 1915 success was achieved when speech from air to ground was obtained at Brooklands over a range of about twenty miles using a wavelength of 300 metres; the trailing antenna was 250 feet in length. For ground-to-air communication wireless telegraphy Morse code was still used.
Prince and the team continued to work desperately to evolve a practical system. At Brooklands, new Wireless sets were continually being designed, tested and often immediately scrapped. Microphones were either too insensitive or too sensitive and the carbon granules inside them were subject to the heavy vibration from the aircraft’s engine. Copper long-wire aerials, weighted at the far end, were often forgotten when the aircraft came in to land, and the trees around the aerodrome soon became draped with them, to the annoyance of the technicians and the men who had to climb up to collect them.
Prince decided that he now had to bring in the best men he could find, working under his control. In the early days of the war the Marconi Company was the only source. To speed the development process highly qualified and talented wireless engineers from all over the country were commissioned as officers and Prince was soon joined by Captain Whiddington, Captain J.M. Furnival, Lieutenant (later Major) R. Orme and Lt Edward Herbert Trump. Another young military engineer who joined Prince later went on to play a key role in the birth of British Broadcasting. His name was Captain Peter Pendleton Eckersley.
Peter Eckersley was sent to the training school at Brooklands as an RFC wireless equipment officer in 1915, and remembered that Prince was to give many brilliant lectures on the intricate workings of the valve. He could actually make the device seem a friendly thing, that functioned solely for the engineer's special pleasure. In reality the valves of the day were often vicious and troublesome. However the core of the Marconi Company’s research effort was now dedicated to the continued development of the thermionic valve. It was the future of radio. At the outbreak of war the valve still a very crude device, each filament being handmade, and each glass envelope individually blown. The presence of residual gases inside these early valves also made them unreliable and short-lived.
The Marconi 1913 Type C valve was a soft low vacuum triode valve, with a lime-coated platinum filament, designed by H. J Round of the Marconi Company and manufactured by Edison Swan. Early examples of these valves had to be coaxed into operation by holding a lighted match under the top glass pip to assist the valves little electric heater. Indeed surviving examples still show these burn marks. The long top pip of the valve actually contained a small piece of asbestos, which when warmed released a gas that made the valve work much better. Signal strengths could be greatly improved by stroking the valve with a match flame, but conscientious operators apparently lost all sense of pain in fingers that soon resembled well done sausages and a new wartime affliction was born – ‘Burnt sausage fingers’.........
In 1913 an American scientist, Irving Langmuir, described how to achieve a near-perfect vacuum. Coupled with this, Captain H.J. Round now used his pre-war work to produce a new generation of valves, for the receiver and the transmitter. The Brooklands engineers now had access to the new Marconi Type Q valve, developed in 1916 and its companion valve the V24, also designed by Round, probably a year later.
Marconi V24 Valves (MWT)
Round’s new Bright emitter Type Q valve was a reliable general-purpose receiving valve. Its key features were small size, as Round had airborne applications in mind, and as a high impedance valve, it was used primarily as a detector. Like all early Marconi valves, it was made originally by the Edison Swan Company, but after 1919 it was amongst the first valves produced by Marconi-Osram in 1919.
The Q valve and the V24 looked very similar, the difference being mainly in grid construction which was a fine mesh gauze carried on two glass beads through which the filament leads passed. The V24 had a lower impedance for use as an RF or low-power AF amplifier valve. It was a long way from requiring burnt sausage fingers.
The technical problems that had to be overcome by the engineering team to achieve reliable speech transmission systems were immense, but the new valves showed the way ahead. But some of the problems that faced Prince at Brooklands were not technology based. He continually battled with the then existing regulations that stated that all communications work for the Royal Flying Corps had to be undertaken by the Royal Engineers. Relationships between the two organisations had already broken down as Prince had little regard for the stolid and unimaginative approach of his military rivals.
Now the problem became serious. The regular wireless technicians of the Royal Engineers had developed a great dislike for the new Marconi personnel who they considered ‘hostilities only’ men, essentially part time soldiers. They especially disliked their unorthodox ways of doing things. Things reached the point where Prince was more than once called in to settle ridiculous inter-unit disputes. The result was that in August 1915 most of the wireless research work was sent to an establishment at Woolwich, and the RFC wireless staff were despatched to a new site at Joyce Green.
The move was at first welcomed. Despite its pre-war success the Brooklands aerodrome was really unsuitable for training and testing as it was located in the centre of the 4,730 yard long (100 ft wide) motor racing track. On three sides there were high tension cables and to the east two 95 feet high chimneys. The small town of Byfleet lay in the south-west corner, Weybridge was to the north and it was close to the railway station and main line.
Despite this Brooklands continued as a pilot training school and by late 1917 the Brooklands School had an output of 36 fighter pilots per week, fully trained in the use of wireless telephony equipment.
Joyce Green in Kent is located between Dartford and the River Thames. This airfield had been built in 1911, again by Messrs Vickers Ltd. to test aircraft built in their Erith Works. In reality, like Brooklands, Joyce Green was also an unsuitable site for a pilot training airfield as there were numerous drainage ditches crossing the Dartford Salt Marshes. However at the outbreak of war, Joyce Green became an ‘air defence’ airfield to house a permanent RFC unit (No. 6 Wing). In mid April 1915, No. 39 Home Defence Squadron was formed bringing together all units and detachments detailed for anti-Zeppelin raid duties in the London area.
Hangars, workshops and ground staff quarters were erected at the northern edge of the landing field alongside the Long Reach Tavern. The work was completed in early 1915, and the first occupants were No. 10 Reserve Squadron with a variety of aircraft including Henry Farman’s, Vickers FB5 and FB9, DH2 and FE8 machines. The role of this unit was to receive pupils from preliminary training schools for final training for their wings. Each course consisted of about 20 pupils and lasted two or three weeks. This included time spent at Lydd where aerial gunnery was practised at the range at Hythe. On gaining their wings the young pilots would get a 48 hour pass before being posted to the Front.
The Wireless Testing Park moved to this busy airfield in August 1915 on a convoy of trucks. Training, testing and wireless experiments then started immediately while around them young men practised war, throwing flour bombs as they tried to make their cumbersome Henry Farman Trainers fly.
Prince now managed to get the ear of an RFC officer who was sympathetic to new ideas, Major Hugh Dowding who, in later years as Air Chief Marshal Sir Hugh Dowding, was to use radio to devastating effect in the Battle of Britain. After listening to Prince and recognising the tremendous importance of radio telephony, he offered his whole-hearted support and asked for a demonstration as quickly as possible.
More often than not, the success of these experiments depended upon Prince’s ability to borrow apparatus from non-Military sources or, as Dowding’s biographer more bluntly put it; upon Prince’s ability to steal the necessary items from Marconi’s London office whilst Dowding distracted the store man with lurid tales about aerial fighting on the Western front!
Prince recalled after the war:
'we..... had to beg, borrow or steal instruments or apparatus due to there being no proper experimental establishment....'
His words were echoed by Major Dowding who recorded that:
'...we encountered the most heart breaking difficulties in connection with Wireless Experiments. The control of Wireless Equipment was at that time vested in the Royal Engineers at Woolwich and they were naturally not conversant with the practical needs of the RFC in the field...'
Although hindered by lack of money and equipment, Prince and his technical team struggled through the summer of 1915, and successfully transformed the very delicate laboratory equipment into a sturdy apparatus which one had merely to switch on and talk.
The development of airborne wireless telephony was really a matter of taking one step at a time. The first and easiest task was to communicate from the air to the ground. The next experiment was communicating upwards, and finally, from machine to machine. The first upward message was sent by Major Prince, calling Captain J.M. Furnival as he circled the field in his aircraft in 1915.
'Hello Furnie. If you can hear me now it will be the first time speech has ever been communicated to an aeroplane in flight.'
The message concluded with a request that the pilot should dip his aircraft to signal if the message was received.
'Hello Furnie if you can hear me dip your wings
The aeroplane, travelling at its top speed of 50 miles an hour, gave 'an obedient lurch.'
The wireless testing park now managed to produce a practical aircraft telephony set towards the close of 1915, known as the Mark One which weighed only 20 lbs (9 Kg). The first air to ground wireless telephony equipment in the world was now operational. Prince made a report:
‘It seemed almost beyond hope to achieve really practical wireless telephony from an aeroplane, but the difficulties have been overcome, and the new set is by no means a toy, or only of scientific interest. A new and amazing power is conferred by it.’
Dowding, much impressed by the results, arranged for Prince to demonstrate the equipment to the Chiefs of Staff in France. So in February 1916 Major Prince crossed the English Channel and demonstrated the Wireless Set Mark One in France to a party of senior officers, including Lord Kitchener himself. Lord Kitchener, deeply impressed, was amazed to hear clear speech on the ground from an aircraft twenty miles away and spoke in gratified terms of the work that had been done.
Despite the successful demonstration Prince had not reckoned on the military conservatism of the day. The upper echelons of the British High Command would not recommend the deployment of wireless telephony, fearing that if the system fell into the enemy’s hands it could be turned against them. In fact, it was not until shortly before the Armistice that the General staff showed signs of relenting. However, Prince and the RFC, defiant of the crass complacency of the General Staff, virtually ignored them and carried on as if nothing had happened. Returning to England, Prince resumed his research.
By May 1916 306 aircraft and 542 ground stations were equipped with old fashioned spark wireless and crystal set receivers. The Marconi Company had undertaken a massive training program that was now delivering qualified operators to the front lines.
RFC Training session
By 1916 all three armed services were depending heavily upon wireless. In the great Somme offensive of June 1916 it was often the sole means of communication between aircraft, artillery and infantry. Mobile wireless stations followed the infantry and the RFC, allowing divisions to communicate with each other. The RFC also began research into how wireless telegraphy could be used to help home-defence aircraft during German bombing raids. In 1916 the RFC deployed Marconi half-kilowatt ground transmitters located on aerodromes in raid-threatened areas.
Trials started in May and pilots reported that signals were clearly heard up to ten miles but at longer distances they weakened. Further adjustments were made and by November clear signals could be heard over twenty miles. Pilots could now be informed about enemy aircraft movements and therefore had a far better chance of successfully reaching them before they dropped its bombs on Britain.
In 1916, former marine wireless officers were dropped by parachute behind German lines equipped with Marconi sets to transmit intelligence reports. In early 1916 the Marconi Company carried out the first valve transmitter tests between an aircraft and Royal Navy units at Scapa Flow. A Short seaplane carried the transmitting equipment, including a large HT battery and the light cruiser HMS Calliope was employed for the six months trial.
Later 75 Royal Navy ships were fitted with similar equipment. Seaplanes were also fitted with transmitting sets for anti-submarine use.
The new light weight of the airborne Marconi sets also allowed Belgian paratroops to be equipped by the Marconi company and dropped behind enemy lines in the first operation of this kind.
On the 23rd August a memorandum was written reviewing the principles of fighting adopted by the Flying Corps since the Battle of the Somme. The operations of this year bore out and confirmed the lessons of the past, and soon a new factor became apparent. Fighting not only extended upwards, but downwards; low-flying machines with wireless co-operated with ground troops, and attacked men, guns, trenches, transport, and hostile aerodromes. The Germans were a year behind in realising the value of wireless in the air; but once they did realise they lost no time in adopting similar methods.
The new system was introduced into the RFC ground networks which now had reliable communication with their aircraft over long distances. The new tactics which this system of squadron control made possible, came as an unpleasant surprise to the German Air Force, whose losses mounted rapidly. The Allied effort in terms of air warfare was now in top gear and they were winning.
However, the prevalent mists and foul weather on the Joyce Green field and the ditches still made take-off and landing very difficult. Also, despite Princes best attempts, four-fifths of the work for the RFC was officially still undertaken by the Royal Engineers Signals Experimental Establishment. Only one RFC officer was allowed on the premises, and he was unable to influence the designs and equipment they now churned out. Of a dozen new sets they submitted to the Wireless Testing Park, all were subjected to damning comments such as ‘a monument of incompetence’ ‘hopelessly bad design’ and ‘a primitive attempt to get round real difficulties’.
As these comments grew to alarming proportions on the desks of the Royal Engineers’ senior officers, it began to dawn on some of them that no matter how competent they might be in military matters, aviation was not really their speciality. The seed took a little time to germinate but eventually it took root and sprouted into something resembling sanity.
It gradually occurred to them that the RFC probably knew a bit more about flying conditions than they did, and that perhaps the weather and state of the ground at Joyce Green was not conducive to the best research. Numerous accidents, several fatalities and the planned formation of the Royal Air Force in 1918, led to the Wireless Testing Park eventually being moved in February 1917 to the newly opened Biggin Hill airfield.
Biggin Hill in Kent, on the east side of the A233, is perhaps one of the most famous airfields of the Second World War through its front line involvement with RAF Fighter Command during the Battle of Britain. Situated on a plateau on top of the North Downs, the site was some 80 acres, approximately 1.5 miles north of the village of Aperfield. Biggin Hill was officially opened on the 14th February 1917 as an RFC Radio Signals Unit. The Commandant of the Experimental Establishment at Biggin Hill was Col. H.B.T. Childs, again in civilian life a Marconi Engineer since 1905.
Shortly afterwards a flight of No. 39 Squadron was transferred from North Weald to Biggin Hill to form the nucleus of the London Defence Squadron (No. 141). Bristol Fighters arrived on the 8th February 1918.
In 1917 Rigid No 9 was fitted with a valve transmitter at Howden, the first such radio installation in a rigid airship as earlier spark sets were thought to be too dangerous because of the stored inflammable hydrogen. Subsequently all British dirigibles carried Marconi valve sets and in late 1917 RFC long range night bombers were also fitted with Marconi equipment.
At Biggin, soon to be centre stage in another airborne war, Prince was rejoined by most of his old team when the Brooklands experimental station (now led by Captain Furnival) was also transferred there. Everyone who entered Prince’s work-shop had to sign the Official Secrets Act, and swear the following oath.
‘I … do hereby swear I will not divulge now or at any time hereafter, by word of mouth, writing, photography or any other means, any information regarding 'Wireless Telephony' that I have acquired or may acquire at any time during my employment by the Government, except to persons authorised by my command officer. So help me God.’
This hung in Prince’s office in a plain wooden frame, with the signatures preserved under glass. The wireless engineers requisitioned Koonowla, a local house once used as a Children’s hospital for their new headquarters. The new Biggin Hill team quickly set up a station to further develop air to air communication and speech quality using Prince's pioneering work in choke control for modulation of telephony transmitters, suggested by Captain H.J. Round in 1914.
At Biggin Hill the engineers at the new Wireless Testing Park began experimenting with new designs to enable inter aircraft speech communication. At first these were mostly unsuccessful and had the habit of breaking down at inconvenient moments. Then someone suggested that the original Round-Prince Valve Telephone set of 1915 might be resurrected for a final appraisal, and accordingly the sole remaining set was hunted down and one of the only original Round Valves still in existence was cautiously fitted into the set.
A microphone of very old vintage, the ‘Hunningscone’, was fitted into a cardboard box filled with cotton wool, and to everyone’s joy it worked. The original air-to-ground results which Prince had achieved were once more reproduced, but more importantly the observer’s voice was also heard, although distorted, in a second aircraft some two miles away.
This was encouraging. The radio technicalities themselves were fairly easily solved, but the speech was still irritatingly distorted, and at times unintelligible. Every type of microphone possible was now pressed into service. Diaphragms of mica, celluloid, aluminium and steel were all tried, but to the annoyance of the team, those which worked well on the ground were virtually useless in the air. After countless experiments, however, some small success was had. It was found that one officer, who had undertaken much of the test speaking, had trained his voice to get the best out of a microphone and speech transmission quality was very good. Other speakers were found to produce only gibberish over the airwaves. The secret was clearly good elocution and pronunciation.
Then it was discovered that if the headphones were connected to the transmitter circuitry, so that the operator could actually hear the sound of his own voice, the speaker could alter his speech pattern to aid transmission. Now for the first and only time in history the Marconi technicians also became hatters, designing and making helmets with pouches for microphones, to replace the standard flying helmet of the time.
The testing pilots and operators practised assiduously, improving their results until they felt confident enough to make a flight to France and demonstrate their system to Trenchard and the Air Staff. There, near St Omer, the two aircraft circled the field, one transmitting instructions which were obeyed by the other. On the ground, Trenchard had a receiver so that he could ensure that there was no deception by a pre-arranged scheme.
Officers were given the opportunity of flying as observers and found that they too, could speak and listen to their satisfaction. Trenchard was so delighted with the results that he at once sent a message to the Directorate of Military Aeronautics:
'With regard to the wireless telephone apparatus recently sent here for test, trials have been made with highly satisfactory results. I am very pleased that this problem appears to have been solved and I consider that it reflects much credit on those who have been engaged in the experimental work and the design of the apparatus.’
In August 1917 the RFC also introduced a wireless telegraphy tracking system to intercept enemy aircraft over England. Four BE12 aircraft sent at two-minute intervals in a simple code the number of hostile aircraft, their positions and direction of flight. The following is a RFC report on 31st October 1917.
'Fighters were put on readiness at 22.38. Four pilots briefly saw bombers, which quickly vanished. Two pilots, Oswell and Lucas, flying BE.12 trackers of No 50 Squadron both signalled their sightings back to base. Oswald followed a Gotha flying at 11,500 ft. northwest from Dover. The crew of a Strutter N5617 from Eastchurch picked up the Gotha. They closed in and the observer fired a drum from his Lewis gun. Shortly afterwards they lost sight of the machine.'
For the first officially recorded air-to-ground telephony communication and for the development of the wireless ‘telephone’ Prince was awarded the OBE, a grant of one thousand pounds after the war and the thanks of a grateful Air Ministry.
Tuner Mark III (Receiver), c. 1918
British variable reaction valve receiver operating on the 350-450 metres and 600-800 metres waveband. The Tuner Mark III (Receiver) was carried in British reconnaissance aircraft in 1918, and used to communicated with artillery batteries
A variable reaction receiver operating on the 350-450 metres & 600-800 metres waveband. Used by the BEF for long-range artillery work, R/T and night bombing along with hostile day and night raids. Also used for spotting for garrison guns & ground inter-communications.
By November 1918 the RAF had some 600 aircraft fitted with the new ‘Mark III choke controlled telephone sets’, operating in conjunction with 1,000 ground stations and manned by over 18,000 wireless operators.
It is also tragic to remember that there was an average of 400 casualties per year among RFC wireless operators, rising to nearly 500 lives lost during the months of May to November 1918.