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This is the second of a series of articles by the first Chief Engineer of the BBC and is concerned with the progress of the revolution caused by the invention of the valve, a progress during which he was intimately concerned with the beginnings of broadcasting. In the first article the author gave an account of how the nineteenth century scientists established the foundations upon which pioneering inventors built their systems. In a third article he will round off with some predictions about the future.
Beam and Broadcast
In the early autumn of 1915 I stood on the tarmac of Brooklands Aerodrome next to the late C E Prince and heard him say into a microphone 'Hullo, Ferdy!' ( I M Furnival a pioneer of aircraft wireless, and now (1959) Consultant to Marconi Instruments Ltd.) 'If you are hearing me now it will be the first time that speech has been transmitted from ground to an aeroplane in flight. If you are hearing me, please dip.' The lumbering 'Rumpty', doing its forty-odd knots, fifteen hundred feet above us, gave an obedient lurch; Ferdy had received the speech, strength R9. The incident gave me a particular thrill; it was the first time I had seen the Thermionic Valve in action.
Of the inventions of the twentieth century that of the valve seems to me to be the most important in the sense that it has had a greater effect upon the form of human life than any other. The valve, generator, detector and amplifier of high-frequency currents, made broadcasting practicable and broadcasting, be it of sound or vision, is of mighty consequence. I say this because I believe that broadcasting is the most powerful means of publication so far devised to influence the mind, taste and manners of mankind. I appreciate the counter-claim for the jet engine and the rocket; these assemblies could indeed be more influential in their capacity to destroy mankind, but I decline to match potential horrors against potential delights. Further, I recognize the importance of drugs - softening pain, subduing infections, restoring sanity - but I still maintain the claims of broadcasting as having a paramount influence upon communal psychology.
Still trying to match credit with those pioneers who deserve it can we find, among several, any one of them who could be allowed to say, in the face of fact, 'I gave the world the thermionic valve'? With deep respect for the person who said it I maintain that neither he nor any one single person did so. The invention of the valve, like that of wireless itself, was too big to be borne of a single individual. But names are possible - in the time order, but not necessarily the order of importance of their contributions. I cite Edison, Fleming, de Forest, Langmuir and - a process not a person the 'getter'.
Edison was unquestionably the first to arrange a plate near a filament and to explain unilateral conduction across the space between them (1883); Fleming, informed about the Edison effect and having at his disposal, on the shelf of a London University laboratory, 'Apparatus for Demonstrating the Edison Effect' probably used it, as a relatively stable rectifier which could be used to give a reasonably accurate measure of the value of high-frequency currents -hence, as a natural evolution, the Fleming diode (1904). Lee de Forest was certainly the one who first placed the third or grid electrode between filament and plate (1907), but the action of this grid was not very well explained or, perhaps because of the softness of the valve, was then inexplicable.
I have no precise evidence to support me but I believe that Langmuir first analysed the behaviour of the hard valve which the 'getter' eventually got. In other words it was Langmuir who related gm, μ, and ra, and showed the valve to be a voltage-operated device in which these three parameters played a coordinated role.
The foregoing, set out in such simple outline, may, by the degree of its generalizations, be unfair to those mentioned and neglectful of those not. If this be so then it is because of the difficulty of compressing into a few paragraphs what is a somewhat confusing and often unedifying story of protagonists up-holding flimsy claims in terms of the polemic of vested interests rather than cool and factual analysis. Soft valves, soft thinking? But, with the tolerance of history, no hard words. Whatever may be the truth, the hard valve did appear out of a confused mist and proceeded, from 1914 onwards, to revolutionize the art and practice of electrical communication in all its forms.
It is surely fascinating to look back with wise-after-the-event eyes and watch the inventors of the past teetering on the edge of the obvious. A case in point concerns the use of the valve as a generator of oscillations; in other words the concept that, by positive feedback, the valve could be made to look like a negative resistance and thus overcome the losses in the resonant circuit it sets into oscillation. Lee de Forest described the triode in 1907 but does not claim regeneration until 1912. And simultaneously others, as we see from a famous legal action, had seen the same potentialities long after the appearance of the valve itself.
Thus 'IN THE COURT OF APPEALS OF THE DISTRICT OF COLUMBIA . . . . Before Smyth, Chief Justice: Robb and Van Orsdel, Associate Justices . . . . This interference comes here on appeal by the parties Langmuir, de Forest and Meissner, from the decision of the Commissioners of Patents awarding priority to Armstrong, also appeals by de Forest against Meissner and Langmuir jointly, and against Langmuir individually, for the invention set forth in the following counts' - and then ten or more thousand words in which other famous names came to the fore, notably Franklin and Round (England). A good deal of the evidence concerned 'a beautiful clear tone' which de Forest claims to have produced from his Audion; it seems to have sounded as a syren voice in the ears of the legal pundits who gave judgment in de Forests favour. Howard Armstrong, that prolific inventor, was much upset by a decision which was inclined to stress a somewhat loose description possessing a few months priority against one which was far more, concise if a little later in time.
While still thinking about these time-lags it is also strange to realize that we had to wait several years before we were given the immeasurable benefit of negative feedback, almost as important an invention in its influence upon the valves ubiquity as the positive kind of feedback.
So much for genesis.
In spite of my presence at the Brooklands demonstration in 1915 I spent the greater part of the war in Egypt, Salonika and France looking after spark transmitters and crystal receivers. It was not until late in 1917 that I was appointed to do what was rather grandiloquently described as 'Research', first for the Army at Woolwich and then for the Flying Corps at Biggin Hill. Here I came into intimate contact with the valve, its moods, potentialities, successes and failures.
Soon after the armistice I escaped out of a uniform (a 'war to end all wars' had just been victoriously concluded, what point in remaining in military service?) and joined the Marconi Company. In a short time I became Head of the Experimental Section of the Designs Department, the laboratories being housed in an army hut in a field near the village of Writtle which is in turn near Chelmsford, where the Marconi factory was and is located. A claim to fame, before ever broadcasting came to increase it, lies with the fact that I played a considerable part designing both the first aircraft wireless telephone equipment, used extensively by Imperial Airways, also the Croydon ground station. Who remembers 'Croydon calling' and its speech heard against a background hum as loud as any produced in his receiver by the most amateur of amateurs? The hum was purposive; it made tuning in by the pilot all the easier.
Two important events accompanied my service at Writtle, first the setting up at Chelmsford of a powerful long-wave telephony transmitter and secondly the regular broadcasting service from 'Two Emma Toc, Writtle'. I will not labour detail, the facts are well known and have been set out elsewhere; I would prefer rather to generalize than to indulge anecdotage. Suffice it to say that the initiative due to H J Round and W T Ditcham, in setting up the powerful long-wave telephony station at Chelmsford circa 1919 stimulated the wireless amateurs to petition for a regular broadcasting service, and that permission for this to be set up, on the limited scale of half an hour a week, resulted in the Writtle station and the Writtle programmes, a service which anticipated that started by the BBC, in November, 1922, by some eighteen months.
A diminishing number of wireless amateurs and others attracted to the hobby of building 'wireless sets' will remember the programmes from Writtle as being frivolous, I would prefer the description 'gay'. Perhaps the more remarkable aspect of the Writtle transmissions was the staff that fostered them. This comprised in the order they joined me after I became Chief Engineer of the BBC, the late H . Kirke, CBE, sometime Head of the Research, and subsequently Assistant Chief Engineer; B N MacLarty now Engineer-in-Chief of the Marconi Company, the Hon. R T B Wynn, CBE, now Chief-Engineer of the BBC, and Sir Noel Ashbridge who was for so long the Corporations.Chief Engineer and subsequently Director of Technical Services.
A notable group, the members of which conducted the first regular broadcasting service, from station 2MT, Writtle, some eighteen months before the BBC was formed. Left to right, standing, B N MacLarty, the late H L Kirke, R T B Wynn, H J Russell; seated, F Bubb, N Ashbridge, P P Eckersley, E H Trump and Miss B Beeson.
An accompanying group photograph recalls a collaboration which I dare to describe as unique. In my first article I described how, when still a schoolboy, my subsequent career in wireless was largely determined by the tactile excitements of brass and ebonite: it was a similarly sensual experience which caused me to swerve from occupations concerned with the less romantic aspects of radio to one devoted to the service of broadcasting.
It must have been in the early autumn of 1922, before the formal creation of the BBC in November of that year, when Station 2LO broadcast opera from Covent Garden. Up to the time when I was converted to a belief in broadcasting, the wireless telephone as such had to me done little more than intrigue my technical intellect, its applications were seemingly prosaic, while our Writtle broadcasts seemed to be no more than the aphrodisiac of a hobby ('keep your boys at home'). But the moment of revelation, the moment when I heard the opening bars of the opera, and was in two senses transported, then the potentialities of broadcasting were seen so vividly and so completely that thereafter all attempts to realize them have been to me tinged with disappointment.
The experience must be seen as mystical, as such I have unashamedly tried to describe it; its residue caused me, in prosaic contrast, to frame what I termed the BBCs technical policy; I still believe in it and I still believe it has not been fully implemented.
In sum it is my belief that 'The Programmes the Thing' and that the mechanism which reveals it must be subservient to the art which creates it. To conclude from this that the policy so described does no more than demand realism in reproduction begs the question so long as the term realism is not defined. You do not have realism, as it sometimes is defined, when, for example, a single source of reproduction canalizes a widely diffused source of programme. A two-dimensional representation of a three dimensional subject, such as is seen in a painting cannot be said to demonstrate realism in one interpretation of the term. But the artist who knows his job knows how to make a virtue of necessity and uses the very limitations of a medium to make his art more realistic - in other words, to make the impact of his art upon the sensibilities of an audience more pronounced than realism, prosaically defined, could ever do.
Having said that the Programme is all important it might next be said, stressing the plural, that the Programmes are more so.
A hobby-horse cannot be ridden to death, since,lacking a rider, it is already dead. I shall now attempt, in a brief spell, to resuscitate my old nag. To do so demands an explanation why I believe that this stressing of the plural of Programme is so important. I was, I am and I believe I always will be convinced that the technical method by which broadcast programmes are distributed pays greater respect to the art it serves as, within reason, the number of different programmes it offers, simultaneously, for the individuals choice is the greater. This conviction determined me, after I had left the BBC (1929), to do all I could to proselytize and develop rediffusion, i.e., schemes whereby programmes are distributed through wire networks rather than by radio. Need I stress the limitation of radio in being very spare of channels in the frequency bands available, while relatively the wire suffers no such restriction?
During the late twenties and early thirties the Post Office, the BBC and the Radio Trade more or less openly opposed the development of rediffusion; in spite of so formidable a combination it grew, and when given a chance, goes on growing. This fact reaffirms an unshakable conviction that a majority want a reasonably wide choice between different kinds of clearly produced programmes.
This proposition might well have been denied when, in the early days, the passion for home-building radio receivers was at its height. Many of my readers must remember those delightful times when they would hear one of the cognoscenti boasting his home-built set and how he 'received Zloik (station in Czechoslovakia, old man) on my Super-woppo-dyne; phones were lying on the kitchen table and I heard the station quite clearly, while I was upstairs changing my shirt'. Well, 'it was swell while it lasted'; it was that rarity a hobby that produced a full-scale manifestation. In contrast you built a model steam engine and the consummation was a smell of meths and a jerky pulling concealed in a pale mist - how different from Zloik 'clear as a bell and no fading, old man'.
The hobby died, the public bought the superhet, the programme was the thing and this gave rediffusion its opportunity.
I cannot refrain from taking this opportunity to air a grievance. Briefly it is that when there actually was a means to prevent the extension of rediffusion the vested interests made full use of it. My friend and colleague Rupert Carpenter and I devised a system whereby four to six programmes could be sent through the electric mains to house-holders who, by the movement of a switch, could select any one of them. There happens to be an Act of Parliament, dated 1882, which forbids the electricity authorities to use their wires 'for the purpose of sending a telegram'. After a demonstration of the practicability of our method it seemed to certain vested interests and their Parliamentary sympathizers that this act was hardly less important than Habeas Corpus. And so, in the 'land of opportunity' (see Press) we were forbidden to prove how right our opponents were when they said, as they did, that our scheme would not work and that if it did it would introduce a 'dangerous new principle'.
The issue requires little elaboration, the proposals we made about it, also about the wider implications of wire-broadcasting received either contemptuous dismissal by Government committees and commissions of enquiry or combative assertions about technical method; funds were even raised to oppose the passage of a bill through Parliament revoking the ancient statute; today, with the impact of television the issue about the method itself is dead but not, I trust, the implications of the story.
I shall not say much here about the more important phases in the development of sound broadcasting, its rejuvenation by VHF, the introduction of the 'Third' (the most notable and admirable of the BBCs innovations), automatic monitoring, the overseas service and its intricacies of switching programmes, so admirably conceived and executed and, above all, television. I excuse this unbalance by remarking that it is all recorded elsewhere whereas in like degree heterodox opinion, which becomes me better, has not. I could not, however, even begin to excuse the dismissal of television and so, since it belongs more to Time Future than to Time Past, I will have a good deal to say about in in my next and last article.
While I maintain that the most remarkable outcome of the invention of the valve is the broadcasting service, obviously parallel developments are nearly as important.
It was said in my first article that, broadly speaking, the first decade of the development of wireless proved it, as a means to link stations separated by world distances, a comparative failure. It was of course the valve that raised the status of wireless as a world communicator so that it became, under the aegis of private enterprise, a competitor with the under-sea intercontinental cable. In order that private enterprise should not become indecently enterprising the Establishment decided to synthesize thesis and antithesis and so brought the Public Utility 'Cables and Wireless' into being.
The invention that brought about the merger was the Marconi beam system whereby it was proved that radio was capable of penetrating to distances of the order of π times the radius of the globe; a globe assumedly well wrapped in an ionized blanket. It was his ability to see the wood, without confusion of trees, that, just after the conclusion of the first war, made Marconi say, 'Now that we have the valve why don't we try short waves again?' The sentence implies an appreciation of the signal-to-noise ratio; the higher the frequency of the signal the less the noise. On the other hand the shorter the wave the greater the overland attenuation. Before the aerial currents could be amplified, short-wave ranges were limited to very short distances; once the more feeble but less interrupted signals could be amplified the overall gain was, to say the most, fantastic.
I have never been able to find out whether and if so in what degree Marconi was driven to follow his hunch, so neatly stated, by the mass observation of amateurs; it is surely fitting to remember that these keen experimenters, driven away from the medium-wave gamut, did prove, by their skill and patience, that, on the lowest terms, an investigation of the commercial potentialities of short waves was well worth making. We may also note that the less imaginative authorities were still tied to lower frequency and higher power and still higher aerials.
In commending the beam system we should pay tribute to the genius of C S Franklin who designed the transmitters, aerials and receivers, and to T L Eckersley whose original work on the physical properties of the ionosphere made it possible to match optimum frequency with world paths and diurnal times.
I am drawn, in these concluding paragraphs to hover on the edge of prophecy; a giddy state and therefore exciting. Boldly stated, it is that point-to-point communication over ocean distances will eventually and as to the greater part be made by cable, while overland communication, as to a considerable part, will be consummated by radio. I stress ocean distances meaning communication where oceans get in the way; there is no need to define the term overland, it means over land. I stress also that it is point-to-point communication that is in question; obviously radio is the only viable method of communication for mobile services.
To expand this thesis we see already how the telephone and telegraph service between, in effect, Europe and North America has been improved by substituting cable for radio. We learn of plans to bridge the Pacific and link the Commonwealth by supplementing this ocean cable by another spanning the Indian Ocean. We know that when the transistor and its associated components become more reliable that great benefits will be conveyed to the ocean cables. We can foresee intercontinental television exchanges (which are almost impossibly expensive when relying upon a radio link) becoming an everyday occurrence when there are sufficient cables to carry them.
As to overland communication by radio there are in operation today many systems, the wave frequencies climbing into and above the four thousand mega-cycle landmark. Line-of-sight transmission, from hill-top to hill-top, invites shorter and shorter waves and as the systems develop and according to the nature of the terrain we may see them, as we do today in various parts of the world, supplanting the coaxial and multi-quad cables by means of which many hundreds of messages are sent simultaneously through the same link. There seems to be, at first blush, something of a paradox if radio, hitherto used as an ocean bridge, should give up its role in this respect and take on another where, superficially speaking, the physical conductor would seem the obvious link. For overland communication the paradoxical aspects may fade, as does radio, when it is seen that signalling by refracted and reflected waves has a hazardous aspect when compared with a conductor which guides the waves to their destinations.
It may seem as if this adumbration of possible future developments is outside the terms of reference of an article headed Time Past. But no! Time past has seen the wide use of radio for point-to-point communication over land as it has also seen the introduction of the telephone cable bridging the Atlantic; the facts are there; all that has been done, in a time future category, is to postulate the continuation of a tendency already manifest in Time Past.
But 'Amarath an Amarath succeeds' ; a new form of multi-electrode amplifier - the transistor - is already taking up the work begun by its forbear the thermionic valve.
I end as I began by stressing the importance of the invention of the valve without which the Time Future of telecommunication, which I hope to glance at in my next article, would not, in all probability, be worth writing about.
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