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THE experiment of conducting a church service entirely by wireless was successfully carried through in Norwich on Sunday, July 12th.
St. Bartholomew's, Heigham, was filled with people who took part in the evening service broadcast from St. Martin-in-the-Fields, Trafalgar Square. The congregation remained seated during the singing of the hymns, but knelt during the prayers.
Twice during the sermon the St. Martin's congregation were heard laughing at the preacher's sallies.
At the expense of fitting a small broadcast receiver any vessel in the vicinity of the British Isles may now obtain weather forecasts for the succeeding 12 hours as a result of a new arrangement made by the Board of Trade.
Provision has been made for broadcasting certain portions of the weather Shipping Bulletin by coastal stations and by the B.B.C. The Daventry station broadcasts the Meteorological Office forecasts at 9.30 a.m. (G.M.T.), and the stations at Liverpool, Bournemouth, and Newcastle transmit local forecasts between 9.20 and 9.35 p.m.
(web note: a description of a little byway of radio technology. In 1904 there had already been a demonstration of locating the direction of a ship by means of a reflected signal, but at that time its position or range required two transmitters and triangulation. The frequency used in the demonstration described below was 50Mhz, known today as suitable for VHF Long Distance Radar. Radar came along later. No satellites to obtain positions in 1925...)
Demonstration of the Revolving Beam System
THE revolving beam station at South Foreland formed the subject of an official visit by representatives of the Government and certain shipping companies a few days ago. At the invitation of the Marconi Company, the party visited both the South Foreland station and Senatore Marconi's yacht, the Elettra, and were able to participate in a demonstration of the revolving beam system during a short cruise extending from South Foreland to Southend.
The demonstration was conducted by Mr. C. S. Franklin, and the guests were entertained personally by Senatore Marconi.
As this is the first occasion on which the public has been admitted to view the South Foreland station, it is an opportunity to describe the principle of the system and to give one or two details regarding the method adopted for transmitting the beam signals.
The Beam Principle
The South Foreland revolving beam consists essentially of a directional transmitter combined with a reflector
which can be rotated and, therefore, transmit in any one direction as required. By arranging a code of signals in such a way that they are transmitted automatically in succession as the radiating or aerial system revolves, it can be so contrived that the same signal is always transmitted whenever the transmission is in any one direction, so that vessels at sea when they receive the distinctive signal know precisely in what direction the beam is being transmitted and can deduce. their own position.
It is, of course, essential that the transmission of signals should correspond precisely with the changing position of the aerial system as it rotates.
The principle of a rotating directional transmission which sends out distinctive Morse signals as the direction varies has already been made use of, and it is interesting to recall that this method was adopted during the war (1914-1918) to provide accurate bearings to Zeppelin airships in flight. The application of the idea, however, to the very short wave beam system has important advantages: the wavelength used is stated to be 6.09 metres, and it is claimed that the transmission can be projected in as narrow a beam as 15 degrees, and, due to the reflector principle, in one direction only. The use of such a wavelength ensures that no interference will take place with ships conducting their ordinary traffic, while the narrowing of the beam of radiation should reduce the power necessary to be employed at the transmitter, as well as improve upon the reliability of the bearings taken.
The power supplied to the anode of the valve of the South Foreland transmitter is approximately 280 watts. The leads to the aerial system from the transmitter are carried through insulated wires in an earthed metal conduit. The rotating aerial system comprises a number of energised aerials arranged in a straight line, together with a number of reflecting aerials arranged in a line parallel to that of the energised aerials.
The reflecting aerials are stated to be spaced a quarter wavelength from the plane of the energised aerials. Very careful attention has to be paid to the precise tuning both of the energised aerials and the reflecting aerials, and provision is made for tuning adjustments by the inclusion of a spiral inductance coil at about the centre of each of the vertical wires.
Transmitting the Signals
The aerial structure is, of course, arranged so that it rotates continuously at a uniform speed and sends out distinctive signals indicating the direction at which the aerial is pointing at that moment.
The transmission of these distinctive signals is arranged automatically by means of plates representing the Morse characters, which are mounted on a large ring carried by the revolving structure,
These plates actuate a contact mechanism as the structure revolves and so key the transmitter automatically. The present aerial system is supported on a wooden superstructure, but it is stated that this is experimental, and, in final form, steel towers will be set up at either end of the structure to support the aerial system.
A Wireless Lighthouse
The system may well be described as a "wireless lighthouse", but it has the advantage that whereas in foggy or stormy weather the illumination of a lighthouse is often seriously reduced, such weather conditions will not affect the efficiency of the wireless lighthouse.
The system can be adopted by small vessels because the receiving apparatus is very simple to handle and can be made extremely compact.
In the case of vessels already equipped with wireless, the beam receiver would be an entirely independent unit. It is stated that the range of action of the South Foreland station is approximately the same as that given by a lighthouse under satisfactory weather conditions.
On Senatore Marconi's yacht the Elettra reception of beam signals is carried out by means of two receiving aerials mounted one at each end of the bridge. A length of cable connects the aerial system with the receiver, carrying both aerials to the chart room where the receiver is located. A choice of two aerials is given so that for longer ranges the ship itself shall not provide a screen and interfere with reception.
It is stated that the South Foreland installation, when under test, has given signals to the Elettra up to 100 miles over sea.
It is, therefore, easy for a ship in a fog to make out the exact direction of point A, whereby, by the conventional number of taps or rings, she will be able to discern either a dangerous point to be avoided or the port or harbour for which she is endeavouring to steer."
Unfortunately, however, that was then possible only in theory; for there were no means of producing Hertzian waves of the persistency and frequency that were essential.
The method and the means are two quite different things. The same remark applies in almost the same degree to the proposal made by Stone in 1901, according to which "ships when approaching each other at sea may receive warning of their proximity to one another, and each ship may determine the bearing of the other, as well as such other information as they may wish to communicate, as, for example, the course steered and the speed."
It was not until 1907 that Bellini and Tosi evolved a direction-finding method which could render any useful service to navigation with the means developed up to that time; and even that service was so greatly limited by the crudity of the means available, that it was scarcely worth while.
Finally, some seven years later, when, largely due to the ingenuity and perseverance of Round and Wright, the Bellini-Tosi method became of great value- particularly for military strategic purposes.
However, its cost, delicacy, and intricacy are factors which are still detrimental to its general adoption as an aid-to- navigation. It was the evolution of the triode, or thermionic valve, as an efficient receiving device, which made possible the practicable development of the Bellini-Tosi system; and it was the use of the same device as a generator of oscillations of very high frequency and unvarying persistence which opened the way in 1914 for the application of Marconi's proposal of 1899, and rendered possible the "beam" aid-to-navigation stations recently installed at Inchkeith and South Foreland.
It yet remains for someone to apply like means to Stone's proposal of 1901; and herein lies the point of this story. bridge-to-bridge telephony.
No observant person who has been shipmates with a modern direction-finder will doubt its utility; neither will he question the general need of such a device. Yet few ships, comparatively speaking, are so equipped. The reasons are many, and one of them is that shipowners are loth to adopt devices which cannot be operated by their navigating officers; especially if such devices are of only limited use and are regarded as still in a process of evolution.
There is, therefore, a great need of an equipment which will at once provide (a) automatic directional warning of the near approach of a ship, and (b) automatic warning to the approaching ship. Moreover, since the provision of such equipment now presents no technical difficulties, and the same equipment may be designed to provide also bridge-to-bridge telephony, there seems to be every reason why it should be forthcoming.
The theory of such an equipment was outlined by John Stone some twenty-four years ago in the specification of U.S. Patent 716,955 (British Patent 28,509/02), and, as has been indicated, the means for putting it into effect have long since been available.
It would be constituted as follows : the transmitter should have a wavelength of about 5 metres and be rated at 50 watts, and a vertical self- supporting oscillator. The receiver would be connected between two vertical self-supporting aerials, half a wave- length apart, mounted at equal distances on either side of the transmitting aerial and adapted to be rotated automatically about the latter.
Operating Procedure
On the approach of fog, the officer of the watch would start the transmitter, preferably by means of the same switch which is usually provided for starting the auto- matic steam fog~signal, which action would also start the rotation of the receiving aerials and throw the associated gear into operation.
A junior officer or apprentice would at once stand-by the receiver and either listen or watch for an incoming fog-signal -arrangements could readily be made for either sound or light signals-while watching the progress of a pointer around a compass card. The pointer would indicate the angle made by the rotating aerial with the ship's keel.
Upon receipt of a signal he would log it and its bearing, and report it to the officer of the watch, who would take steps accordingly. Obviously it would be advantageous if the transmitter were adapted automatically to signal the ship's course and speed, and this could readily be done.
Should the officer of the watch desire to speak to a ship whose warning signal he had received, he would simply speak into a microphone which would be coupled to his transmitter, the receiving aerial being stopped in the place of the observed direction of the ship to be spoken. For this purpose he would not be required to leave the bridge.
This equipment would also be useful in the event of a ship requiring to speak one of its own boats, in fog or otherwise; moreover, it would greatly help such boats to locate the ship in fog.
The efficiency of any scientific aid-to-navigation depends largely on the facility with which it is used and the confidence that may be placed in it.
With the arrangement suggested herein, navigators would be holding bridge-to-bridge conversations every day, and would thus have ample opportunity for checking its accuracy and dependability.
Lord Burnham, who is President of the Imperial Press Union, entertains no doubts as to the reciprocal benefits which broad- casting and the Press can confer upon each other. Ina recent interview at Sydney, Australia, Lord Burnham stated that he had found that the brief broadcast news bulletin, in announcing happenings of importance, roused public curiosity, with the result that newspapers were bought for the purpose of learning details. The prime necessity is, of course, that the broadcast message -should precede the newspaper report; a "stale" broadcast bulletin is boring in the extreme.
(History note: The first transatlantic telegraph cable was laid in 1858 but only worked for a month. A longer lasting cable was laid in 1865. It was then a long wait until 1955 until the first transatlantic telephone cable was laid. Radio was used until then... read on).
THE announcement that a Transatlantic telephony service is about to be started has been received by the public with some surprise. It has long been known that experiments were in progress, yet it was not expected that the system would so rapidly reach the state of perfection necessary for commercial service.
That Transatlantic telephony was only an afterthought when designing the great Rugby Station is evidenced by the layout of the masts. The original intention was to use the entire mast system for the telegraphy transmitter, but with the possibility that a Transatlantic telephony service might be developed led to the installation of the gear at the Rugby Station.
Secrecy
Long-distance wireless telegraphy, however, as a commercial possibility dates back to December 1922 when the International Western Electric Company, in conjunction with the Telephone and Telegraph Company of America, demonstrated wireless telephony communication between Broadway, New York City, and their works at Southgate, near London. The distance was about 3,200 miles, and the transmission lasted for over two hours with perfect quality and without interruption or parasitic noise.
Many problems have had to be solved. The handling of high power, the need for secrecy, the use of only a limited wavelength band, and the provision of simultaneous two-way working without interference between the transmitting and receiving apparatus. The side band system is employed, the interception of the signals being difficult and requiring elaborate equipment. It is significant to note, moreover, that, except during the first Transatlantic experiments from Rugby of nearly a year ago, amateurs have lost sight of the transmissions.
Duplex Working
For duplex working the stations at Rugby and Rocky Point in the United States transmit the outgoing messages, the receiving sets being installed at Houlton, Maine, and at Wroughton, near Swindon. It is believed that the system is not strictly duplex telephony, but that the receiver is rendered inoperative when the transmitter is being modulated.
The effect that the new service will have on business and everyday life is likely to be far reaching, and full credit is due to the Post Office authorities for the enterprise they have shown in securing for England the first European link of what will probably become an inter-Continental service with America.
It is to be hoped that the British Broadcasting Corporation will avail itself of the telephony link by providing for listeners at an early date a programme relayed from New York as a means of demonstrating the success of the new service.
B.B.C. in liquidation As a matter of formality under the Companies Act, a meeting of creditors of the British Broadcasting Company is to be held at the Hotel Cecil on February 7th. Sir John Reith, the liquidator, states that all creditors have been or will be paid in full.
A BUDGET BROADCAST?
Whlen Parliament reassembles Captain Ian Fraser, M.P., will raise the question of broadcasting the proceedings of the House. It is suggested that the Budget would be especially suitable as a subject for broadcasting.
TRANSATLANTIG TELEPHONY SERVICE.
A further extension in the Post Office Transatlantic Telephony Service took place at 1.30 p.m. on Saturday last, when the service became available to and from all places in England and Wales. Simultaneously the service was extended in America to include the States of New Jersey and Pennsylvania.
LICENCES IN NORWAY.
There are approximately 100,000 owners of wireless receiving 1icences in Norway and the number is increasing daily. Denmark has 92,000.
LINER'S WIRELESS RECORD
The Cunard liner "Carinthia" is believed to have created a wireless record by establishing two-way ship-to-shore communication over a distance half- way round the earth. The "Carinthia", which is now on a voyage round the world, accomplished the feet by exchanging messages with the New Brunswick station (N.J.) while 12,500 miles away.
AN OSCILLATOR IN PETERBOROUGH
Alleging that some unknown person is deliberately oscillating and thereby spoiling broadcast reception, a number of listeners residing within three and four hundred yards of each other in the Fletton Avenue district of Peterborough have sent an appeal to the B.B.C. for advice and help.
A NOTABLE ANNIVERSARY
On February 2nd, 1896, the young Guglielmo Marconi arrived in England, bringing with him the crude apparatus which formed tlie nucleus of practical wireless telegraphy. In the same year he took out the first patent for Hertzian Wave Telegraphy (No. 12059 of 1896) according to which, besides many improvements in the apparatus, one end of the Hertzian dumb-bell oscillator was buried in the earth and the other end elevated in the air.
In July 1896, before officials of the Post Office, he conducted successful experiments over a distance of 100 yards, and shortly afterwards established communication between points 1.75 miles apart.
Welsh station still in demand
Following the example which is being set by several Welsh towns, the Swansea Education Committee is supporting a motion in favour of erecting a broadcasting station catering solely for Wales in order to maintain Welsh individuality and culture.
RADIO "LIGHTHOUSES"
The Liverpool Steamship Owners' Association, in their annual report for 1926, draw attention to the fact that, although the introduction of wireless has been of the greatest importance in the protection of shipping routes, the extent to which radio "lighthouses" can replace general lights has never been properly considered.
Neither the Board of Trade nor the Admiralty has any effective control over the authorities now charged with the administration of the lighthouse services, all such matters having to be brought under the review of Parliament.
WIRELESS AND COUNTY POLICE
How a northern county police force in an industrial district is using wireless for relieving the telephone system is explained by Sir Leonard Dunning, the Inspector of Constabulary, in the annual reports of police inspectors to the Home Office. The reports are published by H.M. Stationery Office.
"Time lost in the transmission of appropriate messages via exchanges is obviated," writes Sir Leonard, "and isolated detachments on special duty can be provided with means of communication. I have been surprised to find that transmitting and receiving sets can be so inexpensively established.
"Communication by wireless telephony has also been maintained successfully over shorter distances. In my opinion, this development has great police possibilities for use in wide districts."
Broadcast [Receiving] Licences
The number of radio receiving licences issued during the year 1926 was 2,178,000, compared with 1,602,000 in 1925.
ANOTHER CRITIC OF BROADCASTING
The latest addition to the ranks of the critics of broadcasting is Mr. H. G. Wells, who, in a recent edition of one of the Sunday papers, occupied the greater part of a page to tell us why broadcasting is a farce and why its decline and eventual fading out is inevitable.
At the conclusion of the article the Editor promises that "another vigorous article by H. G. Wells will appear on Sunday week."
When we had reached that editorial appendix after having laboriously read through Mr. Wells's entire article, we could not help wondering whether the Editor had not been a little careless in his choice of an adjective, for we cannot remember having read anything by Mr. Wells previously where the use of this adjective would not have been more appropriate than in describing his article on broadcasting.
We had hoped when we came to read the article that at least we should have been given some strong points against broadcasting sufficient to provoke a desire on our part to argue, but perhaps the strongest case which Mr. Wells makes out is that music in the home can be obtained equally as well from a gramophone or pianola as from broadcasting, and that in the former case you can make your own selection of the music you wish to hear.
In our opinion, it is so difficult to compare these two that the point is scarcely worth discussing, even if we omit the consideration of cost, which in the case of the pianola and gramophone, with the addition of records, places these instruments beyond the reach of a very large proportion of the population.
"But, sooner or later," says Mr. Wells, "boredom and disappointment with these poor torrents of insignificant sounds must ensue. Are there, indeed, any indeefatigable listeners who have stuck to this amusement since the beginning? If so, I think they are probably very sedentary persons, living in badly lit houses or otherwise unable to read, who have never realised the possibilities of the gramophone and the pianola, and who have no capacity nor opportunity for thought or conversation."
A Phantom Army of Listeners.
Mr. Wells makes it quite clear that he himself has no use for present-day broadcasting, but it is surprising that he, whom we are accustomed to regard as having an extraordinarily complete knowledge of human nature, should now be "at a loss to imagine any sort of person becoming addicted to listening-in as a frequent entertainment," when, if Mr. Wells would go to the trouble of looking up the facts, he would find that the number of listeners is steadily increasing, and the copies ot the wireless programmes sold weekly and the correspondence received at the B.B.C. headquarters are alone a guarantee that the future of broadcasting will not present the amusing picture which he draws of the service continuing to operate for the entertainment of a phantom army of listeners, "the last living listeners having dispersed and gone to other things."
[2014 note- with millions of tracks available for streaming online today maybe there is now a move away from broadcast radio? There is still a need for physical media to cater for true minority interests which streaming sites do not cater for (yet?).]
A SCREW-DRIVER HINT Screws in awkward and obscure corners may require long screw-drivers for tightening up.
Often there is difficulty in engaging the end of the screw-driver in the screw slot, particularly when the screw-driver is inclined to the axis of the screw.
The direction of the screw slot can be seen; but it is difficult to tell which way the grinding on the screw-driver is pointing if the lighting is poor.
To overcome this difficulty, a slot should be cut in the head of the handle coinciding with the direction of grinding, as shown in the sketch.
A. G. E
FOR the second time in the short history of broadcasting it has been left to Holland to steal a march on this country and, in fact, on Europe generally. It will be remembered that some long while before broadcasting here was introduced British amateurs were accustomed to listen to the Dutch broadcasting station at The Hague which, with the call-sign PCGG, sent out regular Sunday afternoon concerts, mainly for the benefit of listeners here.
Now again Holland sets the example by leading the way in short-wave broadcasting. On the 15th of March the station PCJJ established at the Philips Lamp Laboratories at Eindhoven, in Holland, communicated by wireless telephony with the Dutch station at Bandoeng, in the Dutch East Indies. The transmission was carried out on a wavelength of approximately 30 metres.
Heard in Australia
Since that initial success fairly regular broadcasting has been conducted. Now, as we go to press, comes the announcement that the Sydney station, 2BL, has successfully rebroadcast one of the programmes. We congratulate Holland, and the Philips Company in particular, on the enterprise shown in establishing this broadcasting record, more especially so as the purpose is apparently to provide a means for long-distance broadcasting, and advantage has been taken of the peculiar suitability of the 30-metre wavelength.
Will Holland's Example be Followed?
It will be of interest to observe whether this example set by Holland will be followed by other countries in Europe. Personally, we should be sorry to see stations established in this country to work on wavelengths of that order unless ample notice were given, for the reason that comparatively few sets in the hands of the public would be capable of listening in to the transmissions. The only application which we can see at the moment for a short-wave broadcasting station in this country would be for the purpose of overseas communication, as we have previously suggested in these columns.
Not a B.B.C. Affair
If such a station were erected it might quite possibly fall outside the scope of the British Broadcasting Corporation and come under the control of the Foreign Office and the Colonial Office.
An Opportunity Neglected
It is a matter for regret that we should so far have neglected to take advantage of the wonderful opportunity which broadcasting provides for communication with the outlying sections of the Empire. When we know that wireless sets are being bought in places as far distant as India and Iraq, in the hope of being able to pick up the transmissions from Daventry once in a while for, perhaps, no more than a few minutes, we can form some idea of the enthusiasm which would be created if a short-wave British station were established in this country of suffcient power to be heard more or less consistently.
SINCE the publication of our last issue matters in connection with Empire broadcasting have proceeded apace. The B.B.C. have made an announcement to the effect that they are immediately undertaking the erection of a short- wave station at Daventry, and they excuse themselves for not having gone ahead earlier on the score that they did not feel justified in spending public money on an enterprise which was only experimental in character.
If that is the correct explanation, it seems strange that they are now prepared to proceed with the station although, to the best of our knowledge, they still have obtained no special authority to authorise the expenditure.
However, even though the step taken is so delayed, we are yet glad to see that action is being taken. Capt. Eckersley has stated that it will be some six months before the station is completed, and a very long time- perhaps years- before Empire broadcasting can be inaugurated.
It seems to us that there is no justification for such a delay. It should only take a comparatively short time to erect a suitable station, and no one expects that the results can be perfect all at once. As we have pointed out before in our early appeals for an Empire station, the Colonies and remoter sections of the Empire would be well satisfied for the time being if a station in this country could give them results equal to those they obtain at present from the Dutch broadcasting station.
It appeals [sic] to us as almost pathetic that on the occasion of our recent celebration of Empire Day a request should have been addressed to the Dutch station authorities at Eindhoven for the Empire Day programme to be broadcast to the British Empire through that station. The request was turned down, and with good reason, we consider, for what possible excuse have we for asking a foreign broadcasting station to distribute a programme of that character to our own Empire when it is merely lack of enterprise on our part which has prevented us from being able to carry out such a transmission for ourselves?
[I don't think this content will upset GCHQ or the NSA - privacy in communications was a thought that arose quite early in radio development. In 1927 communications were moving rapidly from wire to wireless. An interesting if outdated article. The thoughts below on radio propagation for example were not correct. The web site owner once had a radio capable of resolving the simple single side band mode described below, and has heard (but not deciphered) the "chopped up" side band mode later described below.]
Secret Radiotelephony Systems
A review of the problems involved and solutions suggested.
by O. F. . BROWN, MA., B.Sc
THE recent inauguration of the Transatlantic Telephony Service has directed attention to the problem of secrecy in radio communications. Hitherto comparatively little serious consideration has been directed to this matter, partly owing to obvious difficulties of the problem, and partly owing to the fact that where telegraphic communication was concerned the disadvantages of a lack of secrecy could be overcome by the use of code or cipher. Although code words can be employed to a certain extent in telephonic communications, it is obvious that serious inconveniences are introduced by their use.
It seems probable, therefore, that the general use of long-distance radiotelephone services is likely to be prejudiced by the fact that at present portions of the conversations, at any rate, can be picked up by unauthorised persons over considerable areas without great difficulty, and it is natural that the removal of this difficulty should be receiving consideration.
Fundamental Principles
The object of the present article is to review the difficulties to be met in the problem of providing some adequate degree of secrecy while at the same time preserving the requirements of efficient radio communication, and to indicate the lines along which a solution seems likely to be found. It may be stated that little or nothing has been published on the matter, and the only source of information is the study of patent literature.
Obviously, with line telephony the area over which the speech can be picked up is limited to the region near the wire or cable conveying the current, and systematic eaves- dropping is only possible to persons having access to the wire in question.
The case of a radio station is different. If the signals are capable of being received at one station they can, with suitably designed apparatus, be received at another station.
The only way in which radio communication could approach line communication, with regard to the area over which interception is possible, would he to concentrate the wireless waves into an extremely narrow beam. Now it has been suggested by writers in the non-technical press that the Marconi beam stations radiate in a manner approximating to a beam of this nature. This is certainly not the case. A study of the published data of the beamstations shows that the radiation is directed not in a narrow band, but in a fan several degrees wide. The result is that at a distance of, say, 2,000 to 3,000 miles the radiation can be picked up over an ever-widening belt of not less than two or three hundred miles wide.
In giving this value to the width of the belt it is assumed that the cut off at the edges of the fan is sharp. No reliable evidence is available on this point, but it is extremely likely that the edges of the fan are not sharp, so that the area over which the energy can be received with sufficiently sensitive appara tus is greater still.
It has also been suggested in the non-technical press that the reflector or directive aerial systems employed at the beam receiving stations are essential for the reception of the radiation from the corresponding transmitting station. These reflectors are extremely valuable, in that they make the receiver more sensitive to radiation from a particular direction, and by so doing reduce interference both by atmospherics and by signals from transmitting stations arriving in directions other than that in which it is desired to receive.
It is not true, however, that without the reflectors the signals are so weak that they cannot be picked up with suitable apparatus having a high factor of amplification. The long-distance communication obtained by amateurs employing extremely small powers affords good evidence on this point.
The importance of the reflector aerial lies in the fact that the ratio of signal strength to atmospheric noise is increased, and thereby the number of hours possible per day for satisfactory working is increased. Hence, without a complicated aerial system which could not be erected surreptitiously, reception at long distances from a short-wave beam station would be possible only under comparatively favourable atmospheric conditions, and without the reflector there would be periods at which eavesdropping would be extremely difficult or impossible.
Except in this sense, however, it can be said that present-day beam transmission would be unlikely to provide any adequate degree of secrecy.
Silent Zones
The use of short waves, however, has one advantage which must not be overlooked, namely, the fact that on short waves the energy is radiated for a considerable distance by waves travelling through the upper layer of the earth's atmosphere, while any energy travelling along the ground is absorbed at a comparatively short distance from the transmitter.
[comment. Alas a false assumption. The radio signal may bounce up and down several times rather than travel around the ionosphere - and the signal is subject to scatter]
Apart from a short distance round the transmitting station, therefore, there is a zone of silence of perhaps several hundred miles the exact radius depending on the wavelength used. After this distance the waves deviated from the upper atmosphere reach the earth and signals become comparatively strong. In certain particular cases the existence of the silent zone could no doubt be used to assist in providing a service which could not be intercepted.
On the other hand, the beam system is proving successful in the main for telegraphic communication; and it appears to be generally accepted that the variations in signal strength and fading effects due to the influence of the upper atmosphere on the propagation of short wireless waves render it still desirable that long waves and comparatively high power should he employed in such a service as radiotelephony over long distances where it may be essential for two suhscribers to be put into communication at a prearranged time without delay.
[comment- there is very little room in the truly long waves that are capable of long distances. Medium waves may sometimes travel great distances but not at all reliably. Within limitations, shortwaves were required for long distance communications.]
Since there can he no possibility of guiding longwaves in a beam, the problem of securing secrecy resolves itself into transmitting the speech in such a way that reception becomes difficult without very complicated apparatus!
In using radiotelephony on long waves, one matter which has to be considered is the amount of interference produced on other communications. So great is the amount of signalling by wireless now taking place that the task of fitting in of new lines of communication on long waves presents the greatest difficulty. One of the most important criteria by which a method of radio communication has to be judged is therefore whether it could he introduced into the existing crowded condition of the ether. As will he seen later, many of the suggested secret systems proposed can stand no chance of general adoption on account of their failure to conform to this important condition.
Width of Sidebands
It may therefore be desirable here to consider briefly the causes of the greater interference of radiotelephony services compared with radiotelegraphic services, and to indicate why the system developed by the Western Electric Co. and the British Post Office for transatlantic working has alone made telephony on longwaves a practicle proposition.
The essentials of an ordinary telephony transmitter are the production of a pure and steady continuous wave oscillation and the means of modulating this wave by the audio-frequency vibrations due to the sounds it is desired to transmit.
Now, the audio-frequency vibrations corresponding to a sound can be shown to be made up of a large number of waves corresponding to frequencies of between, say, 200 to 2,200 cycles in the case of speech and perhaps 100 to 10,000 cycles in the case of music.
[comment: Today we look to a telephone to cover frequencies up to 4,000 cycles, whilst music constrained to 10,000 cycles sounds very poor. A music CD - which has a deliberately reduced quality by design- allows sounds up to 22,000 cycles which is normally adequate, although some hi-fi buffs with sharp ears prefer 24,000 cycles or higher.]
The result of modulating the carrier by a complicated speech form is the same as modulating the carrier wave simultaneously with a number of simple component waves into which the ordinary speech can be resolved.
The carrier wave frequency has no effect on the transmission of the sound. In the Western Electric Co.'s system a considerable saving of power is effected by not transmitting the carrier wave at all, but by suppressing it along with one of the side-band frequencies at the transmitting end, and in reintroducing the necessary frequency needed for heterodyning the remaining side-band by means of a weak local oscillator at the receiver.
Not only is there a saving of power of about 75 per cent. in transmitting only one side-band, there is a great reduction of the amount of interference.
If both the side-bands are transmitted, frequency bands of between 200 and 2,200 cycles are present on both sides of the carrier-wave frequency; thus a band about 4,000 cycles wide is taken up by the transmission.
[comment: from the prior comment you may now see why medium wave broadcast stations have transmitter frequencies either 9 or 10,000 cycles apart where the upper frequency of the sound is 4,500 or 5,000 cycles.].
If we put the shortest wave suitable for long-distance communication at, say, 4,000 metres, ie, 75,000 cycles, and the longest at 25,000 metres or 12,000 cycles, the whole number of cycles available for such communication is 60,000, and it is clear that the maximum possible number of radiotelephony services which can be got in between these wavelengths without direct overlapping is only fifteen.
[comment: The author is limiting himself here to long distance communication by ground wave, using very long wavelengths. Short wave radio is often considered to be effective from about 13 metres to 75 metres and there is room for a lot more telephony. This is why short wave was used quite early on...].
Even then no allowance has been made for the various telegraph services taking place on long waves. The number of cycles occupied by a telegraph service is only at few hundred cycles.
Comparing this with the 4,000 cycles required for telephony, it is clear that any proposal for starting telephony services must have a difficult passage with the authorities responsible for the international allocation of wavelengths.
Obviously the chance of fitting in such a service is increased in the case of a system such as the present Western Electric system, where the band taken is only about 2,000 cycles, i.e half of that required by other systems.
The Western Electric side-band system as at present used is secret only so far as speech cannot be received on a simple broadcasting receiver, and cannot, therefore, be inadvertently overheard. The Western Electric Company have, however, covered by patents several schemes for making interception extremely difficult, if not impossible, and the principles of these will be described in due course.
Before dealing with the Western Electric methods, however, it may be of interest to review briefly some other suggestions that have been made. One of the most ingenious was patented by a Danish engineer named Tigerstedt in 1918. His method is applicable both to line telephony or telegraphy and to wireless, and he proposes to provide secrecy by splitting up the Morse signs or words to be transmitted into sections which are rearranged in different order so as to produce an unintelligible jumble which is transmitted into the ether. At the receiving end the components of the speech are automatically rearranged in the proper order so that speech becomes intelligible.
The method uses a rotating metal band and several rotating discs with conductive / insulating segments.
The method depends on the velocity of the moving band and the discs being adjusted so as to be identical in the transmitter and receiver, and suitable methods must be provided for synchronising and correctly adjusting the position of the discs and their segments with regard to one another.
The accurate synchronisation required would probably be difficult to achieve and maintain in practice. It might be possible, however, for a determined eavesdropper to write down or record the sounds heard and piece them together correctly when the conversation interesting him was completed.
If the mechanical difficulties could be overcome this latter objection could be got over by cutting the speech up into more sections.
A considerable number of methods proposed for secret telephony depend on the variation of the length of the carrier wave. One of the simplest methods suggested is to transmit alternately on two wavelengths. The aerial is coupled to two identical generators of continuous waves which are modulated in turn by the same microphone circuit. The exchange between the transmitters is obtained by a rotating mechanical switch. This is so arranged in one device that transmission begins on one wave- length before it has ceased on the other; any interruption of the radiation during the change over is avoided.
The receiving apparatus consists of two detecting circuits connected to the same audio-frequency amplifier leading to the receiving telephones. The receiving circuits are only complicated by the double reception necessary, and apart from the inconvenience of this the method described does not appear to give real degree of secrecy. On the other hand, the occupation of two carrier waves in the ether for the same communication would for the reasons already stated probably render the practical development of the system impossible.
Other systems vary the wavelength of the carrier by regular or irregular variation of the tuning arrangements of the transmitting circuits. The means which have been suggested include the use of condensers with irregular- shaped plates which are caused to rotate mechanically, or the movement of the moving coil of a variometer.
It has also been suggested that the transmitting inductance should be designed on the principle of a concertina, so that by mechanical means the coils of the inductance could be brought close together or separated, and its self - inductance thereby varied.
In receiving the signals the receiving apparatus must be fitted with similarly variable condensers or inductances the moving parts of which are synchronised with the transmitting instruments.
In one method a motor running at constant speed rotates, by means of suitable gears, an irregularly shaped cam which, by an anti-friction roller and a lever imparts movements to the moving coil of a variometer.. A similar variometer is provided at both transmitting and receiving stations. At the receiving station an auxiliary detecting circuit is provided in which is included a relay. The action of the relay causes the movable core of a solenoid to be raised. The upward movement is controlled by a dashpot so as to occupy a prearranged time.
When starting a communication the variometers at the transmitting and receiving stations are set at the same point on their scales and an auxiliary signal from the transmitting set consisting of a long dash is sent out. At agreed times cams of various shapes can be substituted to make the wavelength changes more irregular.
Other Variable Wavelength Schemes
In another method proposed it is suggested that the variation of wavelength of transmitter and receiver be carried out by the motion of synchronised pendulums and an arrangement is provided for stopping the pendulums by wireless means at any selected instant so that a signal can he transmitted on a chosen wavelength which would be unknown to the intercepting station. In any of these methods, however, the band of wavelengths necessary would be so large as to make the method impracticable for actual communication, while if a smaller band were used the signals could he easily picked up on a flatly tuned receiver.
THE practical difficulties referred to above are absent in the methods for secret telephony covered by the series of patents held by the Western Electric Co. (Standard Telephones and Cables, Ltd.).
The arrangements proposed are based on the principle of side-band telephony already in use in the transatlantic service. As already stated, in this system this, main carrier wave is suppressed and only one side band is transmitted.
This system is secret to the extent that no intelligible speech can be received unless incoming waves are heterodyned with local oscillations of correct frequency. Nothing, for example, could be picked up by an ordinary broadcast receiver.
To get over this difficulty the voice band is divided into three or four portions, the frequencies in one or more of which are inverted as desired.
Filters divide the audio into bands and then some are inverted, so that with a band from 200 to 800 cycles, a sound of frequency 200 comes out having a frequency 800, while a highnote of 800 cycles comes out as a low note of 200 cycles.
By employing the same principle a still greater degree of secrecy can be provided. If the speech frequency band is divided into, say, four parts, any one portion of the speech frequencies can be shifted into any other part of the speech band by introducing the correct frequency into a balanced modulator and using a suitable filter.
With a system in which the speech band is divided in four parts it can be shown that 125 combinations of the four portions or sub-bands of the speech are possible which are incapable of yielding more than one of the sub-bands in its normal form in a simple heterodyne receiver, the others being present as unintelligable noise.
It would be possible to change from one combination to another simply by switching arrangements. The changes would be capable of being introduced rapidly at pre-arranged intervals, and thereby a very high degree of secrecy could be provided. The number of possible combinations is worked out in detail in British Patent Specification 219,987, while the principle of the system is more fully described in British Patent Specification 218,282.
It appears to the writer that the development of such methods of inversion of portions of the speech band before transmission on the lines described in these patents is most likely among the methods with which he is acquainted to lead to a satisfactory solution of the problem.
THE recommendation has been put forward by the B.B.C. that frequency in kilocycles instead of wavelength in metres shall be adopted as the numerical indication of station tuning. Thus it is hoped that we shall no longer refer to the Wavelength of the Daventry station as being 1,600 metres but instead that the frequency is 187 kilocycles.
The product of wavelength and frequency is the velocity of the ether wave and is a constant (300,000,000 metres a second), so that frequency is obtained by dividing 300,000,000 by the wavelength.
Until the proposal meets with more general support wavelength is to be given by the B.B.C. as well as frequency, though, so far as the listener is concerned, both wavelength and frequency are not required in determining dial settings in the process of tuning, and it is probably hoped that sooner or later wavelength will cease to survive.
Why is this change to kilocycles required, and what are the advantages to be gained? It must be borne in mind the station wavelengths are allotted not according to wavelength differences in metres, but on a basis of differences in frequencies. To prevent interference by heterodyning, the separation of 10 kilocycles between broadcasting stations has been agreed upon.
Thus from a list of station frequencies rather than wavelengths it can be seen at a glance where spaces exist for the working of new stations. A tuned circuit of good design covers a wavelength range from just below 200 metres to nearly 550 metres, representing a frequency band of 800 k.c., and giving a separation of 2 degrees between stations on the tuning dial.
So far as the listener is concerned, the adoption of kilocycles would prove less tax on the memory than a scale of wavelengths in metres.
For instance, the wavelengths of several of the British stations are represented as 491.8, 384.6, 361.4, 353 and so on. Expressed in kilocycles these become 610, 780, 830, 850, numbers which are easily visualised.
The process of allocation avoids the use of decimals, and the 10 kilocycles separation assures a nought as the last digit.
It is by reference to station frequency that superhetero- dyhe receivers are operated, while a better understanding of the principles of modulation would result by a more general acquaintance with radio frequencies in their relationship with audio frequencies.
On the other hand, assuming a development in short-wave broadcasting, the numerical representing frequency is less convenient than the expression of wavelength in metres. Three wavelengths in use to-day for short-wave broadcasting are 22.02, 30.2 and 32.79 metres, which, expressed in kilocycles, become 13,620, 9,926 and 9,150 (or in kHz, 13.62, 9.926, 8.15)
In regard to short-wave.transmission also there is the direct relationship between the length of an aerial and its fundamental wavelength, and the actual wavelength in metres, therefore, conveys a number which is of real value in the setting up of a station.
For short-wave transmission and reception wavelengths, therefore, will probably continue to be used in preference to frequencies, and the adoption of the frequency scale for the broadcasting band will result in the use of two forms of tuning unit.
Standing in the way of the adoption of a scale of kilocycles is the natural prejudice which exists towards abandoning a system with which we are familiar for one embodying a range of figures which for a while will convey little as to relative magnitude. To think in terms of a new unit will present difficulty, and in so far as the experimenter is concerned frequent reference will need to be made to a kilocycle-metre conversion table.
Receiving sets and wavemeters which are calibrated in terms of Wavelength will require new scales of frequency, though it must not be thought that the utility of tuning condensers following definite straight line laws will be-come obsolete. Correspondence is invited on this subject, and an expression of views may serve to guide those with whom the responsibility rests for recommending the change.
[modern notes-
In the UK radio wavelengths have always been metric, never using imperial measurements- (Radio 5 on 472 yards...). The first popular use of the metric system in the UK?
Today with digital receivers we key in the frequency, which for ease of international use is now in the unit Hertz or Hz where 100 Hz is 100 cycles per second.
In the mid 1960's, the medium wave stations used rounded wavelengths to give a catchy "Caroline on 199" whilst shortwave stations became for example "On 7.10 megacycles in the 41 metre band" - a nice mixture. The 10,000 cycle (10 kHz) separation between stations remains in American medium wave broadcasts but in Europe a narrower gap of 9 kHz is used, so in Europe few frequencies have nice round numbers (Radio 5 on 693...).
The narrower gap between stations causes in theory a lower quality of audio, or if the stations cheat and broadcast wider audio frequencies, more interference between stations. On shortwave stations normally use frquencies ending in 0 or 5 kHz although there are odd exceptions. Use of short-wave broadcasting is diminishing with the rise of digital and internet radio.
]
IN a recent issue of The Times, Capt. Eckersley has stated the case for the B.B.C. on the subject of Empire Broadcasting, and even at the risk of appearing to overburden our readers with our views on this important topic we feel that it would be unfair to those who have so strongly supported our campaign for the establishment of an Empire broadcasting station to allow Capt. Eckersley's discouraging letter to pass without comment.
The burden of Capt. Eckersley's argument is that because what he terms an adequate and satisfactory service throughout the Empire cannot at present be granted we should wait until success is assured before establishing a station.
In this view we heartily disagree with him. In our opinion there is much to be done experimentally on the receiving side in distant parts of the Empire if the short-wave station here is to be picked up satisfactorily enough for rebroadcasting through local transmitters, and how can it be hoped that success will attend these efforts unless considerable time is allowed for reception tests with transmissions from this country available as the subject-matter for the experiments?
Capt. Eckersley adopts a policy of "waiting for perfection" and intimates that the B.B.C., jointly with the Marconi Company and the Radio Corporation of America, hope to achieve something in the future which will give us an Empire service. But why wait until a state approaching perfection is reached? We may never reach that stage, and as far as we can see, for years to come, there will be continual change necessary in improving what to-day we may consider the last word.
If Capt. Eckersley feels so strongly that Empire broadcasting must not be developed by stages, but, instead that he can launch the finished product all at once, we believe that he is making a serious mistake and, further, it appears that to be consistent he ought never to have been satisfied for our own broadcasting to start with small beginnings, but rather he would have had us wait, perhaps, for the regional scheme and alternative programmes, with the present standard of quality in transmission, to be developed silently before any broadcasts took place in this country.
We must remember that broadcasting here started with the experimental transmissions from Writtle, and even after the British Broadcasting Company was formed the transmissions, when viewed from the standard which has been reached to-day, were long in an experimental stage undergoing a process of evolution both on the transmitting and receiving side.
(Captain Peter Eckersley was the first Chief Engineer of the British Broadcasting Company Limited from 1922 to 1927 and Chief Engineer of the British Broadcasting Corporation until 1929. He left under a cloud having failed to meet Reith's moral standards. He chaired the London Central Committee of Oswald Mosley's New Party. He was later involved with MI6 - whilst his second wife, now in Germany, recruited William Joyce to the German cause - she was sentenced to 12 months for assisting the enemy. He died in 1963)
I had already built a short-wave set with which I received the reports of the Dempsey-Sharkey fight. You will see by the front page from the local paper the interest that was taken in my reception of the report of that fight.
[The journal "O Estado do Para" devotes half its front page to an account of this incident, and reproduces a photograph of a group taken at Mr. Foster Smith's residence during the reception of the fight.]
There are only about four of us in this town of some 200,000 inhabitants with receiving sets that give results. Had it been the report of a football match in England the interest would have been greater still, the Brazilians being very keen followers of the game.
Unfortunately most people here seem to think North America is the only country that knows much about wireless, so that it is impossible to buy anything but American parts, and I certainly think that North America owes a lot of its increasing influence in the South American countries to its wireless propaganda, especially on short waves.
Announcements are very often made in Spanish, and advertisements are sometimes made, but not in a way to interfere with the programme. I am quite sure that if England put up a really good abd powerful short-wave station our prestige would go up enormously in South America, and apart from giving a tremendous amount of pleasure to Englishmen in these out-of-the-way spots, it would, no doubt, open up a market for English apparatus. People at home have no idea of the thrill it gives one in a foreign country so far away to hear English songs and music come in over the wireless, even if it is spoken with an American accent or by gramophone records from Holland.
I certainly congratulate you in your efforts to get a short-wave station established, and I sincerely hope that it will not be long before your efforts meet with success, and a really good and powerful short-wave station is established in England.
H Foster Smith. A.M.I.E.E. Para, N Brazil, August 22nd 1927.
Broadcasting's Most Urgent Need - Wider frequency separation needed
Wider Frequency Separation
A STAGE in the design of receivers for broadcast reception has been reached where further progress is no longer possible until changes are made in the system of broadcast distribution. Receivers are available capable of extremely high quality of reproduction, but, except under unusual and most favourable conditions, the full advantages of their capabilities cannot be realised, owing to the narrow frequency band transmitted or the proximity of other transmitting stations.
The frequency range transmitted by the best stations of the B.B.C. is at least equal to that of any transmitters elsewhere in Europe, or, indeed, in the world. Really good reproduction, to be satisfying, should cover a range of about 30-13,000 cycles, but the B,B.C. is far behind this. Unless we are favourably situated near a B.B.C. station, we cannot even enjoy the range at present transmitted without the risk of adjacent-channel interference. It is certainly no use, under present conditions, for the B.B.C. to try to improve much upon their present quality.
The remedy is obvious. It will be necessary, before any real progress can be made and before present technique of receiver design can be utilised to advantage, for the frequency band to be widened at the cost of eliminating a number of stations.
But, unfortunately, all countries in Europe do not at present agree on the question of quality and prefer to compromise. They are content to transmit 21 much narrower band of frequencies than is required, even for passable quality. This being so, it ought surely to be possible to devise a scheme for wavelength distribution where those countries desiring to improve the quality of their transmissions could do so without being penalised by the attitude of less progressive nations. If all countries could agree to the necessity for a wider transmission band for each station, the problem would be solved, but since this seems to be an unattainable goal at present we must look elsewhere for a solution of the problem.
The Solution ?
We are thrown back, then, on to a suggestion which has been put forward in The Wireless World from time to time, that instead of distributing wavelengths amongst the various countries on the present lines so that stations of different nationality jostle one another in all too intimate contact, each country should be allotted a definite band or bands of wavelengths exclusively for their own use. This would mean that, having gained possession of these wavelengths, each country could please itself as to whether the bands were crammed with a large number of stations transmitting poor quality or a limited number putting out the highest quality possible.
Designers and manufacturers of broadcast receivers are marking time; they have the knowledge available to produce sets capable of extremely high quality reproduction, but they are at present deterred from doing so because, under existing conditions, the general public would not be able to take advantage of their possibilities.
Quite definitely the next step towards improving the standard of reception must come from those responsible for wavelength distribution, and some radical change is already overdue.
[Medium wave quality did not change. It was many years before VHF radio broadcasting improved broadcast music quality. Then came digital radio and audio quality plummeted again with many stations using a streaming rate of just 64kbps mono. Really high quality music needs 168 or 192 kbps stereo. Today from all my DAB stations, only the BBC classical music station Radio 3 is streaming at 192kbps stereo. Classic FM is down to 128kbps stereo]
5th April 1935 - Unbiased by Free Grid
Liberty of the Subject
THINGS are coming to a pretty pass in this once glorious country when confidence men and thugs go free while ordinary honest citizens like myself are molested and interfered with by the police.
I was recently taking a stroll through the West End of London in the small hours of the morning in order to get a breath of fresh air after a strenuous day in the laboratory. In my hurry to get out into the open I did not bother to don appropriate dress but sallied forth in my laboratory gear.
I was recently taking a stroll through the VVest End of London in the small hours of the morning in order to get a breath of fresh air after a strenuous day in the laboratory. In my hurry to get out into the open I did not bother to don appropriate dress but sallied forth in my laboratory gear.
Suddenly I recollected an important experimental broadcast which was to be given by the B.B.C. for the benefit of the Nottingham transport depot. Glancing at my watch I saw that, even if I raced home at top speed, I should not be in time for the concert, so it occurred to me to knock up one of the residents of Fashionable Square with a request to be allowed to use the wireless set. And then a brilliant idea struck me. All round were serried ranks of parked cars, the owners of which were evidently disporting themselves in one of the numerous night clubs which infest these parts.
I was not long in locating a car fitted with radio. Slipping inside I soon had the programme tuned in and was at once carried away by the lilt of a Viennese waltz. Almost immediately an enquiring Constabulary head was thrust in the window with a coarse command to "Come on aht of it." I raised my hand to enjoin silence- but was roughly bundled out on to the pavement and marched off to the station, where the sergeant-in-charge, after listening in stony silence to my explanation, advised me in an exceedingly unmannerly way to "Try and think of a better one to tell his nibs in the morning."
Although my explanation was accepted next morning I could not help feeling that I had, to say the least of it, suffered loss of dignity. Incidentally, while the constable was engaged in his altercation with me in the car a successful burglary was, I found out later, perpetrated in the vicinity.
30 m.p.h.
INVENTORS are, I see, already busy with schemes to assist motorists to avoid unwittingly exceeding the new thirty-miles-per-hour speed limit. Various ideas have been suggested, such as lighting a warning signal on the dashboard or blowing an electric horn when the speed limit is reached.
One of the most novel schemes, however, is the coupling of the speedometer to the car radio set by a special switch so that the music is cut off when the car attains a speed of thirty miles an hour. Although certainly novel and ingenious, the idea is at fault, insomuch that it presupposes that every car is fitted with a set. Possibly the inventor is a radio manufacturer in disguise
The scheme also presupposes that each set will normally be in use and so be in a position to be automatically turned off, but this is not an essential point, for the switch could be arranged so that the set was turned on if it happened not to be in use at the time or turned off if it were actually in operation.
The idea rather reminds me of the old American device in the early days of motoring when relatively high speeds in primitive cars were a real danger to the motorist. When the car attained a certain pre-determined speed a concealed gramophone was turned on, the record being Chopin's Funeral March or some even more appropriate tune.
Jubilee Week
THIS week of Silver Jubilee celebrations will provide a memorable and inspiring climax to the splendid economic and social achievements standing to the credit of Great Britain after anxious periods magnificently surmounted. Had thc same set of circumstances occurred some twenty or even fewer years ago the nation would have been thrilled. But the complete absorption of the whole of the people into one united family surrounding the Throne would not have been possible then, in the absence of broadcasting, as it is to-day.
To-day thanks to the universal use of wireless, and thanks also to the British Broadcasting Corporation for having established not only a complete broadcasting service tluoughout the mother country, but also a short-wave broadcast distribution, the whole Empire is simultaneously informed of all that is happening this week in the heart of the British commonwealth of nations.
No matter where Britons may be found, Buckingham Palace, St. Pau1's and the great thoroughfares of the Metropolis will bc brought before them by the agency of broadcasting. Throughout the far-flung Empire, in the very remotest parts of the earth, the subjects of the King will be able to take an intimate part in the Pageant of the Silver Jubilee as it unfolds itself before those who can be actual eye-witnesses of it.
Nothing could provide a more striking demonstration than this of the value of an invention, that it should have done so much to weld the British peoples into one closely knit family.
His Majesty, whose twenty-five years of beneficent sovereignty we acclaim this week, is himself a broadcaster. By means of wireless King George's voice has reached the ears of millions of his subjects, and it is but bare truth to say that no broadcast is ever awaited with such eagerness and expectancy as His Majesty's annual greeting to his peoples on Christmas Day.
May he long be spared to repeat again and again that heartening bond made possible by wireless between the Royal House and the homes of his subjects.
Programmes
JUST as Jubilee Week is an outstanding event in the lives of every one of us so is it a week of great undertakings and responsibility for the B.B.C, The task which the Corporation has set itself to do in order to enable this country, the Empire, and the world to participate in these celebrations will exact a high degree of efficiency even from so well organised a system already accustomed to big achievements in broadcasting topical events. The Outside Broadcast Department of the B.B.C. in London will have one of the busiest weeks on record. No less than eighty-four microphones will be in use and eighteen control units. The B.B.C. estimates that 5,200 yards of cable will be used for connecting up the microphones and there will be a thousand terminal connections to make.
FUTURE OF CAR RADIO
Effect of Ministry's Announcement
A STATEMENT recently issued by the Ministry of Transport to the effect that no ban is to be placed on the use of radio sets in motor cars has apparently reassured many motorists who have hitherto hesitated to install receivers. According to Ekco, orders for their car sets have increased by over 150 per cent. since the statement was issued.
Special arrangements are being made to train engineers in the fitting of these sets, and E. K. Cole, Ltd., are planning for double their normal installation facilities throughout the present summer.
It is expected, too, that British car radio will find a ready market on the Continent.
[ Ekco started in the wireless business in 1924, then their interest in bakelite radio cabinets led on to plastic, including the first refridgerator plastic lining. Ekco bought radio brands Dynatron in 1954 and Ferranti in 1957, later merging with Pye in 1960. The Pye merger was unwise and led to a collapse of Ekco - the various brand names changed hands several times thereafter.]
THE passion which some people have for labour-saving devices is truly extraordinary, and nothing more strikingly illustrates this than a new economy scheme adopted by certain continental cinema proprietors whereby wireless is used in an entirely novel manner to take the place of highly paid organists.
This scheme does not, as you might be tempted to think, involve the electrical reproduction of canned music, but is some- thing quite different.
It appears that in continental cinemas -the same pernicious habit is followed as over here, of picking out the organ manual in coloured floodlights during the orgy of sugary sob-stuff which is dignified by the name of music and is churned out during the so-called organ interlude.
Actually there is an organ in only one cinema of a given town, and this organ manual is electrically coupled to those of all the other cinemas in the town. This coupling was at first accomplished by cable, but now apparently all go-ahead firms are using short-wave wireless as the connecting link.
The programmes are arranged, of course, so that the organ interludes occur at the same time in all "controlled" theatres, In this manner the four-figure salaries of several cinema organists are saved. The patrons of the subsidiary theatres are not, of course, aware of this subterfuge, as ingenious dummies - life sized marionettes, in fact - are employed. What the eye doesn't perceive the heart doesn't grieve over, as the doctor said when he mixed up the babies in the clinic.
(June 1935)
The Post Office also grants licences to commercial companies for the establishment of wireless services from point to point. [cut explanation of experimental uses special terms].
Since the date of the Wireless Telegraph Act, possible applications of wireless for communications purposes have been very greatly extended, and on ultra-short waves in particular a very valuable and convenient means of communication has been developed.
Whilst recognising that these wavelengths are likely to be in great demand for a multitude of important purposes, it nevertheless seems desirable that some opportunity should be given for the establishment of private stations for point to point communication.
A new industry could be built up from the sale of compact telephony receivers and transmitters suitable for the equipment of trains, buses and cars requiring to communicate with other points...
For general use transmitters and receivers could be supplied pre-tuned to fixed wavelengths to ensure that they were not used to intercept transmissions not intended for them.
An adequate charge for a licence would of course be made by the PMG with such regulations as were considered necessary.
EDITORIAL COMMENT- Empire Wireless
British Programmes on Foreign Sets
THE radio manufacturer in this country, with certain rare exceptions, is so engrossed in the problems of supplying the home market that he neglects, and in most cases totally ignores, the overseas and Empire requirements. Although these markets are still open to him, with the present rate of foreign competition and absence of British enterprise they may not long remain so.
From information which has come to us from different parts of the Empire there is evidence that, whereas a year or two ago sets of British manufacture would have been welcome and bought in preference to all other makes, that attitude scarcely holds to-day because American and other suppliers have been so enterprising that the suitability of their products, added to the service which goes with them, loads the scales far too heavily, even when a large amount of pro-British inclination is added in favour of the British set.
All-wave Sets
For more than a year the sets exported from Germany, United States, and some other countries have been almost exclusively all-wave receivers which include the short-wave bands. Here such sets have only recently made their appearance, and even now comparatively few manufacturers have produced them. Coupled with this must be added evidence that service depots, where real service can be given and spare parts kept in stock, must be established locally at the time exporting is begun, so that customers have some assurance that their receivers can be cared for after purchase. But the British exporter is either indifferent to any service troubles which may arise after purchase or assumes that there will be none. Our correspondence indicates it is for this reason that in far too many localities overseas the popularity of British sets is not being maintained where foreign competition has stepped in.
Customers are Waiting to Know
There are hundreds of thousands of prospective purchasers of British receivers overseas who are anxious to know what is the attitude of manufacturers at home. Are they prepared to supply all-wave receivers which will compete in performance with the products of foreign rivals and to organise adequate service arrangements?
To export half-heartedly apparatus which is not competitive in performance and without proper service arrangements is not only dangerous to our trade prestige as a whole but is the surest way of giving competitors further advantages.
Our manufacturers are capable of supplying what is needed, and if once they show themselves willing and determined to meet the demand they will find ready co-operation in every part of the Empire, since a preference for our manufactures still remains strong, and natural ties give the home manufacturer an asset which his foreign rivals cannot compete against. But the whole matter is urgent, because delay is only making the task of competing harder. It is a case, too, for co-operation between British manufacturers to eliminate competition between themselves in any area. Agreement on these lines would not only assist the manufacturer to meet foreign competition more firmly, but would have the additional advantage of simplifying service and the supply of valves and spares for one type of receiver instead of a variety of types.
FREQUENCY MODULATION : Success of Triple Relay Experiment
HAVING heard a demonstation programme that had been relayed three times by frequency-modulation stations,Mr. K. B. Warner, managing secretary of the American Radio Relay League, and editor of QST, said :I thought it was just technically unbelievable with three relays, yet the programme was still better by far than the present conventional system at its best. In ten years there won't be any orthodox brand of bwadcasting remaining except for the lowest grade of local service.
The demonstration programme, which included sounds requiring a high degree of fidelity to reproduce them, was broadcast by W2XCR at Yonkers, New York. It was received and rebroadcast by Major Armstrong's station W2XMN at Alpine, New ]ersey. The transmission from W2XMN was received at Meriden, Conn., and again broadcast by W1XPW, which transmission was received in the studio of WDRC, Hartford, Conn., before those invited to hear the demonstration.
It was in order to prove the practicability of a chain of F-M stations that the demonstration was staged, for it is not possible to use cable links between F-M stations as they will not transmit a 15 kc/s band.
About 25 frequency- modulation transmitters, it is stated, will be in use by midsummer.
OF late years, largely owing to the work of Major Armstrong, radio engineers have been coming more and more round to the point of view that where high quality and freedom from interference is of paramount importance, frequency modulation shows a marked superiority over the conventional amplitude modulation system.
General Conclusions
(1) The design, construction and operation of a frequency modulated transmitter need be no more complicated nor markedly different as to details from that of an amplitude modulated transmitter.
(2) The frequency modulated transmitter can be smaller, lighter and more economical of power than the amplitude transmitter of the same power rating.
(3) The frequency modulation receiver need be no greater in size or weight than the conventional amplitude modulation type.
(4) A given area can be satisfactorily served by means of frequency modulation with considerably less power than by means of amplitude modulation.
(5) A given transmitter power will provide service to a markedly larger area, or with a markedly lower noise level when employing frequency modulation than when employing amplitude modulation.
(6) Simultaneous operation of frequency modulated transmitters on the same frequency with a given degree of inter-station interference, can be carried on with relatively minute geographical separation between transmitters as compared with that required for the similar operation of amplitude modulated transmitters.
(7) The number of frequency modulated transmitters that might be simultaneously operated within any large area on a given number of frequency modulation channels, and with given permissible interference areas, is so great compared with the number of amplitude modulated transmitters, that might be so operated, as to more than compensate for the width of the frequency band required to take substantial advantage of the superiority of frequency modulation.
All ordinary receiving licences for road vehicles were cancelled on May 31st, when it was announced that all apparatus (including aerials) installed in motor cars or other road vehicles had to be removed by June 2nd whether the vehicle was at present in use or laid up.
The licences in respect of these vehicles are to be retained by the owners. Whilst no refund of the licence fee is to be made, the question whether an allowance can be granted in respect of the unexpired period will be considered when the present embargo is lifted.
A similar defence regulation has been in force in France since early this year.
The Postmaster-General states that he is unable to give a general exemption to persons or firms engaged in the supply or conveyance of radio sets to customers or the collection of receivers for repairs. In this connection, no difficulty would appear to arise in regard to mains-operated receivers which could not be used in a vehicle. In the case of battery operated sets, whether "portable" or not, it should be arranged if possible that the battery is carried on another occasion or alternatively is kept separate from the receiver, and is securely wrapped and sealed.
An unmarried private in the R.A.O.C. receives 19s. 3d.(96p) per week, which rapidly rises to GBP 1 13s. 3d. (GBP 1.66)
Application forms may be obtained from The Chief Ordnance Officer, Royal Arsenal, Woolwich, London, S.E.18.
The order required all rnanufacturers of and wholesale dealers in controlled goods to apply to the Board of Trade for registration before June 20th. Under the order manufacturers and wholesalers will be permitted to supply to retailers during the six months to November 30th approximately two-thirds of the value of their pre-war requirements.
THE Radio Corporation of America, in defence of its adoption of the American R.M.A.'s television standard of 441 lines 30 frames, has issued a statement saying that it believes these standards incorporate the best features that have been developed in the United States, England, Germany and the rest of the world.
During the course of a recent F.C.C. investigation, the suggestion was made that television receivers should be manufactured that would be able to receive transmissions from stations operated under other standards as well as under those of the R.M.A.
Whilst being prepared to build such receivers in order to overcome the present deadlock, the R.C.A. does not believe that the adoption of such a suggestion would prove to be of advantage either from an engineering, economic or public service standpoint.
It was learned on enquiry at the G.P.O. that relay apparatus installed in subscribers' houses does not come under this ban because the subscriber has no control over the apparatus.
In the full list of goods that will be subject to the Purchase Tax which was issued on August 1st, Section 12 includes the following, which are chargeable at the basic rate of one-third of the wholesale value: Wireless receiving sets of the domestic or portable type, radio gramophones and valves, batteries and accumulators suitable for use therewith. Gramophone records, with the exception of those for the reproduction of speech, and specially adapted for the use of the blind, are also included in this section.