CTO and BEAM RADIO | ||||||||
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Beam radio was a short wave service that used a huge array of vertical wires supported between 'T' shaped masts. Due to the sharp beam produced by the antenna it required precise alignment during construction to ensure the transmitted signal was directed along the exact bearing of the distant receiving station. The short wave Imperial Wireless Service "beam stations" operated in pairs; one transmitting and one receiving. Pairs of stations were sited at (transmitters first):-
The aerials at Bodmin and Bridgwater stretched nearly half a mile (800m) long, and consisted of a row of five 277 feet (84m) high lattice masts, erected in a line at 640 feet (200m) intervals and at right angles to the overseas receiving station. The masts were topped by a cross-arm measuring 10 feet (3m) high by 90 feet (27m) wide, from which the vertical wires of the aerial were hung, forming a "curtain antenna". At Tetney the antenna for India was similar to those at Bodmin and Bridgwater, while the Australian aerial was carried on three 275 feet (84m) high masts. The Central Telegraph Office (CTO) had direct links to these transmitters and receiver stations. The transmitters were built between 1925 and 1928. Pictures are only available for Tetney and Skegness. An article on the Empire Beam Radio from Radio Broadcast, Volume 10, 1927 How do you send a Telegram to an Empire country The form was marked "Via Imperial" and telegraphed to the Central Telegraph Office (CTO) in London, probably by Morse. At the CTO the message was changed into dots and dashes and punched onto a paper tape. This tape was then fed into the relevant Beam radio transmitting machine which usually operated at 150 words per minute and the the signals were sent along land lines to the sending Beam radio station. At the Beam Radio Station they passed through a valve transmitter to the aerial and then transmitted to their paired country. The aerial is in a fixed position and aimed directly at an Empire country. The signal navigates the earths atmosphere and is collected by a set of aerials and a receiver located in the Empire country. The signals received are then sent by land line to the central post office in the receiving country, who would forward the message onwards to the an adjoining country or a local telegraph office where they are printed, in words and figures, on to a tape, which would be pasted onto a telegram form and then delivered to the recipient.
Bodmin Radio Station Bodmin Radio Station opened in October 1926, following the agreement in July 1924 with Marconi Wireless Telegraph Company Limited to supply high frequency transmitting stations for greater capacity telegraph circuits. Situated at Luxulyan, Cornwall, it was the first HF Beam transmitting station on which work was commenced in the UK. The Bodmin to South African service opened in July 1927, and the Beam service was augmented by the opening of services to India and Australia using the transmitter and receiving stations at Grimsby and Skegness. In September 1929, all telegraph communications of the Commonwealth and Empire were taken over by Cable & Wireless Ltd, and the station operated successfully until the outbreak of war in 1939, when it was closed and completely vacated. The station was leased to the Air Ministry in 1940, and the Royal Air Force installed their own equipment and aerials, operating the station until 1945. In 1947, Cable & Wireless were asked to re-open Bodmin by the Admiralty, installing transmitters provided by them and maintaining services operated from Whitehall to naval ships and bases abroad. A replacement programme for Bodmin was decided upon by the Ministry of Defence in 1969, who agreed to hold the station until 1988. An article from the Evening Post, Volume CV, Issue 59, page 7 (10th March 1923) TWELVE YEARS OF DRIFT
"A Wireless Expert," writing in "The Observer," returns to the evergreen subject of "Wireless and the Empire." "However skillfully the facts may be camouflaged by official apologists," says the writer, "the' public has an uneasy feeling .that the Government has kept wireless telegraphy in its own hands, and has made a mess of it. The broad fact is. indisputable that Great Britain today is almost entirely dependent on the cables for its external telegraphic communications. Such wireless services as at present exist are so limited as, to quote the phrase of a contemporary, 'to leave this country in a position of wireless isolation.' This state of things is an Imperial danger, and a grave trade handicap. At present, owing to the inevitable limitations of cable telegraphy, high rates, delayed, service, and liability to interruption, the different parts of the Empire are ignorant of most of the events of prime importance happening in any part other than its own. "For the British Empire to continue to depend on the cables for telegraphic communication is to invite disaster, perhaps to ensure it." AN EXTRAORDINARY STORY Why are we in our present position of wireless isolation? asks the writer, who continues to relate an extraordinary story: "Twelve years ago Mr. Godfrey Isaacs, on behalf of the Marconi Company, put forward a scheme for linking up the Empire by wireless telegraphy. His company was prepared to undertake the work .and to give the British Empire an Imperial wireless chain within three years of securing permission from the Government. The Government of that day decided that such a project was too important to be left to private enterprise, and that its control and conduct must be in the hands of the Government. That was in 1910. For twelve years the scheme has remained in Government hands. Private enterprise has been forbidden to touch it, and today, after twelve years of inquiry and-report, and experiment and negotiation, and it may be added, a lavish expenditure of the taxpayer's money, the Empire is as far from getting a Government wireless chain as it was twelve years ago."WIRELESS GUARD OF THE PACIFIC "Twelve years ago Great Britain led the world in wireless telegraphy. It was in this country that Mr. Marconi carried on his most important experiments and secured the most far-reaching developments of his revolutionary discovery. But to-day, instead of leading the world in the practice of wireless telegraphy, Great Britain ranks fourth or fifth amongst the great Powers. The United State of America, France, and Germany are certainly far ahead of this country, and the same observation probably applies to Italy and to Japan. Each of the first three-named Powers has constructed and. is working high-power stations, and is conducting a world-wide wireless telegraph service. As Dr., Eccles, the Government expert, truly stated, we have left the United States, France, and Japan to keep wireless guard over the Pacific. France, through its magnificent chain of stations at St. Assise, has now continuous connection with China on one side of the world, and with South American on the other, and Paris has become what London used to be the news centre of Europe. Germany is conducting a world-divide service from Nauen. "What is the explanation of this state of things, which must be galling to every patriotic Briton? It is not to be found in any technical deficiency of British wireless engineers, for the wireless engineers of this country are equal to any in America, France, Germany, or Japan. The one feature which distinguishes the development of wireless telegraphy in this country from its position in the other great Powers of the world is that whilst Great Britain has kept wireless telegraphy under Government control and has steadily refused to allow private enterprise a free hand, the United States of America, France, and Germany, have entrusted commercial wireless telegraphy entirely to private enterprise.'THE IDEAL SYSTEM "Great Britain, each of the Dominions, and India, require improved means of communication not only with each other, but with the whole of the world. To construct wireless telegraph stations for communication with the Empire only is seriously to diminish the available revenue and usefulness of such stations, whilst greatly increasing the overhead charges. "The ideal system would be one in which all the stations in this country, Imperial and foreign, were so constructed as to be interchangeable. There are two strong reasons for this course. One of them is in the nature of telegraph traffic, and the other in the physical conditions under which wireless telegraphy has to work. Telegraphy traffic does not come forward to any one part of the world in a steady flow throughout the whole twenty-four hours. It comes forward in spurt. While certain, hours of the day are very busy, during other hours of the day the demand for communication is limited.. Under a coordinated system of Imperial and foreign wireless telegraphy it would be possible to concentrate all the stations in this country on dealing with the traffic with any one Dominion during the time when work was heaviest, thus avoiding the serious delays which are at present characteristic of the cables.
An article from the Evening Post,
Volume XIII, Issue 3, page 9
(5th January 1927) BEAM WIRELESS - INAUGURATING THE SERVICE EXTRAORDINARY ACHIEVEMENT The wireless stations constructed at Bodmin and Bridgwater for communication with Canada on the Marconi short wave beam principle having passed their official Seven days' test in the General Post Office announced that a high-speed wireless telegraph service between Great Britain and Canada through these stations would be opened on 25th October. With the first Dominion, beam service thus established, Great Britain's world leadership in wireless communication is maintained. As the home, of Senatore Marconi's first long-distance wireless experiments. Great Britain was the pioneer country in commercial wireless telegraphy.
And now, with the modern high-power valve | transmitting station at Rugby
for all round communication, and the Marconi beam stations for direct
communication between the Mother Country and each of the Dominions, it
possesses the most complete, up-to-date, and efficient wireless service of
any country in the world. A FAR-REACHING REVERSAL OF POLICY It was in 1923, after several years of discussion, that the Government definitely decided to proceed with the erection of wireless stations to communicate with each of the Dominions. The Dominions had boon pressing for such a service for some years, and when the British Government's decision was taken they immediately put arrangements in hand for the erection of corresponding stations to form a complete Empire wireless service. While negotiations wore proceeding with the Marconi company for the erection of high power long-wave valve transmitting stations to carry out those services, Senatore Marconi became convinced, as the result of his experiments, that a new system of wireless telegraphy could be developed that would enable these Imperial services to be carried out much more efficiently and at much lower cost than was contemplated by the high-power long-wave wireless stations. His plan was to. use short wireless waves - of 100 metres or less - which, contrary to the generally accepted theory at that time, he had proved to be quite reliable for communicating over great distances; and to increase the strength of signals and the speed and efficiency of working by employing reflectors to concentrate into a narrow beam the wireless energy at the transmitting station and to reflect a greater amount of energy on to the receiving aerial at the receiving Station. As Senatore Marconi has said, a considerable amount of courage was necessary to propose such a revolutionary change. He had no uncertainty, however, neither had the company of which he is the 'chairman;' and the proposal was put before the Government. So convincing were the arguments in favour of the new system that the whole technical policy of Imperial wireless communication was revised and the Government entered into a contract with Marconi's Wireless Telegraph Company Ltd., to build short wave beam wireless stations in England, to communicate with Canada, South Africa, Australia, and India. The Governments and wireless companies in each of these Dominions wore equally impressed with -the value of the beam system and contracted with the Marconi Company to build corresponding stations to communicate with those being erected in England. The building of the stations was started in April, 1925. They have been longer under construction than was at first anticipated, but this has been due to the fact that research work has been carried on simultaneously with constructional work, and many valuable improvements on the original designs have been made as the work progressed. Power valves have had to be specially designed to deal with the extra high frequencies of short wave working, and the Marconi oil-cooled valves at the transmitting station are the most efficient of their kind in the world.
The official Post Office tests laid down that the stations for the Canadian service should be capable of communication at a speed of 500 letters per minute each way (exclusive of any repetitions necessary to ensure accuracy) during a daily average of 18 hours, and that a demonstration fulfilling this condition should be given by actual working for seven consecutive days. This test took place between 7th October and 14th October, and the guarantees - which wore regarded by everyone as being extremely stringent - have been fulfilled. During these and the preliminary tests carried out by the Marconi Company speeds of 1250 letters per minute in each direction, equal to 2500 letters per minute over the complete circuit, have been worked for many hours on end. Counting every hour of the seven days test the average speed of signalling has been about 600 letters per minute in each direction, or 1200 letters per minute for the complete circuit. This result abundantly justifies the claims made for the beam system, and indicates that the stations will be capable of handling all the traffic that is likely to be available between England and Canada for some years to come. Wireless telegraph engineers arc used to high signalling speeds, but the extraordinary achievements of the beam system have been the cause of several surprising and amusing incidents, duo to the speed, of working during the recent tests. On more than one occasion the engineer has put a message on the Canadian circuit, and before he could reach the recording room in the same building he was handed the reply from Canada.
The institution of direct Marconi wireless telegraph services between London and Paris and other Continental centres has shown that new telegraph traffic is created by the provision of new and rapid means of communication. It can therefore be confidently anticipated that the establishment of the beam services, which can be worked at a speed which will enable largo volumes of traffic to be built with in the shortest possible time, will create new business that has not previously been possible, and so bestow a great benefit on the commerce of Great Britain and Canada. In this connection it is interesting to note that Canada has shared with
Great Britain the pioneer position in commercial wireless communication
since Senatore Marconi's earliest long-distance experiments in December,
1901 of which the 25th anniversary will be celebrated this year; and the
establishment of the first trans-Atlantic commercial wireless service
between Clifden, Ireland, and Glace Bay, Canada, in 1907. By being the first
Dominion to open a beam service it continues to take and lead in the
development of this means of communication. The beam transmitting station in
Canada is situated at Drummondville, 30 miles cast of Montreal, and the
receiving station at Yamachiche, 25 miles north of Drummondville. These
stations are linked up by land line to the central office of the Canadian.
Marconi Company in Montreal in the same way that the English stations are
linked to the General Post Office. Beam stations are also being erected in
Canada for direct communication with Australia, and corresponding beam
stations arc being built at Melbourne. COMPLETING THE EMPIRE SCHEME The sites occupied by the beam stations at Bodmin and Bridgwater for communication with Canada are also utilised for the stations to be used for communication with South Africa. These South African stations are practically complete. Similar stations arc being built at Tetney, near Grimsby, and at Winthorpe, near Skegness, for communication with Australia and India - the Grimsby stations being transmitting stations and the Skegness stations receiving stations. Corresponding stations are being built in the Dominions near Capetown, Melbourne and Bombay. All those stations are in an advanced state of construction and are expected to be opened within the next few months. This will complete the present Imperial schemes; but outside this scheme the Marconi Company is already engaged on a considerable development of commercial telegraph services on the beam principle. The company holds a license from the Post Office to conduct wireless telegraph services with certain Continental countries and with all other foreign countries outside Europe. In addition to the wireless stations it has been operating on these services for some years, it has a beam station nearly completed at Dorchester for communication with North and South America. A corresponding station is also in. process of erection at Rio do Janeiro. Another important development in which beam stations are included, and
are already under construction, is the Portuguese scheme for linking up
Portugal and its colonies. Some time ago the Marconi Company obtained a
concession from the Portuguese Government for the establishment of wireless
telegraph stations in Portugal and its colonies for the purpose of linking
them together and establishing wireless communication with other parts of
the world. These stations are how boing built at Lisbon, in the Cape Verde
Islands, the Azores, and in East and West Africa. When they are completed,
wireless services will be established with England and the principal
Continental countries and with South America. The Marconi short-wave beam
stations in this scheme are being erected at Lisbon, Loanda, and Mozambique! ADVANTAGES OP THE BEAM SYSTEM It is claimed that a beam wireless station has the following distinct advantages over any other form of telegraph communications for point to point communication over similar distances. The capital expenditure involved is considerably loss; it is more economical to run and maintain; and it is by far the most speedy method of communication yet devised. The speed of working of the beam system is at present limited only by the mechanical limitations of the transmitting and recording instruments, and when suitable moans of recording over land lines at higher speeds than at present obtainable have been developed it will be possible to increase correspondingly the overall speed of signalling. The results of tests between England and Canada have shown that the use of beam aerials at both transmitting and receiving stations has resulted in a strength of signal some 100 times that obtainable with non-directional transmitting and receiving aerials at each end, and utilising the same power it has enabled the service to be carried on under conditions when signals obtained by utilising non-directional aerials were hardly appreciable. At the same time the use of beam aerials has resulted in a very large degree of freedom from atmospheric disturbance.
The Bodmin station, which is built upon a strip of land bordering the main Bodmin-Truro road, 4.5 miles south-west of the Cornish country town comprises two transmitting systems, one for communication with Canada and the other for communication with South Africa. The receiving stations, are situated near North Potheton, 2.5 miles south of Bridgwater, off the main Bridgwater-Taunton road. The masts and aerial system - the design of' which is peculiar to the shortwave beam system and is entirely different from the design previously used in commercial wireless stations - are similar at both stations. There are five lattice steel masts for each service erected in a straight line and aligned so that the great circle bearing on the distant station is at light angles to the line of masts. The beam is therefore projected, accurately in the direction of the stations with which communication is being maintained. The masts are 277 feet high, with cross-arms at the top, measuring 90 feet from end to end, and giving an additional 10 feet to the height of the mast. The aerial and reflector systems consist of a number of vertical wires, forming as it were a wire curtain, suspended from steel- cables attached to the cross-arms and running along each side of the row of masts. The aerial system is on one side of the masts, facing the distant station, and the reflector system is on the opposite side. The transmitter - which, is, rated at only 20 kilowatts - is of an entirely new design throughout, and is extremely compact Stability of wave length, which is of the greatest importance in short wave work, is obtained by exceptional care in the design of the set. The transmitter is operated direct from the Central Radio Office at the General Post Office in London. The land line is led in to a relay attached to the first panel of the set. By this means the operator in London is in full control of the transmitter, and at the moment he presses his key or feeds his signalling tape into a high-speed telegraph instrument, the signals he is sending are being recorded in the telegraph office in Montreal, which is connected in a similar manner to the Canadian wireless receiving station. In the same way the messages put on to the transmitter in the telegraph office in Montreal are instantly recorded at the General Post Office in London, after having traversed the Atlantic and passed through the beam receiving station at Bridgwater. Now that the Canadian station has been completed satisfactorily, the preliminary tests will at once be proceeded with in the case of communication between England and-South Africa.. On the completion of these tests, those with Australia and India will follow, the construction of beam stations for all these services being nearly completed.
BEAM SERVICES.
HC Deb 22 July 1929 volume 230 c926W 926W
Mr. BOWEN Mr. LEES-SMITH
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