5
494
5. We have given careful consideration to every question submitted to us in our terms of reference. We are officially informed, however, that the Cabinet desires to receive our report at the earliest possible date. To answer definitely and in detail all these questions-that is, to present a scheme of Imperial wireless communication complete alike in technical, commercial, strategic, topographical and financial det would require at least three months' further work, including the appointment of sub-committees to furnish us with exact details upon several aspects of the problem, We have accordingly thought it best to meet the wish of the Cabinet by presenting & report at once in as definitive a form as is possible under the circumstances, leaving to the future the investigation and settlement of certain details, if our views upon the question as a whole should find acceptance.
6. The objects to be served by an Imperial scheme of wireless communication are two: strategic and commercial. Strategic needs are common in a large degree to the Navy, the Army and the Air Force. In many cases the same place will be a naval base, a military headquarters, and a centre of aviation. Such places would often be also commercial centres. Thus strategic and commercial needs will frequently be met by the same station. Where this is not the case, the Navy requires the possibility of quick communication with every naval base in the Empire. Further, the Admiralty desires that the scheme shall afford means of transmitting naval orders to every ship of and above the class of light cruiser, wherever it may be at sea between latitude 60° N. and latitude Go* S. This last requirement, apart from the question of latitude, may be met by arranging for the substitution at any moment of band transmission for automatic transmission in every Imperial main station. Ships will not be equipped to receive high-speed messages, but any ship that can erect an aerial with a spread of 100 feet can, by carrying supplementary receiving apparatus weighing a few pounds and costing a few pounds, receive messages of any wave-length employed in long- distance working. The Admiralty requirement that communication should be possible to any point at sea, either direct or through not more than two linking stations, between the above parallels of latitude will, we think, be generally met by our proposals, with the aid of certain existing stations, and subject to what is said later regarding stations in Australia and Canada.
7. The War Office presented to us a scheme calling for the construction of twenty-two main stations and twenty-three subsidiary stations, the total capital cost. of which would certainly be many millions of pounds. We are of opinion that the chief military and air force needs will be met by the scheme necessary for commercial requirements. And we have adopted the principle that if one of the fighting services should hereafter require subsidiary communication with a locality where little or no commercial need exists or is likely to arise, the station in such locality would be erected and maintained at the cost of the service requiring it. Rare commercial messages passing on such a route might be transmitted by the service operators, to whom they would afford welcome practice in spare time. It would, in our opinion, be unreasonable to handicap a commercial Imperial scheme with the cost of purely military needs of this kind.
8. So far as concefns conditions of working, commercial wireless requirements are so much more exacting than strategic requirements that where these two classes coincide geographically a good commercial service will, with one consideration excepted, more than fulfil every strategic need. The exception is that the stations must be in defended or defensible areas; that is, on land they must be adjacent to areas of established
Service D (Transatlantic)." In nearly all cases each word was repeated twice."
.....often breaks down altogether."
LE
"Both sides send out their messages in a haphazard kind of way, without knowing whether they are being received or not."
"The average speed is about 15 words per minute. Usually each word is sent twice. Several hours each day are spent in giving and receiving repetitions.”
When atmospherics were reported as "light to moderate":-
Of 991 words 679 repeats.
11
1,887
722
"
"
2,296 2,804
994 817
11
ל
In this service during twenty-four days on the European aide the rate of traffic while working at hand speed was, including repetitions, 861 words per minute, and for new traffic only, 2-64 worde. During thirty-four days on the American side the rate, including repetitiona, was 5:13 words per minute, and for new traffic only, 4·18 words.
[3569]
military concentration, and they must not be situated on small islands or be otherwise liable to destructive bombardment from the sea. sudden attack by aircraft all the machinery and apparatus of the main home stations, It is evident that to be secure from except the aerial system, should be placed at some depth underground, but the cost of such security would be prohibitive. They must, however, for obvious reasons, be
situated at some distance inland.
9. In considering commercial requirements, it is necessary at the outset to define what is here meant by a satisfactory commercial wireless service. The three chief factors of this are reliability, speed and cheapness. commercial service depends upon the number of words correctly transmitted and In other words, the quality of a recorded in a given time, and the charge per word. If the service aims at becoming self-supporting, while offering low rates to the public, sufficient paying traffic must ultimately be secured to keep the stations occupied for practically twenty-four hours a day at high speed. This cannot be done unless three conditions are fulfilled. First, the wireless route must be not only quick, but also accurate. In every commercial message
there are necessarily several non-paying service words, and in a State-owned system a number of official non-paying messages must be transmitted every day; but of the remainder a high percentage must be paying words, that is, there must not be a large amount of unremunerative traffic in the shape of requests to repeat, and the repetition of, words incorrectly or only partially received. Second, given a fast and accurate twenty-four hours' service, the charge to the public per word must be low enough to create a large new telegraphic traffic. Third, even a chain of stations fully occupied with fast and accurate traffic at a low rate would result in a heavy financial loss for generation, interest, depreciation and operation, unless it had been so designed and constructed as to avoid a huge initial capital outlay and au excessive annual expenditure for maintenance and operation.
Of the financial results of existing long-range wireless services we have no knowledge, but as regards only speed and accuracy, including the avoidance of excessive repetition, we are of opinion that no satisfactory commercial wireless service, as we have defined the expression, is in operation anywhere to-day over a distance of 2,000 miles.*
10. The problem of so designing and placing the Imperial stations as to combine a remunerative speed and reliability with a cost low enough to afford reasonable expectation that the service will soon become self-supporting, is a difficult one and has required most careful consideration. The solution we recommend departs widely from the general direction of contemporary practice. We believe it to correspond with the present stage of wireless science, which is one of rapid advance, almost from month to month, in that the developments it is reasonable to anticipate will form a natural continuation of the plan we propose. The objects desired might perhaps be secured by other and more conventional methods, but by none, in our opinion, not involving an enormous immediate capital expenditure and a heavy annual loss, which the scientific progress of a few years might well
to have been unnecessary. prove Our proposals arise from consideration of the history and present practice of wireless communication over long distances. A brief statement of these is therefore necessary.
11. The methods of generating powerful electro-magnetic waves for the transmission of signals to long ranges are four in number:--
(a) Spark Systems.-The discharge of a condenser across a spark-gap was the original method. The gap may be single or rotating, as at the Marconi stations of Clifden, Glace Bay and Coltano; at the Eiffel Tower; at Cleethorpes, and formerly at Horsea; multiple, as in the Telefunken "quenched spark" systems at Nauen and Sayville; or of the specially rapid sparking type, in which the sparking is controlled by the rotation of different discs, as in the Marconi "timed spark" stations of Carnarvon and Stavanger (Norway).
These systems call for no comment here, as, although the pioneer work of the past stands to their credit and Stavanger carries on fairly regular communication, duplex, and for short periods at above hand-speed, with America (8,554 miles), it would hardly be proposed by anybody to equip new long-range wireless stations with system.
form of spark
any
See pp. 3 and 4, footnote. We are not acquainted with the working results of any commercial wireless service in operation from the Pacific coast of the United States.