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COMMUNICATIONS, as A\pplied to the Merchant Marine BY CAP, 3 3. bi Pe the development of a _ device utilizing reflected under-water sound, which will make it possible for ships to detect the presence of icebergs which might menace their safety. See are being made toward Commercial Communications Under the heading of commercial communications we find the following types of service offered: (1) Radio telegraph service, be- tween ship and shore or ship and ship, regardless of whether similar nationalities: or companies are in- volved, for the transaction of mat- ters concerning the progress of the voyage, orders to vessel, etce.; and for transaction of business or person- al matters of passengers or crew. This service is as simple and reliable as the ordinary domestic telegraph service. Press service is also provided by this means, which permits every- one at sea to maintain touch with events of both local and international interest. Shipping companies often utilize secret code methods for com- municating important or confidential orders or information to and between their vessels at sea. (2) Radio telephone service for the same purposes outlined for radio telegraph service, especially when personal contact is desired. In cer- tain cases, direct connection may be had to any telephone subscriber with- in the confines of an entire country. (3) Radio facsimile service be- tween ship and shore and between ships, affording facsimile transmis- sion of sketches, plans, documents, or photographs in the transaction of business matters for both passengers and shipping interests. It also appears that the reception and transmission of television on board ship may become practicable, and this projected service may prove of benefit both to passengers and shipping interests, although the exact applications are not yet clearly de- fined. International Control of Radio Radio signals are transmitted through space in a wave form, each radio transmitter being capable of sending out signals on one of a num- ber of practically constant wave lengths, or what is the same thing, *The author... Capt: Sic GC. hooper, U. S. N., is director, naval communica- tions, United States navy. This article has been published in two parts. The first part appeared in the August issue. MARINE REVIEW |N this, the second, end concluding part of Captain Hooper's article he continues the discussion of the practical applications of means of com- munications in the merchant marine. The responsibility of the master and his officers in acquiring a broad understanding, and facility in the use of com- munications is emphasized by examples of notable disasters and rescues. He suggests, now that modern progress moves swiftly and is accepted casually, that we do not allow ourselves to be lulled into a false sense of superiority; but rather that we make every effort to master the facilities that have been devel- oped for the increased safety and certainty of navigation. at a constant number of wave cycles per second. Inasmuch as the number of cycles per second, or frequency, is generally a figure of considerable magnitude, the term ‘‘kilocycles’’ is employed for convenience. With transmitters and receivers tuned to frequencies sufficiently well separated in the radio frequency spectrum, it is possible for many radio stations to operate simultaneously without inter- fering with one another. However, this necessity for channel separation limits the total number of channels which are available for radio com- munication purposes in any particu- lar region of the earth. Although the first application of radio was to maritime requirements, the practicability of employing radio for other purposes was soon appar- ent, giving rise to such services as point-to-point radio telegraph, radio telephone, broadcasting, television, radio-beacon, and aeronautical radio communication, As these services grew, they demanded more channels in the radio spectrum, and the re- sulting situation was chaotic, to say the least. It was finally brought home to all progressive nations of the world that international alloca- tions of frequency bands in the spec- September, 1934 trum to specific services was impera- tive, Accordingly, by an international convention, allocations were made on this basis, although in every case all nations could not agree, and it was necessary to include several region- al arrarrangements. By the conyen- tion, maritime radio was restricted to certain specified frequency bands, and these have proved to be just sufficient to care for mobile commun- ications. That convention was for- mulated in Washington in1927. Since that time, other services, particular- ly broadcasting, have made deter- mined attempts to obtain further space in the radio spectrum at the expense of the mobile or maritime services. Thus far, these attacks have been repulsed, but the danger from encroachment by other services still remains. The value of the international con- trol of the radio spectrum and methods of transmission, includ- ing the elimination of all re- gional agreements, is readily ap- parent. With standardized alloca- tions the mariner may proceed from one part of the globe to another without fear that his radio service is jeopardized by other services, or that his equipment cannot be used because of variations in regional reg- ulation. It must be realized that no one has a greater right to the bene- fits of radio than the merchant ma- rine, but unless the officers of that service insure proper use of frequen- cies and equipment on their own ships, and realize that unless this is done other radio interests will ac- quire by one or another method a part of the present internationally al- located mobile maritime radio spec- trum, there can be no absolute assur- ance of satisfactory future radio sery- ice of either distress, navigational or commercial nature, Responsibility of Shipmasters Some years ago radio was a mys- tery to most persons, and those who did have a little knowledge of the subject were considered wizards. Nowadays even the general public has a vague notion of the meanings of such words as kilocycles, antennas, keys, microphones, head phones and the like. The cloak of mysticism surrounding the radio has been dis- counted; even young boys of today are building and operating their own radio equipment successfully, It has 19