Page:Popular Science Monthly Volume 88.djvu/178

 Radio Stations in Alaska

��By Vincent I. Kraft

��RADIO communication plays an im- portant role in Alaska. Many cities and towns which would otherwise be iso- lated are kept in touch with the rest of the civilized world by this agency alone, and the United States Government em- ploys it to communicate with govern- ment vessels in North Pacific waters, and to receive the weather reports from all parts of the northland. Remote as Alaska is from the source of radio in- ventions and improvements, the Alaskan stations represent strictly up-to-date methods of radio communication. During the past ^^j.s' /o^er few months a great deal of construc- tion work has been done in Alaska, both in improving the existing sta- tions, and in the erection of new ones. The past year has witnessed the completion of the Ketchikan unit of the new chain of semi-high-powered stations. Here the Marconi Company has built a 25 kw. plant, which is at present in daylight communication with a similar outfit lo- cated at Astoria, Oregon. This first span of the new chain is over a dis- tance of 640 nautical ' miles, and con- nects Ketchikan, the southernmost city of importance in Alaska, with the United States. Astoria was chosen as the United States terminus of the chain, after a series of tests in many parts of Washington and Oregon, on account of its natural adaptability to Alaska work. Another station, of ten kilowatts ca- pacity, will soon be erected at Juneau, the capital of Alaska, and will be within daylight range of the Ketchikan station. The erection of a fourth station, in the vicinity of Seward, the terminus of the new Government railroad, is contem- plated. Other stations will probably be erected later.

This chain of stations will be capable

���20 /v/res eac/) /ooo ' /ong Diagram of the antenna system at Ketchikan, Alaska

��of rendering service that the United States Army cable does at present, be- tween the United States and the above- mentioned points. Experiments are still being conducted between Ketchikan and Astoria, the longest of the spans, and although the wave lengths that will be employed in actual commercial com- munication had not been definitely de- termined upon up to last August, it had been found comparatively easy to cover the distance satisfactorily, using waves between 3,000 and 5,000 meters in length. Signals ranging in strength from 1,000 to 1,500 times audibility are received at Ketchi- kan from Astoria in daylight, and this intensity is considerably more than necessary for good commercial operation, employ- ing a typewriter at the receiving sta- tion.

The installation at Ketchikan, the largest of the stations of the new chain, includes four steel towers of the self- supporting type, 315 feet in height, be- tween which is supported an antenna of 20 wires 1,000 feet in length. The sta- tion is equipped with a 60-cycle trans- mitter of 25 kw. rated capacity, provided with a synchronous disc discharger. The transmitter is able to operate at 100 per cent, overload. The receiver is of the standard Marconi panel type, adapted to the reception of waves up to ten thou- sand meters in length. The station at Astoria, Oregon, is a duplicate of the Ketchikan installation.

The United States Navy, which has maintained stations for many years in Alaska, is improving its present installa- tions and building new ones. The sta- tion at St. Paul (Pribilof Islands), since its erection some four years ago, has been equipped with a set of five kw. capacity Telefunken apparatus. The

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