Page:Popular Science Monthly Volume 88.djvu/335

 A Mexican Radio Station

��By Stanley E. Hyde

��IN MEXICO at present there are eight radio stations, situated at Vera Cruz, Campeche, Obispo, Maria Madre Island, Mazatlan, San Jose del Cabo (end of Lower California) Santa Rosa- lia and Guaymas. During the recent troubles in Mexico the rebels destroyed the station on Maria Madre, which is one of a group of three Pacific Coast

���Fig. 2. Plan of counterpoise

��islands belonging to Mexico, situated about ninety miles southwest of the State of Tepic. These islands, ex- tremely barren and practically void of vegetation, are surely a most uninviting place for a radio operator.

The station illustrated is that of the Federal government completed during the present year at Mazatlan, Sinaloa, the largest Mexican city on the Pacific Coast. The station is on the top of a hill back a little from the city, and over- looks the ocean. On the side of the hill are broken down barbed-wire fences in great confusion, erected by the Federals to hinder the advance of the rebel forces which about a year ago tried to capture Mazatlan by land and sea. Upon reach- ing the station one is greatly surprised to find a moderntsteel tower for support- ing the antenna. It is square and grad- ually tapers to the top, on which is an observation platform which can be made useful for military purposes. The

��whole, constructed of thin structural steel, is 250 feet high, and guyed by steel cables anchored firmly in the earth. The antenna, which is illustrated in Fig. I, has distinct features not found in the ordinary radio station, and is especially adapted to the tropic^ where the static is troublesome. It consists of four wires spread out umbrella style, but not connected together at the bot- tom. The four spans are brought to- gether near the top and the leads run down from the highest point, as illus- trated in Fig. 3.

On such rocky and dry soil it would be impossible to obtain an efficient earth connection so a counterpoise or artificial serial is made use of. Fig. 2 shows a plan of this, which consists of wires supported 18 feet off the ground and insulated from it. These wires are also connected together at the tower ter- minal and brought into the station through a large lightning switch.

The radio building is constructed of brick and has a red tile roof. Two rooms are used for the transmitting and receiving instruments, while the other three are for the use of the operator and his family.

The transmitter is a I14 kilowatt Telefunken set, using a 500 cycle alter- nator, belted to a ten horse-power dis- tillate engine. Directly connected to the

��Antennas

���Fig. 3. Diagram of station at Mazatlan, Mexico

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