Page:Popular Science Monthly Volume 89.djvu/653

 Popular Science Montldi/

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��Converting a Freight Car Into a Wireless Station

WHEN the United States troops went into Mexico, they were forced to meet a number of unusual conditions. In Vera Cruz, for example, they found new and difficult situations and their ingenuity in overcoming some of these hanflicaps is interesting.

A train was run twice daily under a flag of truce from Vera Cruz to the interior. This was always accompanied by a small guard. Inas- much as a treacherous attack upon the cars was likely it was considered communication

���The exterior view of the car with aerial on top

��to occur at any tmie, desirable to keep in with the train. Since this could not be accomplished in any other way than by wireless, a complete installation was made in one of the passenger coaches. An upright was erected at each end of tlic car, and aerial wires were strung between cross-arm? mounted upon

these. The in- -~- ' '

struments themselves were placed upon the cusiiioned scats within the car, thus avoiding difficulty from vibration. The ground connec- tion was made through the trucks of the car, and power for the trans- mitter was supplied by a small hand-

��when the latter was in motion.

When the Arm\' landed, the Navy men were relie\ed of guarding the city and train, and the Signal Corps took over the wireless work. A small gasoline- driven motor-generator was placed on the train, and the satisfactory work was continued until the main railway line was reopened and through trains began

running be- tween Vera Cruz and Mexico City, some months later.

A new Headquar- ters station was erected on the roof of the Terminal Railway Station, hav- ing a four-wire umbrella antenna sup- ported from a40-ft. pole, and maintnined constant communication with all the neighboring plants as well as with the ships in the harbor. By use of the net- work of wireless and buzzer-systems it was possible for Headquarters to learn instantly of conditions at all the outposts. A narrow gage railway line connected Vera Cruz with

7 the detached

post at EI Tejar, about nine miles south, and the train wireless e<iuipment was transferred to cars run over this division. No passenger coaches were available, so a framework with a flat-top aerial abov-e it was built upon one of the springlcss flat- cars. When the was also train was still this worked well, but with the cars in motion there was so much

���Interior view showing the apparatus in working order power genera- tor. A fixed radio station installed at headquarters in Vera Cruz,

��and messages were exchanged between this plant and that on the train, even

��vibration that a springboard was ranged to support the apparatus.

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