A Personal Narrative of the Early Days of Wireless by One of the Few Men Who were Helping Start the Wheels Almost Before There were the Necessary Tracks
The men who built the wireless apparatus during the winter of 1901 and 1902 in the shop of the Carstarphen Electric Co., Denver, Colorado. Mr. W. P. Carstarphen is the tall bald man in the rear. Mr. G. T. Swenson who later became Mr. Marriott's assistant in the California work is the man in the checked shirt in the center. Mr. Marriott is at the left with his hand in his pocket. He says he was trying to raise a beard to look old enough for his job. He was twenty-two
The coherer detector, decoherer, relays, sounder, tuning transformer, and tape recorder are shown on the large board. At the right is shown a contact type detector with telephone receivers. In this contact detector, steel balls floating on mercury were brought into contact with a strip of aluminum or oxidized iron. The contact pressure was varied by screwing a thumb screw in or out of the mercury. The phones used were the adjustable-magnets, watch-case type of Stromberg Carlson phones, rewound with fine wire (36 or 40 B&S). Note the leveling screws on the coherer receiver board; not only were these necessary but the coherers had to be very carefully made, exhausted by a mercury pump and the circuits screened by a metal case as we screen circuits now. Taken in Denver, March, 1902.