Harry Shoemaker - Wireless

Wireless

Harry Shoemaker testified that in April, 1895, when he was a boy of 16, he constructed and used a complete system of wireless telegraphy, which was a complete anticipation of the patent in a court case concerning Marconi's patents. One of the earlier arrangements by Mr. Shoemaker is an oscillator consisting of two balls connected with the usual induction coil. These balls are separated by two other balls, the latter within a box containing a gas dielectric under high pressure. This arrangement, the shoemaker systems, is claimed, obviates the retardation of sparking under oil. The coherer used with this system consists of a tube in which are contained the filings. Immediately above the filings a small iron ball is placed in a suitable receptacle. Above the ball is the pole-piece of a magnet controlled by the relay in the coherer circuit. The movement of this ball within the tube when acted upon by the magnet suffices to decohere the filings.

Another device by Shoemaker consists of a receiver which comprises a plurality of plates in inductive relation to one another, and means for permanently charging such plates, together with a microphone circuit operated by the plates. Mr. Shoemaker has also designed a wireless telegraph repeater consisting of a detector aud a relay controlled thereby; a circuit controlled by the relay which insulates the coherer and simultaneously closes the circuit; also means for restoring the coherer and for the generation of retransmitted energy.

Shoemaker's most important practical work, however, has been done in connection with the International Wireless Telegraph Company, are the transmitting and receiving circuits. The radiant energy is primarily set up by a generator developing 110 volts, which are raised to 25,000 volts by transformer. This E. M. F. charges a capacity, which discharges into the closed oscillating circuit and thence into the aerial wires, of which there may be two or more (not joined at the top), via small arcing spaces, about .03 inch apart, similar to those shown in the De Forest system. Shoemaker founds that much depends on the form of energy transmitted, and had obtained best results with large capacity and small inductance.

A patent, U.S. Patent 824,676, for a wireless telegraph system, granted to H. Shoemaker and International Wireless Telegraph Company contains a wireless signaling system in which an aerial conductor, an earth connection, wave-responsive devices connected in parallel with each other and connected to separate condensers between the aerial conductor and earth connection, and a local circuit including the wave- responsive devices connected in series with each other.