Patent GB-190704137-A (GB)
Title: Improvements in and relating to Wireless Electric Signaling Systems.
Inventor: CABOT SEWALL
Filed: 1907-02-19
Granted: 1908-02-19
Abstract: 4137. Cabot, S. March 10, 1906, [date applied for under Patents Act, 1901]. Telegraphs. - Relates to d i p l e x, duplex, quadruplex, and multiplex wireless telegraph systems, which may be associated with similar wire telegraph systems and with intermediate wireless relay stations. Fig. 2 shows a diplex or duplex terminal station, Fig. 3 a two-way diplex or duplex wireless relay station, and Fig. 4 the other terminal station. The frequencies at which the various aerial conductors work are indicated at T<3>, T<5>, R<7>, R<10>, &c., the aerial V<1>, Fig. 3, being adapted to transmit waves of the frequencies '3,' '5,' and the antenna V1<1>, being adapted to receive waves of the frequencies ' 7,' '10.' The transmitting- keys K, K<1>, Fig. 2, are normally closed. If the key K<1> be opened, the relays 1<1>, 2<1> are de-energized, the relay 2<1> cutting out the wave-detector P' corresponding to the frequency '3,' and the relay 1<1> causing the transmission of waves of frequency ' 7' from the transmitting aerial. During the transmission of these waves, the sounder 81<1> is de-energized, but every depression of the key K<1>, which produces a break in the train of waves, causes the hammer of the sounder to be attracted. The 'back-stroke' Morse wireless signals which are thus transmitted with the frequency '7' are received by the aerial V1<1>, at the relay station, Fig. 3, and affect the wavedetector P2<1>. The relays 9<1>, 7<1>, 11<1> are consequently energized, and waves of frequency '3' are given out by the aerial V<1>. Every break in the train of waves received by the aerial V1<1>, causes the armature 70<1> to fall back and energize the sounder magnet 71<1> at the 'way' station y. The waves of frequency '3' transmitted by the aerial V<1> are received by the aerial at the terminal station Z, Fig. 4, and affect the wave-detector P<1>. The relay 5<1> in consequence throws the resistance R<1> into the line I'. The reduction of current so affected does not de-energize the relays 2<1>, 1<1>, but de-energizes the relay 8<1> and sounder 81<1>. Every break in the train of waves consequently produces a `front- 'stroke' signal on the sounder. The key K at either station may be simultaneously used to send an independent message, the frequencies '10,' '5' being used in that case. The lines I, I<1>, Figs. 2 and 4, which connect the keys K, K<1> with the wireless system, may be short lines within a single building, or may be wire telegraph lines. The receiving operator at a terminal station can 'break' at any time by opening his key. By using aerials capable of radiating or receiving waves of three or more different frequencies at the terminal and relay stations, a multiplex system may be provided. Fig. 7 shows a terminal station of a duplex system. Depression of the key K does not affect the receiving-relay 14, but operates the transmitting- relay 16 so as to send trains of waves from the aerial V. Waves received by the aerial V<1>, which is tuned to a different frequency, affect the wave detector P and energize the relay 18 so as to shortcircuit the resistance R<4>. The increased current in the line I<3> produces no effect on the transmitting- relay 16 but energizes the receiving relay 14. A bridge or differential quadruplex system, with or without intermediate relay stations, may be worked in a similar manner. Specifications No. 28,550, A.D. 1902, and No. 9422, A.D. 1906, are referred to.