Patent GB-190801848-A (GB)
Title: New or Improved Apparatus for Alternative Wireless Telegraphy and Telephony.
Inventor: SCHIESSLER JOSEF
Filed: 1908-01-27
Granted: 1909-01-27
Abstract: 1848. Schiessler, J. Jan. 27. Wireless telegraphy and telephony; converting alternating and direct currents.-In a system of alternative wireless telegraphy and telephony, the high-frequency currents produced in a Duddell circuit are superimposed upon a part of the continuous - current circuit supplying the arc, and are then conveyed to the antenna system comprising two Lecher conductors in which stationary waves are produced. By means of change - over switches, the transmitting and receiving apparatus may be connected for telegraphy or telephony. In the telegraphic receiving - apparatus, the received waves vary the field of a luminous arc, the vibrations of which are recorded photographically, or rendered audible by a light-sensitive cell and a sounder or telephone. The direct-curreut generator 1 supplies current through the switch 2 and choking-coils 5, 7 to the Duddell arc 12, 13, the oscillation-circuit 25, 26, 27 of which is inductively associated with the transformer coil 30, adapted to superimpose the high-frequency currents upon the coil 6 in the direct-current circuit. The coil 6 may be replaced by a second luminous arc, the field of which may be varied by the coil 30 or by a magnetic deflector (shown in Fig. 2, and described later) receiving its current from the coil 30. The high-frequency currents thus produced pass through the condensers 31, 32 to the coils 37, 38, loosely coupled to a closed oscillation-circuit comprising two parallel wires, each of half-a-wave length, wound into coils 39, 42 and 40, 43, respectively, and an adjustable condenser 41. The double antenna, loosely coupled to the coils 42, 43, comprises two parallel wires, each of half-a-vave length, wholly or partly wound into two long coils 44, 45, connected at the top by a choking-coil 48 and at the bottom to condensers 49, 51 and choking-coils 50, 52. Stationary waves are thus produced in the double antenna, which may be regarded as a Lecher system. The change-over switch 14 can connect the telegraph or the telephone transmitting apparatus in shunt with the arc 12, 13. The microphone 20 is connected by the resistances 17, 18 and fuse 19 to the oscillation - circuit 17; shunting the arc. If the resistance 17<1> is inductive, the resistance 18 may be dispensed with. When the apparatus is arranged for receiving, the switch contacts 35, 36 are connected to contacts 53, 54, and the switch 2 engages contacts 80, 81. For receiving telegraphic messages, the switch 55 is placed in the position shown in Fig. 1, current from the generator 1 then passing through the luminous arc 62. The received waves pass from the antenna system through the switchcontacts 35, 36, 53,.54, 56, 57 to the transformer primary 58, the secondary. of which is connected to the condenser 60 and to a double solenoid .61 arranged to influence the arc 62. The movements of the arc are recorded photographically on the drum 87. The tuning-fork carrying the mirror 83 may be tuned to a similar fork acting as interrupter at the transmitting-station and to the note of the arc 62, in which case the arc is provided with a shunt containing capacity and inductance. A system of mechanical tuning is thus produced. The solenoid 61 may be replaced by the magnetic deflector shown in Fig. 2, in which a core of annealed, coppered, and varnished soft-iron wires is provided with-two coils 89, 90 energized from the transformer 58, 59. When the switch 55, Fig. 1, engages the contacts 74, 75, 76, the received waves pass to the transformer 71, 72, and influence the telephone 79, no detector being used.