Patent GB-772018-A (GB)
Title: Automatic code senders for beacons
IPC: H04L25/20
Filed: 1954-06-28
Abstract: 772,018. Electric signalling systems. SVENSKA AKTIEBOLAGET GASACCUMULATOR. June 28, 1954 [July 3, 1953], No. 18861/54. Class 40 (1). A radio-beacon which transmits a characteristic signal consisting of a pair of morse letters twice slowly and then thirty times rapidly at predetermined times includes a number of relay chains for controlling the timing and sequence of operations and for composing the transmitted signal which can be changed by modification of the wiring of a jumpering frame. The beacon also includes a radio receiver whereby its normal action is initiated and by means of which it can be made to give periodic audible signals, and to alter the period of its radio signals in fog. Generation of morse signal. On the operation of 113, Fig. 1, by the timing circuit described in another paragraph, opposed winding 11<SP>1</SP>, 11<SP>11</SP> of a relay 11 are energized respectively via resistor 13 and capacitor 16. Operation of the relay is thus delayed until the capacitor is nearly charged, whereupon it operates and opens its energizing circuits. The capacitor then discharges via both windings (which in this circuit act in the same direction) to delay the relapse of the relay. When this does take place, the energizing circuits are re-made and the sequence is repeated. At the beginning of each odd pulse, 22 is operated and at the end 23 is operated over winding 231. Each even impulse holds 23 over its winding 23<SP>11</SP> and releases 22. In consequence, the make-and-break periods of 22, which controls the signal generation, are exactly equal. The first operation of 22 energizes 29 which holds until the next impulse in series with 30<SP>1</SP> which operates relay 30 at the end of the first pulse. This relay holds in series with 31<SP>1</SP> during the second pulse and then falls, 31 then holding over its winding 31<SP>11</SP> in series with 32<SP>1</SP>. The rest of the chain is built up in a similar way, the odd-numbered relays being operated during a mark and the following space and the even-numbered relays during a space and the following mark. Contacts of this chain are jumpered to negative lead 68 so as to produce the appropriate morse signal in lead 73 which controls a radio or a subaqueous or other sound transmitter through a sluggish relay 82. Sequence of repeated signals. On the operation of 38 at the end of the signal generating chain 84, Fig. 2, pulls up and locks in series with 89<SP>1</SP> when 38 falls back. 89 energizes 85 when the signal has been sent a second time, 84 is released and shortly afterwards 89, and 90 pulls up over 90<SP>1</SP> in the holding circuit of 85, and energizes 86 which energizes 94. The latter substitutes resistor 14 for resistor 13 and capacitor 17 for capacitor 16 to increase the speed of impulse generation by relay 11. The next operation of 38 re-operates 84 and the chain is finally counted out when the signal has been sent thirty-two times. Clock-controlled timer. Apparatus 110, Fig. 5, delivers a 2-second pulse to relay 111 once per minute, 111 prepares a circuit for 113, Fig. 1, and repeats the impulses from 110 to a relay pair 128, 129 arranged so that each odd impulse energizes 128 and each even one releases it. 128 delivers impulses to a chain 130, 131, 132 which operate in turn in synchronism with odd impulses from 111 and after each period of six minutes, return to their original state. Relay 130 passes on impulses to a pair 138, 139 similarly controlling a chain 140 . . . 144, the relays of which are energized in turn every twelve minutes and the whole operation repeating itself every hour. These relays and the relays 130 . . . 132 control lamps, Fig. 7 (not shown), which thus indicate to the nearest twominutes how much of each period of 1 hour has elapsed. Under normal conditions the timer arranges for the beacon to transmit during the third and fourth minutes of the first and second six-minute periods of each half hour, but in foggy weather transmission takes place at intervals of four minutes through the hour. Modifying action by radio or other remote control. A signal impulse received by 191, Fig. 6, energizes 192 to repeat the impulse to a control pair 196, 201, provided that the beacon is in the first of each pair of six-minute periods and, i.e., when 138 is energized. 196 energizes, and when the impulse ceases 201 is energized in series with 196 and closes the circuit of an indicating lamp 204. When the relay 131 operates, 195 pulls up and locks, and through contact 151, Fig. 1, and contacts 154, or 155 and 156 in series energizes over line 157 the radio transmitter during the second, third and fourth minutes of the first and second six-minute periods of each half-hour during clear weather, thus allowing the valves of the transmitter to be heated ready for transmission in the third and fourth minutes. 195 also prepares a circuit for relay 82 for keying the signal, and for the starter relay 113. Relay 194 is normally operated at each operation of 138 and 139 and locks, but is released when 201 comes up at the end of the control pulse. If the control pulse is continuous, 194 remains operated, and through contact 153, Fig. 1, the transmitter is switched on during alternate three-minute periods to give the foggy weather signal, and the starter relay 113 is energized directly from the supply over contact 120. Relay 194 also controls the transmission of audible fog signals which are coded by the counting arrangement of Fig. 2, some of the relays having contacts as shown in Fig. 4. If a second control pulse is received while 138 is energized, 195 remains energized and 194 is de-energized, and clear weather signals are sent as with a single control pulse.