US960631A - Wireless signaling. - Google Patents

Description

I R. A. FESSENDEN. WIRELESS SIGNALING. APPLICATION FILED OOT. 10,-1901.

960,631. v Patented June 7, 1910.

2 SHEETS-SHEET 1.

R. A. PESSBNDEN. WIRELESS SIGNALING. APPLICATION FILED 001210, 1907.

960,631 Paten te d June 7, 1910.

2 SHEETS-SHEET 2.

l i i i, I o e. e 9

REGINALD A. FESSENDEN, OF BNT ROCK, MASSACHUSETTS.

Specification of Letters Patent.

wInELnss sldnamno.

Patented June '7, 1010.

Application flied October 10, 1907. Serial No. 398,817.

My invention relates to Wireless s1 aling and more especially to means for t e prevention of interference.

In the accompanymg drawings forming a part of this specification Figures 1 and 2- are diagrams ofcircuits' for sending. Figs. 3 and 4 are diagrams of modified arrangements of circuits for receiving. Figs. 5 and 6 show respectively a central section and a side elevat1on of a form of generator for generating the electroma netic waves. d escribed has for its The invention herein object the more eilicient production and receipt of wireless signals, and the production of such signals without interfering with other" stations, and the receipt of such sigthe spaces are sent and not the male without interference from other stations.

In 1, 11 is a high frequency alternoting ynamo, 12 a tunin inductance, 13 an antenna which may be either of the loop type, in which case it is preferably though not necessarily ungrounded, or of the verti-, cal type as shown, being in this case preferably grounded as at 14. 15 is the field of the lug frequency dynamo, 10 the source of current excitin the field, and 17 a telegra h key, whic on being depressed to form a at or dash, opens the field circuit and stops the emission of the h1g1 frequency waves. It will be seen that when the hey is in its normal position waves are being sent out and when depressed waves are not sent out, consequently with this apparatus 'ots and dashes as in the usual method.

Fig. 2 shows an alternative method which 13 is the antennae, 18 the secondary of a transformer, 19 the primary, 20 a capacity, 21 and 22 inductances,23 a he short .circuiting the inductance 22, 24 t e secondary of a second transformer, 25 its primary, 26 -1 capacity, 27 an inductance 29 a compressed gas spark ap, 30 an adjustable resistance, 31 a source 0 continuous current. With this apparatus, the couplings of the transformers 18 19 and 24, 25, respectively,

are preferably diflerent, though not neces. sarily so. That is, preferably, the coupling in one of the transformers may be tight and the other loose; as for example,the coupling between 18 and 19 may be tight and that between 24 and '25 maybe loose, or vice versa. The waves are generated continuously but by depressing the key 23, the frequency of the waves is altered. Instead of using the spark gap 29, a high frequency alternating current dynamo 33 may be used by throwing the switch 32 as shown. The electrical constants of the circuit are preferably so arranged that the frequency will be less than 100,000 where it is desired to send over long distances, as applicant has dis covered that the absorption over long distances is very much less for frequencies of 100,000 and under, and that with trequencies of 50,000 for example, there is comparatively little absorption up to distances of 2,000 miles during. daylight, whereas with frequencies of 200,000 there is almost a total absorption.

Applicants invention includesthe broad discovery that, contrary to the statement by Fleming and Marconi at page 618in the formers work on electric wave telegraphy, the absorption does "not increase with the wave 1en'gth,.but instead, it reaches a certain maximum varying with the conditions but roughly between 100,000 and 200,000, and then decreases with great rapidity as the Wave length is increased. Applicant therefore uses wave lengths beyond the point of maximum-absorption and as a rule lower than 100,000 per second, though not so low as to prevent ethcient signaling.

In Fig. 3, 34 is a receiving antenna grounded at '37 35, 36 are the primary and secondary of a transformer, the secondary 36 being connected to the demagnetizing coil 38. 39 isan adjustable capacity and 40 an audible frequency. The iron Wire 41, haw

ing thus impressed upon i a succession of variations of magnetism of a frequency to form a musical note, traverses the poles of the annulling magnet 38 and under normal conditions the magnetism is wiped ofi' so as to produce no effect in .the 0011 -51 and the telephone 52. But when the key 17 in Fig.

, phone 62 when no si 1 is depressed, and the transmitted impulses interrupted, the portions of the wire upon which the musical note has not been wiped off travel through the poles of the magnet 51 and produce a musical note in the telephone 52. In this way it will be seen that the inverted sending is corrected by an inverted receiving and dots and dashes come out as musical notes.

In Fig. 4, 34 is the receiving antenna grounded at 37, 35 and 36 are the primary and secondary of a transformer, 39 a variable capacity, 40 an inductance, 53 a receiver, for example a liquid barretter or tellurium receiver, 54 a tuning fork vibrator producing a musical note, through the primary 48 and secondary 49 in the divided circuit 55, 53, 56 and 55, 57, 58, 56. 57 is a capacity and 58 an adjustable resistance. 60 and 61 are secondaries of the transformer connected to the telephone receiver 62. The resistance 58 and capacity 57 are so adjusted that a continuous sound is produced in the teleals are being received, but when signals 0 the strength produced by the proper sending station are receivedthe two divided circuits become balanced and no sound is heard in the telephone 62. This accomplishes the same purpose as the devicp shown in Fig. 3, 2'. e. reinverting the $1 a s.

1g. 5 shows an alternator of the well 7 known Mordey type, but designed to give high frequencies and having two air gaps and armatures. In this figure 63 is a revolving field inductor disk which may have the same number of field teeth on both edges but preferably has 1/5 of one per cent. more on one side than on the other, so as to make the frequencies generated by the two armatures also diifer, say 1/5 of one per cent, from each other. 64, 65 are two armatures supported by frame 91 carrying, on rods 88 and 85, dash pots 87 and 93 the bearings 66 and 67 so as to be always concentric with the shaft 68. 69 is a field coil and the position of the armature winding 92 is shown in dotted lines in Fig. 6. 70 and 71 are capacities. The armature 65 is in series with the coil 72 and the armature64 with the coil 73. These coils are grounded as shown at 75, and the other terminals of the armature are grounded on the frame of the machine which is grounded at 76. The two coils 72, 73 are at right angles to one another so as to exert no inductive efi'ect on each other. 77 is a movable coil capable of being rotated on the detially as described.

72, so changing the frequency while kee ing the intensity constant. One terminal 0 the coil 77 is grounded at 74 and the other is -=connected through the tuning inductance 83 to the antennae 84. In this Way on depressing the key 78, the frequency is changed.

Fig. 6 is a side view of the alternator shown in Fig. ,5, and shows the springs 85, 86 and dash pots 87, 88 whereby the armature is supported flexibly and yet concentrically on the shaft 68. -By the invention herein disclosed no disturbance is produced by a sending station on other stations unless they are exactly on'the same tune to 1/5 of one per cent. Also it is practically impossible to interfere with a receiving station operating by this method,and very diflicult to read messages, since they are sent 1n.1nverted form.

Having thus described my invention, what I claim as new and desire'to secure by Letters Patent, is the following:

1. In apparatus for transmission of electric energy, the combination with a generator of practically continuous impulses at the sending station and a device to modify vices by which the combine effects of the f locally generated and the received impulses normally annul each others efi'ects, whereby when the sent impulses are modified in character, an indicating efi'ect is produced by interrupting said normal mutual annulment 2. Apparatus for wireless telegraphy comprising a generator of continuous electric impulses at the sending station and a device for modifying them, a generator of continuous impulses at the receiving station, and devices operated by the combined eflects of the 10- callyogenerated and the received impulses to pr uce a musical note only when the impu ses are modified in character, substan- 3. Apparatus for wlreless signaling comprising a generator of ractica y contlnuous impulses of inaudible requency at the sending station and a device to alter their normal character, a generator of practically continuous impulses at the receivin station, and devices operated thereby to e set a normal suppression of eii'ect, but permittin an indication b the received waves w en the same are a tered in character, substantially as described.

4. In apparatus for wireless telegraphy, includin a sending station having a generator o sustained oscillations operatively connected to the sending antenna, and a key for controlling the emlssion of the electromagnetic waves so produced, a receiver operatively connected to a receivin antenna, and devices to produce a musica note corresponding to the signals sent from the sending station, but the pitch of the musical note being determined by the apparatus at the receiving station and being independent of the apparatus at thesending station.

5. Apparatus for wireless signaling comprising means for practically continuous generation of electroma netic waves, means at the receivin station or producing a continuous flow 0 impulses and means for normally annulling. their tefiect by impulses received, except when the normal character of the sent impulses. is altered, substantially as described.

, 6. Apparatus for wireless signaling comrising electric means at a receiving station or continuously (producing a musical sound, means at the sen ing station to continuously generate impulses and means at the receiving station whereby said impulses silence said locally produced sound,'except when the sent impulses are interrupted 'for signaling.

7. Apparatus for signaling comprising means at a sending station to continuously generate impulses, means at a receiving station to continuously generate impulses and means by which the sent impulses normally annul their efiects, whereby a signal is made by altering the normal character of the sent impulses.

In testimony whereof, I have hereunder signed my name in the presence of the two subscribed witnesses.

REGINALD A. FESSENDEN.

Witnesses:

Jnssm E. BENT, Annnumu WOLEVER.

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