US1962611A - Radio communication - Google Patents

Description

June 12, 1934. A. NYMAN RADIO COMMUNICATION Filed Sept. 8. 1926 4 Sheets-Sheet l nun ll/W/l/ I1 I 1.11 .1 I l 1 I d IN VE N TOR a/exander Nyman a Y 74%;?

HTTORP/EY June 12, 1934.

A. NYMAN 1,962,611 RADIO COMMUNICATION Filed Sept. 8. 1926 4 Sheets-Sheet 2 1 Q m B m %q a T \D N INVEHTOR d/emnder Hym n BY a AT ORNEY June 12, 1934. A. NYMAN RADIO COMMUNICATION Filed Sept. 8. 1926 4 Sheets-Sheet 3 IHVENTOR d/exander I'll man BY r v 7? HTTOEHEY 31 tion are fully pointed out.

Patented June 12, 1934 UNITED STATES PATENT OFFICE 1,962,611 RADIO COMMUNICATION Alexander Nyman, Dobbs Ferry, N. Y., assignor to Dubilicr Condenser Corporation; New York,

N. Y., a corporation of Delaware Application September 8, 1926, Serial No. 134,294

i l 12. Claims.

I have invented improvements in radio communication; particularly the sending and receiving of radio messages. The invention aims to provide a method and apparatus by which l messages can be conveniently and inexpensively sent along electric conductors extending over a greater or less distance to carry electrical current from one point to another, such conductors being generally known as electrical transmission lines. I

A further object of the invention is to provide for the sending and receiving of wired radio messages over electrical transmission lines by apparatus comprising portable devices which can easi- Ely be connected to the transmission line at a desired point and operated to enable wired radio messages to be sent to that point and easily received anywhere within a prescribed radius of the vicinity thereof.

The nature of the invention is set forth in the following description, taken with the drawings which illustrate in preferred form the apparatus by which my invention is practiced, and in the appended claims the novel features of the inven- But I of course reserve the right to make changes in the shape, size and arrangement of the parts or manner of proceeding that come within the principle of the invention, and are embraced within the meanings of the broad terms in which the appended claims are expressed.

n the drawings: Figure 1 shows how radiomessagesmay be sent along a power line to a given point and there i distributed;

Figure 2 shows diagrammatically the kind of receiving set which is employed; and

Figures 3 and 4 are modifications of the apparatus shown in Figurel.

The same numerals identify the same parts throughout.

Referring first to Figure 1, I show at l a pole or tower having a cross-arm 2 at the top to support the electric conductors 3 of a power transmission 5 line, these conductors being suspended from the cross-arm 2 by strings of insulators 4. It is wellknown that electric waves of high frequency will travel along such a line without interfering with the power which the line transmits. Through the medium of such waves messages can be sent and received at any desired point to which the line may extend. In practice, I arrange for the reception of messages individually along the line 3 at any desired number ofpointsythe messages i reaching the points in question and being there distributed through the vicinity, so that persons in the neighborhood of such points may receive such messages. One of such points of distribution is indicated in Figure hwhere 5 indicates local transmitting apparatus illustrated-as being disposed in a casing 6, suspended from one of the conductors 3. For this purpose I hang a suspension bar 7 at theend of one string of insulators 4, and from the ends of this bar hang rods 8 which pass into the casing 6. These rods may be fastened rigidly to the casing and will be in contact with the adjacent conductor 3, as by having openings through which this conductor passes. Between the rods 8, the conductor 3 will be coiled up in the form of a winding 9. The casing 6 may be of any suitable material, but in the event that it is made of metal, the rods 8 will pass into it through insulating bushings 10, and the inner ends of these rods will be connected by a condenser 11 and coil 12 in series. Thus electric waves passing along the conductor 3 having coil 9 in the line thereof will set up oscillations in the local circuit comprising this coil with the condenser 11 and coil 12, and such oscillations can be radiated by the apparatus in the casing 6, so that the messages can be picked up by anyone for whom they are intended within a predetermined distance.

I prefer to make the appliances within the easing v6 radiate say from one thousand to two thousand kilocycles. The electric waves travelling along the conductors 3 will have a frequency of twenty to thirty kilocycles, and perhaps more, longer waves being more suitable for transmission along the wires, because they follow the wires and are radiated away from them to a less extent than the shorter waves. The apparatus in the casing 6 should therefore receive at twenty to thirty kilocycles or over, and radiate at a much shorter wave length. I further dispose in the casing 6 a modulator and oscillator so that the frequency of the oscillations on the conductors 3 can be converted and given a higher value as required.

The modulator is shown as having the form of a vacuum tube 13 with its grid connected to one end of the coil 12, and its filament connected to the other end of the coil 12 between same and condenser 11. The plate of the modulator tube 13 is connected to a choke coil 14 and thence to'the plate or anode of the oscillator which likewise in the form of a vacuum tube and is shown at 15. The two heated cathodes of the tubes 13 and are joined in parallel by two wires 1'? running to a battery tube 15 is joined a coil 18 at one point, the one extremity of this coil being united to the cathode maining extremity of the coil 18 is led out through the casing 6 to make pendant antenna 21. The battery B which energizes the anodes of the tubes This method affords a very important advantage over the usual device by which a portable set is usually connected to a temporary antenna in close proximity to the transmission line.

23 is connected to the the remaining terminal the lead Z. The circuits anode of the second tube primary of a transformer, of which is also joined to condenser c, the same as the first tube 26. In the second tube 26 the electrical oscillations are detected at twenty to thirty kilocycles and from this second tube they are passed to another trans- The plate of the ceived by the receiver T.

Figure 3 shows another form of instrument for taking oscillations from the line Wires and converting them from the lower to the higher through an opening in the and terminates in an eyelet,

the current constant. in operative relation up so as to The transformer 31 is put by moving the switch 34 bridge over the switch contacts 43 on a plunger 44 operated by a coil 45. This solenoid 45, when the switch contacts 42 are closed, is in series lot ' The oscillations from tubes and 0'.

tube M, and the other terminal'is connected to one terminal of the battery 13,. and by lead 38 to the center point of resistor 38. The anode of the tube M is connected through the choke coil 14 and an iron choke coil 16 to the positive terminal of the battery B. The anode of the oscillator tube 0 is connected through a tickler coil 20 to a point between the high frequency coil 14 and the iron coil 16. The grid of the modulator tube M is connected to the coil 12 of the pickup system, while the grid of the oscillator O is connected to the primary oi the oscillatingtransformer 18. The opposite terminal of this transformer is connected to the negative end of the battery. The pendant antenna 21 is connected through the secondary coil 29 of the oscillation transformer to lead'46 on the negative side of the battery B. The other extremity of the coil 12 is also connected to lead 46. A condenser 19 bridges the coil 18, and an iron core inductance 16 is connected to a point between the coils 14 and 20, and the other terminal of the battery 13. The lead which connects the coil 12 to the battery is shown at 4'7.

When the switch arm 34 is moved upward, current'from the transformer 31 flows through the lead 39 to the filament of the tube M and the filament of the tube 0, returning by way of contacts 42, solenoid45, resistance 3'7 and the lead 33.

wire 3 are used to modulate the output by means of the tube M. The modulations are applied to the oscillator tube 0 and'the signals are thus converted to a higher frequency and then radiated from the antenna 31 which is inductively coupled to the instrument.

I provide a duplicate modulator tube M and a duplicate modulator tube 0. The tubes M and M have their grids and anodes connected in parallel, and so have the grids and anodes of the The filaments of the tubes 0 and M are united at one terminal to one terminal of the filaments O and M, and their other terminals are united by wires 41 to switch contacts 42 to be bridged by a member 43 at the lower end of the plunger 44. If in operation the filaments of the tubes M or O burn out, the coil becomes partially de-energized so that the plunger 44 can drop and bridge the contacts 42, and thus the filaments of the tubes M and O can be heated. On the upward movement, the lever 34, as stated above, actuates the link L to lift the plunger 44 and bridge the contacts 42. This movement makes the lower end of the link L slip past the armA, but the plunger 44 is now held up by the coil 45. If either of tubes M and O burn out and the coil 45 becomes de-energized, the plunger 44 can drop to bridge the contacts 42, and thus put the tubes M and 0 into circuit. Between the filament of the tube M and the lead between the coils l4 and 20 is a condenser 19. The rods 8 have hooks to hang the casing 6 on the conductor 3.

A further form of instrument for taking oscillations from the line 3 is shown in Figure 4, where the casing 6 and contents are hung as before on rods 8 from the wire 3. A lead 4'7, as before, connects one end of the coil 12 to common terminals of batteries A and B, and the other end is joined to the grid of the modulator tube 13. This instrument is arranged to be started by an impulsealong the transmission line to operate a mechanical switch and close the filament circuits of the modulator and oscillator. The switch comprises two coils 48 and 48 in parallel, connected through a crystal detector to the terminal of the coil 12 which lies between the coil and the condenser 11. The common terminal of the coils 48 and 48 are connected to the opposite terminal of the condenser 11, or between this terminal and the rod 8 leading to the line 3. A condenser C bridges the coil 48. From the terminal of the coil 48 connected to the detector 49 a lead 50 runs to the terminal of the coil 48 opposite to that connected to the coil 48, and this coil is also bridged by a condenser C. The coil 48 and associate condenser maybe tuned to a frequency of say ten cycles, and the coil 48 and its associate condenser C tuned to say twelve cycles. The twenty kilocycle oscillations of the wire 3 which have been modulated at, for example, ten cycles are demodulated by the detector 49 to ten cycles to energize the coil 48. This coil will actuate a plunger 44, carrying a switch member 43 to bridge two fixed contacts 42. One of these contacts is connected by a wire 17 to the other terminal of the battery A, and the other contact is connected by wire 17 to the two filaments of the modulator tube 13 and oscillator tube 15. Conductors 17a join the other terminals of the filaments to the terminal of the battery A, joined to the battery B. Hence, when a ten cycle current passes through the coil 48, the switch member 44 will close the filament circuit, and the tubes 13 and 15 will be energized. The terminal of the coil 12, connected to the condenser 11, is united to the grid of the tube 13, the plate of which is connected through a choke coil 14 to the plate of the oscillator tube 15. The grid of this oscillator tube is connected through a condenser C to one terminal of the coil 18, united to a pendant antenna 21. The outside terminal of this coil is united through a condenser C to the plate of the tube 15, and a point between the extremities of the coil is united by a lead 51 to the filament of the tube '15. The terminal of the battery B opposite to that connected to the coil 12 is joined to the lead between the plates of the tubes 13 and 15 through an iron core inductance 16. A twelve cycle signal will take efiect through the coil 48, which is wound in the opposite direction with respect to the coil 48, and move the plunger to carry the member 43 away from the contact 42. The circuit connected to the antenna is the wellknown Hartley oscillating circuit. With the instrument shown in Figure 4, connection can be made with a transmission line at any desired point, and the apparatus can be moved at will.

The ten cycle calling signal and the twelve cycle disconnecting signal are transmitted as a modulation of the twenty or thirty kilocycle sending wave. Instead of the disconnecting signal, the plunger 44 may be pulled by a spring against the action of coil 48. When the ten cycle signal ceases, the plunger is pulled out and the filament circuit opened. In this latter case, coil 48 and condenser C may be omitted.

Having described my invention, what I believe to be new and desire to secure and protect by Letters Patent of the United States is:-

l. A signaling system comprising a transmission line, means for superposing a modulated carrier current on said line, and a radio transmitting set operatively associated with said line to broadcast signals transmitted by the carrier and normally in inoperative condition, said set comprising means for receiving said carrier current, means controlled by said carrier current for automatically putting said transmitting set into operative condition and causing it to send out radio frequency waves, and means for modulating the radio frequency waves in accordance with said modulated carrier.

2. A signaling system comprising a transmission line, means for superposing a modulated carrier carrier for putting said sets into operative condition and automatically generating and sending out radio frequency waves, and means for modulating the radio frequency waves in accordance with said modulated carrier.

3. A signaling system comprising a transmission line having a modulated carrier current superposed therewith, means within said radio sets automatically actuated by the carrier current to put the sets in operative condition to broadcast locally, said radio sets comprising means for retransmitting modulations of said carrier at radio frequencies.

4. A radio signaling system comprising a plurality of radio broadcasting sets situated at intervals, a transmission line associated with said radio sets and having signal-1nodulated carrier currents impressed thereon, means within each of said radio sets responsive to the carrier currents to put the sets in operative condition, and means for modulating the outputs of said radio sets in accordance with the signals.

5. A signaling system comprising a plurality of radio transmitting sets situated at intervals, a transmission line associated with said transmitters and mitters operable by the carrier current for putting the sets in communicative relation with said transmission line, and means whereby a signal transmitted by the carrier current over said line in operating condition, and means to modulate the output of said set in accordance with the modulated carrie current received.

g magnetic waves, said apparatus being responsive to a given carrier current superposed upon the transmission line, and means to modulate the output of the transmitting set in accordance with the modulated carrier current received.

quency, said means being responsive to a modulated carrier current of a given frequency superposed upon the transmission line, and means for modulating the output of the transmitter in accordance with the modulated carrier current received.

9. In a signaling system, a plurality of radio broadcast transmitters, a transmission line multinly associated with said transmitters, means carrier current upon current for putting the same into communicative relation with the transmission line, and means Within the transmitters for modulating their outputs in accordance with the modulated carrier current, whereby the carrier current signals can be sent out from all of said radio transmitters simultaneously.

10. A signaling system comprising a plurality of low powered radio transmitting sets each having a limited broadcast area, and situated at intervals along a transmission line and operatively associated therewith. means within. each of said sets whereby the same can be rendered operative or inoperative for transmitting purposes, said means being responsive to a modulated carrier outputs of said sets in accordance with the modulated carrier current to simultaneously broadcast from said sets the signals carried by the modulated carrier.

11. A signaling system comprising a transmission line having a carrier current superposed thereon, an inductance in series with the line, a transmitting set having a radio frequency waves, and means the radio frequency waves in accordance with signals carried by the carrier current.

12. The method of transmitting signals which consists in impressing a carrier current upon a transmission line carrying direct or low frequency currents, modulating said carrier in ac- ALEXANDER N YMAN

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