US1471406A - Radiotelegraphy - Google Patents

Description

Oct. 23 1923. 1,471,406

F. S. M CULLOUGH RADIOTELEGRAPHY Filed July 25 1919 4 Sheets-Sheet 1 Bx WM W HTTaR/VEYJ.

Oct. 23, 1923. 1,471,406

F. s. MCCULLOUGH RADIOTELEGRAPHY Filed July 25 1919 4 Sheets-Sheet 2 1 "L24 nnmmygl; W

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Oct. 23 1923. 1,471,406

F. s. MOCULLOUGH RADIOTELEGRAPHY Filed July 25 1919 4 Sheets-Sheet 4 l/vl/awroe: 3 M 4? AW 5 TM 71.4161 1 I. 14 770195X:

Patented a. is, 1923.

UNITED STATES PATENT OFFICE.

FREDERICK S. KOOULLOUGH, OF CLEVELAND, OHIO, ASSIGNOB TO GLENN L. MARTIN, OF CLEVELAND, OHIO.

RADIOTELEGRAPHY Application filed July 25, 1919. Serial No. 813,181.

To all whom it may concern:

Be it known that I, FREDERICK S. MOCUL- LOUGH, a citizen of the United States, resident of Cleveland, county of Cuyahoga, and

State of Ohio, have invented new and useful Improvements in Radiotelegraphy, which the following is a specification, the principle of the invention beingherein explained and the best mode in which I have contemplated applying that principle, so as to distinguish it from other inventions.

My invention relates to systems of radio telegraphy and more particularly to systems for determining the direction of distant transmitting stations. 1

In the radio directional systems hitherto employed, the incoming electromagnetic waves have been received on antennae having special forms. generally in the shape of a closed loop, and the strength of the signals, with whatever form of detector that has been used, has been determined by the loudness of the sounds received in a tele phone. This audible means of determining the direction of incoming radiant energy is more or less indefinite under any circumstances, and fails altogether where there are loud extraneous noises, as, for instance, on an aeroplane.

In view of these considerations, I have invented a system by which the strength of the received signals is shown visually, and the direction of maximum or minimum effect of the received electromagnetic waves, and hence the direction of the transmitting station, can be determined with great accuracy, and in spite of any amount of noise in the vicinity.

My invention also makes it easy to determine the direction of two or more distant transmitting stations simultaneously, and to determine the position of a moving receiving station, such as that on an aircraft or a boat, at any moment. The annexed drawings and the following description set forth in detail certain means embodying my invention, the disclosed means, however, constituting but one of various mechanical forms in which the principle of the invention may be employed.

In the accompanying drawings, which are largely diagrammatical, Figure 1 shows one form of my radio directional apparatus with a cathode-ray-tube indicating means.

j F igure. 3 shows another modification of my invention, having a receiving antenna with a large loop, with a crystal detector and a cathode-ray tube.

Figure 4 shows a modification of my system, with means for amplifying the received osgillations, and with a sensitive galvanome r.

Figure 5 shows a modification of my system with a 100 antenna, means for amplifying the received oscillations, and a galvanometer.

Figure 6 shows a modified form of my system, with two directional loop antennae.

Figure 7 shows a modification of my system, with two directional tube units.

Figure 8 shows a modified form of my invention for determining the direction of two transmitting stations simultaneously.

Figure 9 shows, diagrammatically, a method for determining the instantaneous position of a moving body, such as an aircraft or boat.

Figure 10 shows a modified form of my invention for determining the direction of three transmitting stations simultaneously.

In Figure 1, l is a cathode-ray tube; 2

.is an induction or spark coil: 3 is a cathode,

and 4; is an anode, both inside the tube and connected with the spark coil; rays are iven oil by the cathode, and are interce ted y the diaphragm 5, which p'ermits only a beam or pencil of rays to pass through a small opening; 6 is a surface, such as a mica screen or otherfluorescent surface, on which the beam of cathode rays impinges, making a bright spot when the beam is steady, and tracing a line of light when the beam moves. This screen is preferably transparent or translucent, so that the spot or line of light is visible on either side. This screen may have a scale marked on it, to

measure the line of light. 7 and 8 are electrodes inside the tube and connected with the radio directional system; 9 and 10 are positions of the beam of cathode rays under the influence of electrodes 7 and 8; 11 is an evacuated tube; 12 is a directional coil inside the evacuated tube; 13 is another directional coil inductively related to coil 12, with its axis parallel to, or coincident with that of 12, and also contained in the evacuated tube; 14 is a heated filament, or other source of ionization, also contained in the evacuated tube; 1:") is a variable condenser crmneet'ed with coils 12 and l3; 1G is a variable condenser connected with coil 13 and tian'ent 14; l i a batter v for hea ing lilament 14; 18 is a variable rcsistance; and 19 is a batterv for energizing'the circuit containing the filament 14, coil 12 and the electrodes 7 and 8. 20 is a mirror, which refleets the spot or line of light from the surface or screen 6 to a scale 21, the line of light on the scale being shown at 22.

In Figure 1/1, (3 is an end view of the screen in the cathode-ray tube, on which-is shown a line of light, 23, formed when the beam of rays moves.

In .Figure 2, 1 to 10, inclusive, are elements similar to those having the same numbers in Figure 1; 24 is a closed loop antenna; 25 is a variable inductance; and 2G is a variable condenser. The loop should have such characteristics and the electrical quantities of the circuits should have such values as Will give the best results in each case. 27 is a filament; 28 is a grid and 29 is a plate, all three contained in a vacuum tube 30. 31 is the battery for the plate circuit; 32. is the battery for heating the filament 27; and is a variable resistance in the filament circuit.

In Figure 3, 1 to 10, inclusive, are elements similar to those having the same num bers in Figures 1 and 2. 34 is a large directional antenna; 35 is the primary of an oscillation transformer, of which 36 is the secondary; 37 is a variable condenser in the secondary receiving circuit; 38. as shown, is a detector of the crystal type, but it may be a detector of any other suitable kind; 39 is acondenser.

In Figures 1, 2 and 3, instead of having the screen 6, the cathode rays may impinge upon the end surface of the tube as shown in Figure 7.

In Figure 4, 40 is an evacuated tube, 41 is a directional coil inside the tube, of the type shown in Figure 1; 42'is another directional coil inductively related to coil 41. with-its axis parallel to, or coincident with that of 41, and also contained in the tube; 43 is a filament which can be heated, or other source of ionization: 44 is a variable condenser connected with coils 41 and 42; 45 is a variable condenser connected with coil 42 and filament 43; 46 is a battery for heating filament 43; 47 is a variable resistance for regulating the current in filament 43; 48 is a battery for energizing the circuit containing coil 41, filament 43 and the primary 49, of a transformer. 50 is the secondary of this transformer. 51 and 52 are coils and 53 is. a filament, or other source'of ionization, contained in the tube 40, and similar, respectively, to coils 41 and 42 and filament 43. 54 and are variable condensers. 56 is a battery and 57 a variable resistance, in circuit with filament 53. 58 is a battery for energizing the circuit containing coil 51, filament .53, and galvanon'ieter 59, which latter indicates the strength of the received signals after amplification by the above-described system.

In Figure 5, 60 is a directional loop antenna; (ll is a variable condenser and 62 is a variable inductance. 63 is a filament; (.34 is a grid; and 65 is a plate, all three contained in a vacuum tube or bulb; 66 is a battery for heating the filament 21; 67 is resistance tor regulating the current passing through the filament; 68 is a battery for supplying current to the plate circuit, which also comprises the primary, 69, of a transformer. the secondary of which is 70. 71 is a filament; 72 is a grid, and 73 a plate; all three contained ina vacuum tube. 74 is a battery for heating the filament 71, and 75 is a variable resistance for regulating the current through the filament. 76 is a battery in circuit with the filament 71, the'plate 73, and the galvanometer 77, which latter indicates the strength of the received signals after amplification by the above receiving system.

In Figure 6, 80 and 81 represent directional loop antennae, whose position relative to each other is adjustable, but which are here shown at right angles to each other. Pre'autions should be taken to avoid mutual interference. ceiving apparatus such, for instance, as shown in Figures 1 to 5, but the details of which are omitted here for the sake of convenience. 84 and 85 are sensitive galvanometers of any suitable type. 86 and '87 are mirrors attached to the movin or indicating part of the galvanometers, 86 being shown with a horizontal suspension and 87 with a vertical suspension, for purposes of illustration. 88 is a light, or source of illumination, of any convenient kind, the reflections of which from the galvanometer mirrors indicate their movements. 89 is a screen on which the reflections of the light 88 are thrown. 90 and-91 are scales marked on the screen and here shown at right angles to each other: but the angle between these scales may be any found most suitable. 92 and 93 are spots of light, being the reflections of the light 88 from he galvanometer mirrors. Vhen bot-h mirrors are in their normal positions, that is to say, when no current is passing through the galvanometers, the spots of light will beat the zero point at the intersection of the scales, but when current flows through one or both 82 and 83 represent radio re-' galvanometers, the spot of light correspondmg to that galvanometer, will move away from the zero point along its respective scale. In this figure, the spot of light 92 from the galvanometer mirror 86 is shown at some distance from the zero point, While the spot-of light 93 from the galvanometer mirror 87 is shown at the zero point.

In Figure 7, 94 and 95 are directional tube units on my system; 96 is an element, such as a rod, connecting these two tubes, by which the can be turned in any desired direction. he tubes can be set at any desired angle with each other, but are here.

shown at right angles. They should be far enough apart to avoid mutual interference. 97 and 98 represent radio receivin apparatus such, for instance, as shown in igures 1 and 4. 99, 100,101 and 102 are electrodes in a cathode-ray tube connected in pairs with the radio receiving apparatus 97 and 98. 103 is an induction or spark coil. 104 is a cathode ra tube. 105 is an anode and 106 is a catho e in the tube and connected with the spark coil. 107 is a diaphragm with a small opening which permits a beam or pencil of cathode rays to pass through. 108 rep-resents the cathode rays which have passed through the diaphragm opening. 109 is the end surface of the tube, composed of such material as will show a spot or line of light where thebeam of cathode rays impinges. It may also be a screen, composed of mica or some other suitable material, as shown in Figures 1, 2 and 3. 110 is a line of light produced by the movement of the beam of cathode rays. light produced when the beam of rays is at rest in its normal position. The varying electrification of the electrodes 99, 100, 101 and 102, caused by the varying amounts of radiant energy effectively received by the directional tubes 94 and 95, cause the beam of cathode-rays to move in one direction or the other from its normal position and so vary the form and dimensions of the lines of light on the screen 109. r

In Figure 8, 112 and 113 are directional loop antennae which can be moved independently of each other, and which are far enough apart to prevent disturbing mutual interference. 114 and 115 represent radio receiving apparatus connected, respectively, with the directional loops 112 and 113, and which may be of any suitable kind such, for instance, as shown in Figures 1 to 5 inclusive. 116 and 117 are sensitive galvonometers of any suitable type. 118 and 119 are mirrors attached to the needles or other moving parts of the galvanometers. and suspended so that spots of light reflected from them will travel in different paths when thrown on the screen 121. 120 is a light or source of illumination of any suitable kind, which is reflected from the galvanometer 111 is the spot of mirrors onto the screen 121. 122 and 123 represent lines of light caused by the rapid movement to and fro of the galvanometer mirrors 118 and 119, respectively. This movement of the galvanometer mirrors is caused by the electromagnetic waves received on the loop antennae 112 and 113, respectively, as modified by the radio receiving apparatus 114 and 115. I may also use types of galvanometers such as those used in Figure 6, which have a steady deflection instead of a rapid vibration of the movable members.

In Figure 9, M and N represent transmitting stations whose position on the chart or map is fixed. A and B re resent different positions of a movable receiving station on an aircraft, or boat, or other moving body. 145 and 146 are directional loop antennae, directional tubes or other apparatus which receives varying amounts of radiant energy depending upon its direction with reference to the transmitting station. When the moving body is in position A, these direction finders are turned until one gets the maximum cited; (or the minimum efiect), from one transmitting station and the other gets the maximum effect (or the minimum effect) from the second transmitting station. The direction of the transmitting stations from the movin body is thus determined at any instant an the exact position of the moving body can be at once fixed on the. chart or map if the compass bearing of at least one of the transmitting stations is also known. After any interval of time, observations can again be made,-and a second position of the moving body, such as at B, can be fixed. The course A-B and the distance traveled can then be readily ascertained.

In cases where neitherthe magnetic nor gyroscopic compass can be relied upon, and where the heavenly bodies are obscured so that it is impossible to find the compass bearing of either of two transmitting stations, the position of the moving body can nevertheless be determined by getting the direction of a third transmitting station, such as P, whose position on the map is fixed. The direction of P is determined by means of a third direction finder, such as 147, similar to 145 and 146, which is turned until the maximum effect (or the minimum efiect) is obtained from station I, and the latters direction is then noted simultaneously with the directions of the other two stations M and N. The position of the receiving station can then be found by calculation or with suitable instruments. To ascertain conveniently and quickly the position of the receiving station on the map or chart, suitable mathematical tables and mechanical aids can be used.

Figure 10 shows a system for obtaining avoid disturbing mutual interference.

' the directions of three transmitting stations simultaneously. 124, 125 and 126 are directional tubes, but there mayalso be used directional loop antennae, or other direction finders which can be moved independently of each other and are far enough apart t 12 128 and 129 represent radio receiving apparatus of any suitable type, such as shown, for instance, in Figures 1 to 5, inclusive. 130,- 131 and 132 are sensitive galvanometers of any suitable type. 133, 134 and 135 are mirrors attached to the movable indicating parts of these galvanometers, respectively. 136, 137 and 138 are lights of any suitable type, to berefiected from the galvanometer IIllITOIS onto the screens 139, 140 and 141, respectively. 142, 143 and 144 are lines of light produced by the movement of the galvanometer mirrors, the extent of the deflection of the galvanometer mirrors being shown byscales on the screens. Instead of a line of light as here shown, caused by the rapid to and fro motion of the galvanometer needle or reed or other moving part, there may be a spot of light in a steady position produced by the steady deflection of the galvanometer mirror, where such a type of galvanometer is used.

In the forms of'my invention shown in Figures 1, 4, 7 and 10, I employ directional receiving means which I have described fully in my co-pending application, Serial No. 308,978, filed July 7, 1919. In Figure 1 there is shown aslngle unit, in Figure 4 there are two units in the same evacuated tube, in Figure 7 there are shown two separate tubes, each of which may contain one or more units, and in Figure 10 there are shown three separate tubes, each of which may contain one or more units. I have found that when the lanes of the coils in the tubes are in the dlrection of the transmitting station, or, in other words, when the axes of the coils are at right angles to a line joining the transmitting and receiving stations, the received signals are at a maximum. The tubes with the coils are therefore turned until the maximum 'effects are observed on the indicating apparatus, and the direction of the transmitting station is at once determined. Besides acting as'direction finders, my tubes, with the accompanying apparatus, also perform the function of electrical wave or oscillation detectors.

In the forms of my invention shown in Figures 1, 2 and 3, the variations of the received current change the electrical condition of the terminals 7 and 8, and thereby cause deflections of the pencil or beam of cathode rayspassing along the tube 1, through the dia hragm 5.

The rapidly-a ternating variations in the electrification of the terminals 7 and 8 are followed by movements of the pencil of rays. At the end of the tube the pencil of rays falls upon a mica screen or some other suitable surface, and when at rest, it makes a spot of light there. When under the influence of the alternating electrification of the terminals 7 and 8, the pencil or beam of rays moves to and fro, and traces a line of light on the screen. The greater the electrification of the terminals, the greater the amplitude of the movements of the beam of Figure 7, I employ two direction-finding tubes, which are independent of each other. The energy received by the directional coils in one of them, 94, acting through the rest of the apparatus, indicated at 97, varies the electrical condition of the electrodes 99 and 100, which are 180 degrees apart, and so changes the direction of thebeam of rays 108. When these changes follow each other rapidly, a line of light appears on the screen. The energy received by the directional coils in the other tube, 95, acting through the rest of the radio apparatus indicated at 98, varies the electrical condition of the electrodes 101 and 102, which are 180 degrees apart, and 90 degrees from electrodes 99 and 100. These variations in electrodes 101 and 102 deflect the beam of rays at right angles to the deflections caused by electrodes 99 and 100. The resultant dlrection of the beam of rays will depend upon the relative strength of the electrification of the electrodes, and so will the form and dimensions of the figure of light traced on the screen 109. When the electrification of one pair of electrodes, for instance, 99 and 100, is at a maximum, and the electrification of the other pair, 101 and 102, is at a minimum, the beam of rays will vibrate in a plane through the-electrodes 99 and 100, and a line of light, such as shown at 110, will be traced on the screen. This state of affairs will indicate that the tube 9 1 is receiving the maximum effect from the 'incomin radiant energ and the tube 95 the mimmum effect. s these tubes have been set so that the axes of their enclosed coils are at right angles to each other, the direction of the distant transmitting station is at once determined. By this system, any deviation from the maximum or minimum position than when only one tube is used.

Instead 'of using two of m directional tubes with my cathode-ray indicator, I may employ two directional loop antennae, or two large directional antennae, in a similar manner to that shown with one directional loop and one large directional antenna, in Figures 2 and 3, respectively.

In the forms of my invention shown in Figures 4, 5, 6 and 8, sensitive galvanometers indicate the strength of the received signals. In some cases, it is preferable to amplify the received oscillations in order to cause the galvanometers to show great enough deflections, and I therefore provide amplifyingzmeans, as shown. In the form shown in igure 4, the amplification is secured by two units of my directional-tube system, fully described in my said co-pending application, and in the form shown in Figure 5, the amplification is obtained by means of an ordinary vacuum tube amphfier. With some forms of galvanometer, such, for instance, as those having a vibrating reed capable of being tuned to a definite fre uency, amplification Is not essential, and nee not be employed.

In the form of my invention shown in Figure 6, I employ two directional loops at right angles to each other, so that when one is in the position for maximum effect, the other is in the position for minimum effect. M indicating means consists of sensitive galvanometers, one of which is actuated, through suitable receivin apparatus, by the effective energy received y one of the loops, and the other one is actuated by the effective energy received by the other loop. For purposes of convenience I use a single screen for receiving the spots of light reflected from both lvanometer mirrors, and I dispose the mirrors so that the movements of the beams of light from them are in different planes, and can be clearl distinguished on the screen. I have here s own the spots of light moving at right angles to each other, but they may make any convenient angle. Instead of the directional loops I may use my direction-findin tubes arranged as shown in Figure 7. fie arrangement shown in Figure 6 is particularly useful for the purpose of determining the direction of a single transmitting station more accurate- 1 than can be done with a single loop, but the loops can be adjustable so as to make any angle with each other and can then be used to determine the direction of two transmitting stations simultaneously, provided proper precautions are taken to avoid mutual interference between the loops.

In Figure 8 is shown a modification of my system, embodying a preferable arrangement for receiving electromagnetic waves from two transmitting stations simultaneously and determining their res ective directions. I use two separate directional loops, which can be adjusted independently of each other.

Each one actuates a sensitive galvanometer or other suitable indicating apparatus, and the reflected light from these two galvanometer mirrors is thrown on the same screen. The galvanometer mirrors are so suspended that the beams of light from them move in different planes, and are shown in different lines on the screen. I may employ a form of galvanometer in which the light is reflected rom a member which vibrates under the influence of the incoming currents or oscillations, so that the beam of light traces a line upon the screen, the len h of this line indicating the strength of t e received current, and hence the effective energ received in any position of the directiona loop. Each receiving unit should preferably be tuned to the wave length of the transmitting station, and where a tuned vibrating reed is used in the galvanometer, this reed should be tuned to the spark or group frequency of its correspondlng transmitting station. The loops s ould also be placed so as to avoid mutual interference with each other. In operatin this system, the loops should be turned unti the maximum deflection for each unit is observed on the screen. At this instant, the direction of the respective loops is noted, and, if necessary, transferred to a chart or map, and the position of the receivin station can be determined, as shown in igure 9, provided the compass bearing of at least one of the transmitting stations is also determined at the same time by the direction finder. If, however, at the receiving station the magnetic compass and the gyroscopic compass or any other means of showing the compass bearing are not operative, and if the heavenly bodies are invisible, it will be necessary to know the direction of a third transmitting station in order to fix the position of the receiving station.

In Figure 10, I have shown the means for accomplishing this object. I there have three direction finding units, one for each of the transmitting stations. The direction finding member may be either one of my direction finding tubes, or a directional loop antenna, or any other suitable means. The indicat ing means may be either galvanometers, cathode-ray tubes, or other suitable means for showin the strength of the received energy visual y. Each receiving system is preferably tuned to the wave length of its corresponding transmitting station, and where a tuned indicating apparatus is employed, the latter is also tuned to the spark or group frequency of the corresponding transmitting station. The directional tubes or loops and other receiving apparatus are so arranged as to avoid mutual interference.

The dimensions and characteristics of the loops, coils and other apparatus, and the values of the electrical quantities of the various arts of my system are so chosen as to obtain the best results in each case. In general, I do not confine myself to the exact constructions and arrangements herein described, but I may also employ other means within the scope of my invention, but what I claim and'desire to secure by Letters Patent is:

1. In a radio receiving system, the combination with directional receiving means enclosed in an evacuated tube, of a visual indicator of the strength of the received signals.

2. In a system for receiving radiant en ergy, the combination with detecting and directional receiving means enclosed in an evacuated vessel, of visual means for indicating the strength of the received signals.

3. n a radio receiving system, the combination with a plurality of evacuated tubes containing directional receivingcoils, of visual means for indicating the effective radiant energy received on said coils.

4. A radio receiving system having two directionalreveiving units, each-of said units consisting of coils and a filament contained in an evacuated tube, the axes of the two sets of said coils being at right angles to each other.

Siglned b me, this 23rd. day of Jul 1919.. RE ERICK s. MoCULLO G

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