US3274606A - Antenna system - Google Patents

Description

p 1966 G. A. BONADIO 3,274,606

ANTENNA SYSTEM Filed Jan. 15, 1964 67 RECEIVER AND/ OR TRANSMITTER INVENTOR.

GEORGE A.BONAD|O.

ATTO RN E 1 United States Patent 3,274,606 ANTENNA SYSTEM George A. Bonatlio, 373 East Ave, Watertown, N.Y. Filed Jan. 15, 1964, Ser. No. 337,812 2 Claims. (Cl. 343854) This invention relates to antenna systems for radio and television and more particularly to a relatively small sized, broad band antenna system, conspicuous for its ease of matching for overall efiiciency, wherein the directional characteristics of the antenna may be instantly shifted by an angle of ninety degrees.

Because of the directional characteristics generally in. herent in antenna systems, it has been the practice to physically or mechanically rotate the antenna so that its receiving and transmitting directional pattern may be aligned for best results in communication with a particular distant station. It is well known that radio signals have a tendency to fade due to atmospheric conditions, such as changes in the condition of the ionosphere. I have discovered that by instantaneously shifting the directional characteristics of the antenna system, reception or transmission of signals from or to a specific distant station that have faded while the radiation pattern and polarization of the antenna system is directed in one direction of azimuth may be restored upon shifting the direction of the radiation pattern and polarization to a different azimuth. The present art of physically rotating the antenna system to change the direction of its radiation pattern, by means heretoforeknown, is a slow operation, and restoration of reception of a faded signal from a given source by physical rotation of the antenna system normally is ineffective; but even when it is, this results in loss of signals during the period consumed by the rotation operation. I have discovered that generally deep fading is a rnulti-path net neutralization of full strength signals. A sudden change of the azimuth polarization of an antenna, at such a deep fade, usually shows only a slight fade in the other mode. Such a condition may reverse several times per minute.

The present invention is directed to an antenna system, which may be of the umbrella or centrally supported type, or of the spider web, or parimetrally suspended type, in which four generally horizontal conductors, of equal length, extend radially from the central lead-in connections, at precisely right angles to one another. Two adjacent conductors are connected to one lead-in, while the other two adjacent conductors are connected to the other lead-in. Each pair of conductors thusly connected to a lead-in constitute an electrical cone in effect, the length or altitude of which is approximately equal to the average diameter, or spacing of the two conductors. By disposing the conductors radially at angles of exactly 90 degrees, the lowest length-to-average-diameter-ratio of any two adjacent conductors is achieved; and the diflicult to tune out extremes of wide variations in resistance and reactance with changes of operating frequency, a most serious problem with present broadband systems, are reduced to their minimum limits, so that the system may operate at maximum efiiciency and respond to a wide range of frequencies, using conventional tuning equipment of modest values.

By so arranging the four radiating conductors at right angles, I am enabled by suitable switching means, located at the center of the four conductors, to shift the leads from adjacent pairs of conductors, having a radiation pattern in one direction, to adjacent pairs of conductors, having a radiation pattern in a direction 90 degrees therefrom, while maintaining the electrical loading constants of the antenna system Without apparent change. Thus, by switching, the radiation pattern can be shifted 90 de- Patented Sept. 20, 1966 grees instantaneously, and at will, without complications to the attached receiver or transmitter circuits. Since the radiation pattern of the four conductors, with adjacent pairs connected to the lead in wires, as set forth, is symmetrical about one axis, the shift resulting from the switching referred to, is effective to shift the pattern from, for example, a north and south direction to an east and west direction.

The invention further has to do with the remote control of the switching means, by power transmitted through the lead-in wires, in a manner such that no interference with radio transmission, or reception, results.

The above and other novel features of the invention will appear more fully hereinafter from the following detailed description when taken in conjunction with the accompanying drawing. It is expressly understood that the drawings are employed for purposes of illustration only and are not designed as a definition of the limits of the invention, reference being had for this purpose to the appended claims.

In the drawing wherein like reference characters indicate like parts:

FIGURE 1 is a diagrammatic illustration of one form of antenna system, contemplated by the invention, together with switching control effected through the leadin transmission line;

FIGURE 2 is a diagrammatic illustration of the antenna system when switched to one position; and

FIGURE 3 is a diagrammatic illustration of the same antenna system when switched to the alternate position to rotate the radiation pattern thereof 90 degrees.

Referring to the drawing, there is shown diagrammatically an antenna system comprising four antenna wires 20, 22, and 24 and 26 of equal length, each radiating from the vertical axis A of the system, in directions precisely 90 degrees from one another. Each antenna wire may terminate at its outer end at an insulator 28, and be supported from a mast 29. Each antenna wire at its inner end terminates in a connection to a solenoid actuated double-pole double-throw switch indicated generally at 30. Such switches may have stationary contacts 32, 34, 36 and 38, each connected to the respective antenna wires 20, 22, 24 and 26, and a rotary switching commutator having arcuate conductors or switching segments 4t) and 42 adapted to cooperate with contacts 32, 34, 36 and 38. The switching commutator will rotate through an angle of 90 whereby to effect connections between contacts 32 and 38, and contacts 34 and 36, or connections between contacts 32 and 34, and contacts 36 and 38. The switching segments 40 and 42 may be carried on an insulating rotor 44 having a shaft 45. The rotor is rotated to the position shown by a return spring 52, acting on a lever 54, which operates a crank arm 55, and is rotated to the other position by energization of the solenoid 56.

Leads 60 and 62 connect with the segment 40 and 42 and to one end of the transmission line 64, the other end of the transmission line being inductively, or otherwise coupled, as at 66, to a receiver or transmitter 67, through identical capacitances 63 and 65, which have very low reactances for the lowest operating frequencies. The transmission line is also employed to transmit necessary power to the solenoid 56, to actuate the switch rotor 44, from the position shown, to the alternate position. In order to utilize the transmission line for this purpose, ordinary 60 cycle alternating current, at a suitable voltage to actuate the relay, is supplied by a transformer 68, the primary circuit 70 of which has an on and off switch 72 shunted by a capacitance 69 and resistor 71 to dampen out transients. The secondary 73 is connected to a capacitance 75, and to each of the transmission line conductors 74 and 76 through high and low frequency chokes 78 and 80, the high frequency chokes being of a value to be effective to block the highest radio frequency to be used, and the low frequency chokes being of a value to be effective to block the lowest radio frequency to be used in transmission and reception. The transformer core is preferably grounded as at 82, and the secondary terminals are each grounded as at 85 through capacitances 84 and 86.

Power to operate the solenoid is taken from each of the conductors 74 and 76 through similar high radio frequency chokes 78 and 80, the solenoid being connected in shunt with a capacitance 88.

It will be seen from the foregoing that when conductors 20 and 26 are connected together, and conductors 22 and 24 are connected together, as in FIGURE 1 and FIGURE 2, radiation patterns symmetrical about an axis bisecting the angle between conductors 20 and 22, and conductors 24 and 26 will result. When the switch is shifted to the position shown in FIGURE 3, the radiation patterns heretofore referred to are shifted 90 degrees. Since all four conductors 20, 22 and 24 and 26 are of like length, and are physically at angles of 90 degrees to adjacent conductors, the effect of the antenna system, in so far as the transmitter or receiver connected thereto is concerned, is not changed by such switching. The sole effect of such switching is to shift the radiation pattern by precisely 90 degrees in azimuth. Thus during transmission, should reports of fading be received from the distant station receiving the signal, the radiation pattern may be instantly shifted to ascertain whether alteration of the radiation pattern will result in the transmission of signals to such station of sufficient strength, and thus overcome the fading resulting from the use of the other mode of azimuth polarization of the radiation pattern. It will be understood that by shifting the radiation pattern, the wave azimuth polarization of the energy transmitted and reaching the distant station is varied so that the effect of the ionosphere in reflecting the signal is changed, and thus the conditions causing the fading may thus be temporarily eliminated. With rapid fading, it has been possible, with applicants system, to switch from one pattern to the other as fading is reported, and thereby maintain contact with the distant station with adequate signal strength.

While utilization of the wave pattern shift during transmission must of necessity depend upon reports from the distant receiving station as to fading, the system may be used during reception from the distant station instantaneously by the receiving operator. When the signals from a distant station tend to fade, it is found that, by instant shifting to the alternate radiation pattern, such signals will be found to have adequate strength for contlnuous reception; and should the signals tend to fade during use of the alternate pattern, instantaneous switchng to the original pattern will usually be found to result in reception of the signals, with adequate strength, the previous fading having disappeared due to some change in the atmospheric or ionospheric conditions in the meanrme.

Thus it has been found possible in nearly all instances to retain continuous contact with a given transmitting station during conditions causing fading, by instantaneous switching from one pattern to the other, as soon as the tendency to fade in the one pattern is detected by the operator at the receiving end. However, if the receiver operator has a similar antenna system, he can accomplish alone the fading correction from minute to minute. Thus, two stations using this system can continue through otherwise troublesome conditions of fading.

In normal operation, before establishing contact with a distant station, the antenna system is resonated and loaded. Then relay mode of FIGURE 2 or FIGURE 3, hereinafter referred to as A or B is chosen by observing which mode delivers the higher level of signal strength to the receiver signal strength meter. A difference of 4 3 to 8 decibels frequently is available. Rarely differences of 10 decibels Will hold between modes. Occasionally no difference can be noticed between modes A and B. The differences in the received state is duplicated in transmitting state between two stations, at any momentary given set of conditions.

In practice it has been found that employing an antenna of the spider web type utilizing #8 B and S gage aluminum conductors each of a length of 58 feet, and approximately 30 high and employing a 180 to 200 ohm transmission line of #8 B and S gage aluminum wire 75' long, a wide range of wavelengths may be accommodated, from 2 meters to 200 meters (150 to 1,500 megacycles) with good response throughout the range. A tuner operating Q (Quality factor) of approximately 3 is excellent. Series tuning is favored for transmission line impedance appearances of less than 200 ohms. A tight link transfers best. Capacitors 63, 65, 75, 84, 86 and 88 may be 0.1 mfd. ceramic, at 500 volt rating. While the spider web type of antenna has been illustrated, an umbrella type antenna, using substantially larger diameter conductors and transmission line, with the four radial conductors approximately 25 feet long and having increased height approximating 60 feet, will be found to be equally effective, even for wavelengths twenty times as long as each radial conductor.

While, for illustrative purposes, a rotating commutator type switch has been shown, any solenoid actuated doublepole double-throw switch may be utilized, and in practice, one using mercury contacts has been found effective. The type of switch illustrated provides for exact uniforrnity in length of connections in respect to all conductors, so that the antenna will be assured of having the same characteristics in either switch position.

However, with exacting care, any heavy duty doublepole double-throw switch may be employed, and such leads as are necessary must be balanced so that the antenna has the same exact characteristics, irrespective of the switching position. The necessity for exact balancing is critical, especially at the shorter wavelengths otherwise the currents flowing in each of the four antenna conductors Will not be substantially equal, and the tuning problems will be exaggerated.

An anticipated problem of balancing modes A and B because of buildings and feeders under and near the elements has not materialized in practice; but a deviation of as little as 1 from the 90 configuration does produce an annoying imbalance between modes A and B. Because of its cumulative ratio, a radial imbalance of 2 usually results in a change of the load upon the transmitter to such a degree upon switching as to be intolerable.

While a single form of the invention has been illustrated and described, it is to be understood that the invention is not limited thereto. As various changes in the construction and arrangement may be made without departing from the spirit of the invention, as will be apparent to those skilled in the art, reference will be had to the appended claims for a definition of the limits of the invention.

What is claimed is:

1. An antenna system for radio transmission and reception comprising a generally horizontal system consisting of four single filamentary conductors of equal length extending radially and generally horizontal at horizontal angles of 90 degrees from one another from a central area and in alignment with a common center in said area, each of said conductors being insulated from one another and having their central area inner ends equally spaced from the common center, a double-pole double-throw two position switch disposed within the central area, said switch having four contacts equally spaced around a circle concentric with the common center and having one contact connected to a lead-in of a transmission line, and connected at all times to the inner end of a first one of said conductors, and another contact connected to a second lead-in of a transmission line, and connected at all times to the inner end of a second one of said conductors extending in the opposite direction to said first conductor, and the other two contacts connected to the inner ends of the two intermediate conductors respectively whereby in one position or the other of said switch one of said intermediate conductors is connected to either of said first or said second conductor, when the other of said intermediate conductors is connected to either the second or said first conductor, where by the radiation pattern of said antenna may be substantially instantly shifted exactly 90 degrees by actuation of said switch from one position to the other without altering the constants of the antenna system.

2. A system in accordance with claim 1, wherein the switch is solenoid actuated by remote control utilizing the two lead-ins of the transmission line.

References Cited by the Examiner UNITED STATES PATENTS HERMAN KARL SAALBACH, Primary Examiner. R. F. HUNT, JR., E. LIEBERMAN, Assistant Examiners.

Claims (1)

1. AN ANTENNA SYSTEM FOR RADIO TRANSMISSION AND RECEPTION COMPRISING A GENERALLY HORIZONTAL SYSTEM CONSISTING OF FOUR SINGLE FILAMENTARY CONDUCTORS OF EQUAL LENGTH EXTENDING RADIALLY AND GENERALLY HORIZONTAL AT HORIZONTAL ANGLES OF 90 DEGREES FROM ONE ANOTHER FROM A CENTRAL AREA AND IN ALIGNMENT WITH A COMMON CENTER IN SAID AREA, EACH OF SAID CONDUCTORS BEING INSULATED FROM AND ANOTHER AND HAVING THEIR CENTRAL AREA INNER ENDS EQUALLY SPACED FROM THE COMMON CENTER, A DOUBLE-POLE DOUBLE-THROW TWO POSITION SWITCH DISPOSED WITHIN THE CENTRAL AREA, AND SWITCH HAVING FOUR CONTACTS EQUALLY SPACED AROUND A CIRCLE CONCENTRIC WITH THE COMMON CENTER AND HAVING ONE CONTACT CONNECTED TO A LEAD-IN OF A TRANSMISSION LINE, AND CONNECTED AT ALL TIMES TO THE INNER END OF A FIRST ONE OF SAID CONDUCTORS, AND ANOTHER CONTACT CONNECTED TO A SECOND LEAD-IN OF A TRANSMISSION LINE, AND CONNECTED AT ALL TIMES TO THE INNER END OF A SECOND ONE OF SAID CONDUCTORS EXTENDING IN THE OPPOSITE DIRECTION TO SAID FIRST CONDUCTOR, AND THE OTHER TWO CONTACTS CONNECTED TO THE INNER ENDS OF TWO INTERMEDIATE CONDUC-

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