US1752864A - Antenna system - Google Patents

Description

April 1,1930. L. A. j rAYLoR ANTENfiA SYSTEM Filedju gl. 20, .1928

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H (D. Z 9 M H E m Patented Apr. 1, .1930

UNITED STATES PATENT OFFICE LAURENS A. TAYLOR, or scHnNEc'rAnY, NEW YORK, ASSIGNOR TOQENERAL ELECTRIC COMPANY, A CORPORATION .01 NEW YQRK ANTENNA SYSTEM 'Applicationfiled August 20, 1928. Serial No. 300,727.

My invention relates to antennae systems and more particularly. to an antenna system which is adapted for operation on short wave lengths. v V i Ithas for its purpose to provide a system of the type indicated which is adapted to radiate .large amounts of power at'short wave lengths and in which absorption losses in the ground are a minimum. More particularly my invention has for its purpose to provide an antenna system of simple construction which has the property of projecting the radiated wave into the higher strata of the atmosphere whereby it is efficiently transmitted to remote receivers and sufiers a minimum of loss due to absorption in the ground. Another object of the invention is to provide a system of the type indicated in which the parts towhich connections are frequently made, or which are frequently altered as for tuning purposes and the like are in close proximity to the earth, therebyto permit of convenient manipulation thereof. Still another purpose of the invention is to provide n an efficient antenna system which is of very simple and economical construction.

The novel features of my invention will be set forth with particularity in the appended claims. The invention itself, however, both tion will best be understoodby reference to the following description taken in connection with the accompanying drawing in which Fig. 1] represents an embodiment of my invention and Fig. 2 .represents a modification thereof;

Referring to Fig. 1 of the drawing, 1 rep resents a vertical radiating member having a length substantially equal to one-half ofthe length of the wave which is to be radiated.

This member is suspended from a suitable supporting member 2 which extends between towers 3 and 4. Located at the base of the radiating member 1 is an inductance coil 5 this coil having one terminal thereof connectas to its organization and method of opera-- ed to the midpoint ofa horizontal member 6. This horizontal member has a length which is less than one-half of the wavev length of the wave which is to be radiated and is located in proximity to and above the earth. The upper terminal of the coil may be connected to the lower end of the radiating member 1 by means of an adjustable tap 1 by means of which desired tuning of the antenna may be effected. 7 represents suitable high frequency transmitting apparatus, the output circuit of which is connected through suitable conductors, such as those of a transmission line'8, to points 9'and 10 upon-the coil 5, these points being at equal distance from a node of volt-age on the coil. The coil 5 has inductance such that it resonates with the capacity existing'between this coil and the horizontal conductor 6. Sufficient inductance is included in the section 15 of coil 5 to produce a very high potential at the point of connection with themember l'this potential serving to cause theradiating member 1 to oscillate. The oscillations of the radiating member .will have a voltage node at the midpoint thereof. The voltage wave of member 1 is represented by curve 11 and that on coil 5 and member 6 is represented by curves 12 and 13 respectively.

In Figure 2 I have shown a modification of my invention in which the member 6 'is replaced by a-condenser 14 connected in shunt with a portionof coil-5, the natural capacity between the earth and the antenna system being relied uponto cause the half wave length radiating member 1 to oscillate in response to oscillations produced in the circuit 5, 1 1. i I have found however that better results may be obtained by utilizingthe conductor 6 in that absorption losses in the ground are reduced and that the energy appears to be more completely radiatedas a space wave rather than as an earthwave. Further with the arrangement shown in Fig.1 the system opertance of the coil 5 from the ground. Thus this coil may be arranged at any convenient distance from the earth without substantially affecting the power radiated from the antenna.

In Figure 2 I have shown the radiating member as mounted above the coil 5 and connected thereto only by the natural capacity existing between the members. This arrangement permits of elevating the member 1 above the coil. An artificial capacity may be utilized to connect conductor 1 to coil 5 but it must be of construction such that it will withstand the high voltage existing at this point. I prefer, however, to connect the conductor 1 directly to the coil 5 as in Fig. 1 and insert suflicient inductance in the section 15 of the coil to produce a high voltage at the point of connection.

Whilethe effect of the conductor 6 upon the operation of the system is not fully understood I amof the opinion that it serves the purpose of an ordinary counterpoise and in addition thereto it appears to produce a certain amount of radiation which in combination with that produced by the member 1 tends to project the wave at a slight angle over the horizon thereby increasing the efi'ective transmission. Thus its operation is clearly distinct from that of a counterpoise in this respect. Further the length of the conductor 6, to be most efifective bears a definite relation to the wave length to be radiated. Its length extending from the lower terminal of coil 5 should be sufficiently less than one quarter of a wave length of the radiated Wave to permit the two conductors of the transmission line to be connected oppositely and symmetrically with respect to the node of voltage of the coil, and at the same time to permit these conductors to be connected to the coil at suflicient distances apart properly to terminate the transmission line. It must, of course, be of sufficient length to cause the vertical radiating member to be properly driven. I have found that much better results can be had with this arrangement than with any of the non-directive antennae of the prior art utilizing counterpoises.

My antenna has important advantages over any of the prior art in the manner in which it is assembled; The coil 5 and conductor 6 are in close proximity to the earth such that connections thereto, such as the transmission line connections and the connection of tap 1,

may be varied with convenience by one standing onthe ground; the former for the purpose of properly terminating the transmission llne and the latter for the purpose of tuning the antenna system. Since the radiating member 1 operates efficiently over a substantial range of wave lengths no adjustments within this range need be made other than those which can conveniently be made from the ground.

It will be noted that there is no direct connection between any part of the antenna system and ground. It is believed that in connection with the vertical radiating member of the type described, the absence of a ground connection reduces the amount of radiated energy which is expended in a ground wave and which is not efliciently transmitted to remote receivers, thereby causing an increased portion of the radiated energy to be expended in a space wave which traverses the upper strata of the atmosphere and which is not subjected to excessive absorption losses in the ground. This efiect is enhanced by use of the horizontal conductor 6 as pointed out above. I have found, with an antenna constructed in accordance with the arrangement shown in Fig. 2, that signals radiated from Schenectady, New York, have been received in South Africa with considerably greater signal strength than signals received through non-directive radiating systems of other construction, having conslderably greater power input and located at about equal distance from the receiving apparatus. In changing the system to that shown in Fig. 1, however, these signals were considerably increased and this increase appeared to exist in all directions from the antenna.

While I have shown a particular embodiment of my invention it will, of course, be understood that I do not wish to be limited thereto since modifications may be made therein without departing from the spirit and scope of my invention as set forth in the appended claims. Q

What I claim as new and desire to secure by Letters Patent of the United States, is:

1. The combination in a radiating system, of a vertical radiating member having a length substantially equal to one half of a wave length of the waves to be radiated, an oscillatory circuit located at the base of said radiating member, said radiating member and oscillatory circuit being in proximity to but isolated from the'earth whereby oscillations are produced in said radiating member havingavoltage node at the midpoint thereof, and means for supplying high frequency current to said oscillatory circuit.

2. The combination, of a vertical aerial, a horizontal con-ducting member located in proximity to and isolated from the earth, an inductance coil connected to the horizontal conducting member and located at the base of said aerial, said coil being adapted to res onate with the capacity existing between the coil and conducting member and high frequency apparatus connected to points on said coil on opposite sides of a voltage node.

3. The combination in a transmitting system, of a vertical radiating conductor having a length substantially equal to one half ofthe wave length of the wave to be radiated, a horizontal conducting member having a length less than one half of a wave length of the Wave to be radiated, an inductance coil connected to the midpoint of said horizontal member and at the base of said Vertical member and adapted to resonate With the capacity existing between said coil and said horizontal member, a source of high frequency current and connections from said source to points on said coil on opposite sides of a Voltage node. a

In Witness whereof, I have hereunto set my hand this 17th day of August, 1928.

LAURENS A. TAYLOR.

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