US3400402A - Wire antenna extensible along calibrated support means - Google Patents

Description

Sept. 1968 o. c. GALLAGHER ETAL 3,

WIRE ANTENNA EXTENSIBLE ALONG CALIBRATED SUPPORT MEANS Filed March 12, 1965 2 Sheets-Sheet 1 INVENTORS DONALD C. GALLAGHER LESTER W. HAERTHER JOHN A. MIDDLETON EDWARD G. TUTHILL ATTOR EYS Se t. 3, 1968 D. c. GALLAGHER ETAL 3,

WIRE ANTENNA EXTENSIBLE ALONG CALIBRA'I'ED SUPPORT MEANS Filed March 12, 1965 2 Sheets-Sheet 2 INVENTORS QONALD C. GALLAGHER LESTER W HAERTHER JOHN A. MIDDLETON E WARD TUTHILL ATTO E s United States Patent 3,400,402 WIRE ANTENNA EXTENSIBLE ALONG CALIBRATED SUPPORT MEANS Donald C. Gallagher, Marion, Lester W. Haerther, Cedar Rapids, and John A. Middleton and Edward G. Tuthill, Marion, Iowa, assignors to Collins Radio Company, Cedar Rapids, Iowa, a corporation of Iowa Filed Mar. 12, 1965, Ser. No. 439,235 2 Claims. (Cl. 343723) ABSTRACT OF THE DISCLOSURE A wire antenna system dependent in part on terrain features or structures such as existing trees or buildings for antenna support, and utilizing electrically nonconductive glassline cord with spaced frequency markings with relatively light wire as an antenna radiation element strung therealong and supported by the cord. Further, in a short wire version a plurality of counterpoise wires with spaced frequency markings are unreeled to desired frequency tuned lengths in diverse directions along the ground and with the partially unreeled reel ends left laying on the ground in their extended diverse positions.

This invention relates in general to field antenna systems, and in particular, to an antenna system capable of quick, easy erection in the field as a simple, lightweight, and rugged quarter-wave short wire antenna or a halfwave doublet antenna when there is sufficient time and facility therefor.

Prospecting teams, exploration parties, surveying teams, and the military utilize various field antenna systems in meeting various communication operational requirements. Obviously, weight as well as complexity-of various antenna systems can be a problem in field operations. Furthermore, field use requirements impose stringent factors of ruggedness and reliability, in operation for successfully meeting fieldv operational requirements. Cost also becomes a significant factor wheremany antennas are likely to be used in the field and/or where various antennas are likely to be left in place for future use or abandoned in location after use.

. It is, therefore, a principal object of this invention to provide a small and lightweight antenna equipment kit that lends itself to quick and easy erection of a short wire quarter-wave antenna primarily for ground wave propagation and for some long sky-wave propagation, and the erection of a half-wave doublet field antenna using some components common to both antennas when a little more time is available for antenna erection and the primary use is to be for sky-wave propagation over long distances.

Another object is to provide an antenna structure utiliziug glassline antenna supporting cord equipped with A mc. frequency markings starting from the free end of cord reels, and small diameter light antenna wire adjustably unrolled from reels along frequency marked glassline cord for approximate frequency length matched antenna turned settings.

Featuresof this invention useful in accomplishing the above objects include, in a lightweight antenna equipped erection kit for alternate erection of a short wire quarterwave wire antenna and a half-wave'doublet field antenna, reels of electrically nonconductive glassline cord having A mc. frequency markings starting from each reel free end, two of which are utilized in the erection of the halfwave doublet field antenna and one of which is used in erecting the short wire quarter-wave antenna. Two small reels of relatively light lusterless copperweld wire are also included in the kit, two being used as antenna wires with the half-wave doublet field antenna and only one being used with the short wire quarter-wave antenna, and with, in each instance, the antenna wire being unreeled along the frequency marked glassline cord to desired frequency tuned lengths from short high-frequency lengths to longer low-frequency lengths. Three reels of covered and frequency marked copperweld wire are also included for use as counterpoised wires for the short wire quarter-Wave antenna with the frequency markings of the counterpoise wires facilitating unreeling of these wires to approximately the desired frequency tuned lengths of the antenna in divergent directions along the ground. Equipment of the antenna erection kit useful in one and/ or the other of the antennas also includes a weatherproof antenna feed plate, a length of coax conductor, a tie down stake and an additional supply of ground stakes, and casting weights for the throwing of antenna support ing glassline cord over an elevated supporting feature of the environment, for example, the branch of a tree.

Specific embodiments representing what are presently regarded as the best modes of carrying out the invention are illustrated in the accompanying drawings.

In the drawings:

FIGURE 1 represents a side view of a half-wave doublet field antenna installation;

FIGURE 2, a perspective view of a short wire quarterwave antenna installation;

FIGURE 3, a partial view of a glassline reel as fastened down with a ground stake and with glassline cord extended therefrom for use in an antenna installation;

FIGURE 4, a crank face view of the glassline cord reel of FIGURE 3;

FIGURE 5, a view of an antenna reel as mounted in place on a glassline cord;

FIGURE 6, a side view of the antenna reel of FIG- URE 5 with antenna wire and antenna reel positioned at a tuned frequency length on a glassline cord; and,

FIGURE 7, a center interconnection feed plate of the half-wave doublet field antenna.

Referring to the drawings:

The half-wave doublet field antenna 10 of FIGURE 1 is used primarily for skywave radio frequency wave propagation over long distances. Radiation efficiency of this antenna 10 is very good where it can be erected over heights of 30 feet even though radiation from the antenna will be partially vertically polarized since a balun is not used at the antenna feed point in the interest of saving weight, simplicity, and reliability in the field. However, the slight loss in the horizontally polarized radiated signal, as required by a partially vertically polarized emission, does not justify the extra weight and complication incumbent with inclusion of a balun for field use.

With erection of the half-wave doublet antenna 10 to heights of over 30 feet two separate glassline cords 11 unrolled from reels 12 are thrown over relatively high limbs of appropriately spaced trees 13. This is accomplished with casting weights (not shown) fastened to the free ends of glassline cord 11 unraveled from the respective reels 12 for such casting purposes over high tree limbs. The feed ends of the glassline cords 11 are fastened (as shown in FIGURE 7) by clasps 14 to opposite ends of center interconnection feed plate 15. Two antenna reels 16 (refer also to FIGURES 5 and 6) are used with the half-wave doublet field antenna 10 with the free ends of the two antenna wires 17 fastened to center feed terminals 18 of the center feed plate 15. The antenna wires 17 of reels 16 are unrolled along the respective glassline cords 11 to the desired quarter-wave frequency tuned lengths, as gauged by frequency markings 19 in each respective direction along the glassline cords 11 and fastened in place on the cords 11 as by reel clasps 20, and the two quarter-wave lengths of antenna wire 17 together provide the half-wave doublet field antenna 10 lengths.

With increasing antenna lower frequency lengths tape wrappings 21 may be employed at reasonable spacings along the glassline cords 11 to support the relatively fine light antenna wire 17 on the cords 11.

A coaxial conductor feed line 22 may be fastened to the antenna input-output connection of the receivertransmitter unit 23 and the antenna feed plate 15. A strain relief cord 24 is extended from the antenna feed plate to a fastening clamp 25 on the coax feed cable 22, which may be, for example, a 40 foot length of polyfoam filled coaxial conductor line, in order that a free nonweighted coaxial line loop 26 may be provided for nonweighted connections between the coaxial feed line and the antenna feed plate 15.

The glassline reels 12 have, in the interim, been anchored to the ground in appropriate locations by ground stakes 27 driven into the ground through anchor extensions 28 of the respective glassline reels 12. Referring also to FIGURES 3 and 4, slack is removed from the antenna assembly by rewinding glassline cord 11 onto reels 12 by manually rotating the crank arms 29 until the glassline cord is taut to the desired degree, and then locking the reel in position by spring loaded locking clasps 30 which are devised to engage and lock with various grooves 31 around the parameter of flanges of the reels 12.

This provides a half-wave doublet field antenna useful primarily for sky-wave propagation over long distances, the radiation efficiency of which is very good when it is erected to heights over 30 feet. The transmitter 23 output circuits are normally capable of tuning the relatively low VSWR impedance presented by the antenna system. With the transmitter-receiver operating in the receive mode it generally operates at optimum impedances with the halfwave doublet field antenna.

Please refer to the short wire quarter-wave antenna 10' installation of FIGURE 2 for an antenna utilizing many components of an antenna erection kit common to corresponding components used in the erection of the halfwave doublet field antenna 10 of FIGURE 1 with corresponding components numbered the same as a matter of convenience. In this antenna the free end of a glassline cord 11 from a glassline reel 12 is cast over a suitable elevated support, a branch of a tree for example, and the free end is attached to a support stake 32 driven into the ground at an appropriate distance from the suitable elevated support. The free end of an antenna wire 17 from an antenna reel 16 is fastened to the input-output terminal of receiver-transmitter 23 located closely adjacent the ground stake 32. The reel 16 is next unreeled to the desired frequency length as indicated by the frequency markings on the glassline cord 11 and then the antenna reel 16 is clipped to the glassline cord 11, as illustrated in FIGURE 5 and as described hereinbefore with respect to the embodiment of FIGURE 1. The slack from the antenna assembly 10 may then be removed to the desired degree of tautness by rewinding and locking the glassline reel 12 in the rewound position, as has been described with respect to the embodiment of FIGURE 1 and as illustrated in FIGURES 3 and 4. The free ends of, preferably, at least 3 counterpoise wires 33 are connected to the support stake 32 and the wires are unreeled in divergent directions to lengths approximating the selected frequency determined length of antenna wire 17, or more. This is facilitated with the aid of mo. frequency markings 34 on the covering of counterpoise wires 33 of counterpoise wire reels 35, and the wires 33 and the reels 35 are left laying in the divergent extended positions on the ground.

The short wire antenna 10' of FIGURE 2 is used primarily for ground wave RF signal propagation to approximately 25 mile distances and, to some extent, for long sky-wave propagation when there is insufficient time or field facility for erection of a doublet antenna 10 of FIG- URE 1. The short wire antenna with counterpoise, as shown in FIGURE 2, is found to have an RF radiation efficiency of approximately and is quite capable of providing reliable 24 hour communication in a Single Sideband (SSB) mode of operation when the equipment is used over poor ground, in jungle, and in desert terrain. It should be noted that the frequency markings 19 on the glassline antenna support cords 11 are optimized for free space electromagnetic wave signal propagation conditions, and as such, the doublet and the short wire antenna systems will not be perfectly resonant in many situations. However, the tuning range of the transmitter output network of the receiver-transmitter 23 will generally tune and load to the variations in impedances for the typical field variations encountered. Actually, operation of the receiver-transmitter 23 in the receive mode generally pro vides operation under nearly optimum conditions with applicants antennas.

Whereas, this invention is here illustrated and described with respect to specific embodiments thereof, it should be realized that various changes may be made without departing from the essential contribution to the art made by the teachings hereof.

We claim:

1. In a field wire antenna system, an electrically nonconductive antenna supporting cord equipped with frequency markings at predetermined frequency spacings from a first end of the cord the other end of which is an anchor end; radio frequency utilizing means; cord end connective and support means to which said first end of the cord is connected with the cord having been cast over an elevated structural support; means anchoring the anchor end of said nonconductive cord; antenna feed signal connective means connected to said R-F utilizing means; antenna wire means connected to said antenna feed means and extendable along said nonconductive cord from adjacent said first end of the cord to a predetermined desired frequency length as facilitated by the frequency markings on the nonconductive cord; means mounting said antenna wire on said nonconductive cord; wherein the antenna is a short wire antenna, useful for ground wave electromagnetic signal propagation to moderate distances, and to some extent, for long sky-wave electromagnetic signal propagation, with said cord end connective and support means being a ground stake driven into the ground; said antenna wire means being a single antenna wire connected to said antenna feed means and extendable along the nonconductive cord to a predetermined desired frequency length; with the antenna feed means being a feed terminal of said R-F utilizing means with the R-F utilizing means placed in position on the ground adjacent said ground stake; counterpoise wires with predetermined frequency spacing markings from common ends attached to said ground stake with said wires being extendable over and laying along ground surface in diverse directions from said ground stake and with these counterpoise wires being unreeled from counterpoise wire reels that are unreeled and left laying on the ground in their extended diverse positions.

2. The short wire antenna system of claim 1, wherein said short wire antenna system includes at least three counterpoise wires with frequency markings spaced from adjacent ends connected to said ground stake with the counterpoise wires extending in diverse directions over the ground to approximately the frequency selected length of said antenna wire along said nonconductive cord, or to a greater length.

References Cited UNITED STATES PATENTS 1,438,290 12/1922 Beakes 343877 XR 1,895,493 l/l933 Sherman 343-877 2,569,810 10/1951 Hamel et al. 343823 2,778,017 1/1957 Dorcsjak 343823 3,025,524 3/1962 Thies 343823 (Other references on following page) 5 6 UNITED STATES PATENTS Doublet Antenna System Model TD1, Hy-Gain Antenna 3,189,906 6/1965 Kulik et aL 34 710 Products, Lincoln, Nebr., IEEE Convention, Mar. 25, 3,271,774 9/1966 t' 343891XR 1963- 3 The Antenna BOOk, eighth edition (second 3308470 3/1967 Ben 343 886 XR 5 printing), The American Radio Relay League Inc., West Hartford, Conn, copyright 1956, TK6565A6, pp. 190- FOREIGN PATENTS 191 r 525,571 5/1931 Germany. 0 793 5 1951 Germany HERMAN KARL SAALBACH, Primary Examiner.

OTHER REFERENCES 10 M. NUSSBAUM, Assistant Examiner.

Technical Data Report, The Hy-Gain Reel Tape

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