US3068477A

US3068477A - Floating snake antenna

Info

Publication number: US3068477A
Application number: US840980A
Authority: US
Inventors: James J Tennyson
Original assignee: Individual
Current assignee: Individual
Priority date: 1959-09-18
Filing date: 1959-09-18
Publication date: 1962-12-11
Anticipated expiration: 1979-12-11

Description

Dec. 11, 1962 J. J. TENNYSON FLOATING SNAKE ANTENNA 3 Sheets-Sheet 1 Filed Sept. 18, 1959 INVENTOR. Jimi: J 72AM ys /v HTTOPA/tiV- Dec. 11, 1962 J. J. TENNYSON FLOATING SNAKE ANTENNA Filed Sept. 18, 1959 5 Sheets-She 2 INVENTOR. li/n55 J ZEN 7 Decv 11, 1962 J. J. TENNYSON FLOATING SNAKE ANTENNA 3 Sheets-Shet; 3

Filed Sept. 18, 1959 INVENTOR JZ/ma I fi/wvyw/r /77 rae/vsw.

United States Patent 3,068,477 FLOATING SNAKE ANTENNA James J. Tennyson, 32 Brill Ave., Waterford, Conn. l iled Sept. 18, 1959, Ser. No. 840,980 12 Claims. c1. 34s 70e) (Granted under Title 35, US. Code (1952), sec. 266) The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

This invention relates to electrical antennas that are used with receivers or transmitters located aboard small vessels, lifeboat or rafts, and more particularly with 1nflatable and deflatable floating wire antennas.

It is common practice to equip buoys, lifeboats and rafts with radio receiving and transmitting equipment for communication and transmission of position information. The present practice is to employ a vertical wh p antenna in conjunction with the radio system. The whip antenna is either mounted directly to the lifeboator raft or supported by a balloon tied to the raft. Sufficient antenna height in all kinds of weather is not assured where vertical whip antennas are employed due 1n part to sea conditions. Pitching and tossing of the craft changes the impedance of the antenna and consequently the eificiency of transmission is severely reduced and water spray tends to short the antenna and accelerate corrosion. Constant maintenance of the antenna is required when in use in order to insure some transmission of intelligence. The problems outlined above become acute as the frequency of transmission is increased and so the radio system may be limited to relatively low frequencies.

An object of this invention is to provide a floating antenna system which may be collapsed endwise when not in use, but easily and quickly expanded when use is desired, and which will operate satisfactorily over a large frequency spectrum when exposed to changing ocean atmospheric conditions.

Another object of this invention is to provide a floating antenna system for vessels which will have a constant antenna height under all floating conditions and will not be shorted or corroded by sea spray irrespective of the sea state, and may be, when required, readily sunk by its user.

A further object of this invention is to provide a simple, inexpensive, practical, compact, eflicient and inexpensive antenna system for vessels.

Other objects and advantages will be apparent from the following description of an embodiment of the invention, and the novel features thereof will be particularly pointed out hereinafter in connection with the appended claims.

FIG. l is a perspective of a portion of an embodiment made in accordance with this invention, with a portion of the casing removed,

FIG. 2 is a side elevation of the embodiment in a collapsed or deflated condition,

FIG. 3 is a side elevation of the embodiment when emploved in conjunction with a raft,

FIG. 4 is a section of a portion of the embodiment of FIG. 2 taken approximately lengthwise through the center, and

FIG. 5 is similar to FIG. 3 except that the antenna has been inflated.

The same identification numbers are used in the various figures to identify the same or corresponding parts in the various illustrations.

In the embodiment of the invention illustrated in FIG. 1, a hollow, elongated, elastic, closed, watertight casing 6 of electrically insulating flexible sheet material, as for exp nyl or any suitable flexible and water imperice vious plastic sheet material which contains therein electrically insulating disk spacers 7 arranged in seriatim at spaced apart intervals along the length of the casing with their faces transverse to the longitudinal axis 8 of the casing. The casing 6 is preferably cylindrical and the disks of a diameter so as to fit snugly within, and abut the inner wall of the casing. The peripheral edge 9 of each disk is aflixed to the casing abutting that edge by any suitable method as for example by an appropriate waterproof cement or adhesive thereby confining the disk against lengthwise movement relative to the casing. Each disk 7 has a plurality of passage 10 extending therethrough from face to face in order to allow free passage of gas with- -in the casing when the casing is extended and a flexible electrically conducting antenna wire 11 extending in a direction lengthwise of and within the casing is supported centrally of the casing by the disks 7. The wire 11 may be supported by the disks in any suitable manner provided the wire is thusly insulated from the casing 6, as for example, by providing each disk with an aperture 12 at its center through which the wire passes and that portion of the wire within the aperture 12 may be cemented to the inner peripheral edge of the disk aperture 12 to confine the wire against lengthwise movement. The disk spaces the wire from the casing equally on all sides so that the wire will always be the same distance from the water on which the antenna floats and rolls.

In order to permit compact storage and ease of handling, the casing 6 may be provided with an accordian pleat construction and thereby may be readily collapsed or deflated as is illustrated in FIG. 2. The end walls 14 and 15 of the casing are disk-like rigid plastic members hermetically sealed to the casing so as to form a water and air tight joint. A short conduit 13 extends through an opening and beyond in one end wall 14 of the casing and in so doing is provided with a tight seal at its periphery so as to prevent the passage of water into casing 6 or the escape of gas from within the casing. A check valve (not shown) is disposed within the conduit 13 whereby the casing may be inflated or distended by the admission of gas under pressure through the check valve from a suitable source of compressed gas, as for example, container 18 and deflated by means of the check valve. The gas so introduced, fills the entire casing passing through openings 10 in the disk spacers 7. The antenna wire 11 which is centrally disposed within the casing extends from one end wall 15 of the casing where it may be attached, along the longitudinal axis of the casing through an aperture 16 in the opposite end wall 14 and beyond. A tight seal is provided between the antenna wire 11 and the inner peripheral wall of aperture 16 so as to prevent the escape of gas from and the admission of water into the casing. That portion of the wire 11 exterior to the casing has an insulated coating 17 and may be also used as a tow line between the raft or lifeboat 20 and the floating antenna 21 as illustrated in FIG. 3. A separate tow line may be aflixed to the casing walls 14 or 15 where additional strength is required or where sea conditions will so warrant and another electrical connection provided for the antenna wire 11 to the raft 20.

A sectional portion of one form of the floating antenna is illustrated in FIG. 4 wherein the casing construction allows the antenna casing 6 to fold as shown so that the disks 7 are closely spaced in a face to face relationship, and the portion of the flexible antenna wire 11 which is disposed between the individual disks 7 is bent into a U shape when the floating antenna is collapsed. It is evident from the showing of FIGURE 4 that the antenna wire itself when bent into a U shape upon collapse of the antenna can extend out to the peripheral edge of the disk 7. Since the wire is so shaped, its maximum length between disks would be approximately equal to the diameter of the disk provided there existed only one U bend of the antenna wire between adjacent disks. In other words, the wire first extends out from the center to the edge of the disk and then back thereby being equal to two radii, or the diameter of the casing. The disk thickness is very small as compared to its diameter and therefore the approximate length of the antenna when fully inflated (extended) is equal to the number of disks multiplied by their diameter. Of course, where multiple U bends of the wire between disks are desired the inflated length of the antenna can be many times that specified above. Fine stranded wire may be employed for the antenna wire so that it will not break or rupture after the antenna has been inflated and collapsed several times. A sectional portion of the floating antenna with the casing inflated is illustrated in FIG. 5 and it should be noted that the antenna wire 11 is adequately supported throughout its entire length by the disks 7 thereby maintaining a fixed, constant physical relationship with respect to the casing 6 and with respect to the surface of the fluid on which the antenna floats.

The overall length of the inflated antenna is predetermined by the frequency band of the communication equipment with which it is employed. A cylindrical shape for the casing is preferred for the inflated antenna since the antenna wire is thereby positioned centrally therein and any roll or turning of the floating antenna on the water on which it floats will not alter the spacing of the wire from the water surface and a constant antenna height is thereby maintained. The casing 6 protects the antenna wire from atmospheric variations and water spray while the disks 7 position and support the Wire and minimize longitudinal twisting of the antenna.

When not in use or while being stored, the antenna is collapsed in length. The compact size of the collapsed antenna facilitates its use where space is critical as for example, on lifeboats, rafts and aboard airplanes for transportation. The total number of disks may be predetermined so as to result in a non-buoyant or sinkable antenna due to the total weight of the disks as compared to the total antenna volume when the gas enclosed within the casing is released. This sinkable feature is of prime importance under certain circumstances where detection is to be avoided, for instance, a floating antenna for a submarine which suddenly submerges in order to avoid detection and can not leave a buoy marking its prior location. It should be noted that the casing 6 is free to flex since the space between the disks 7 is free of any internal structure which would resist the outward or inward move; ment of the casing between the disks and so resist endwise collapse of the antenna.

It will be understood that various changes in the details, materials and arrangement of parts, which have been herein described and illustrated in order to explain the nature of this invention, may be made by those skilled in the art within the principle and scope of the invention as expressed in the appended claims.

I claim:

1. A floating antenna for use with transmitting and receiving equipment aboard a vessel to which the antenna may be connected, which comprises a hollow, closed, elongated, and lengthwise collapsible, watertight casing of electrically insulating material, a flexible metal antenna wire extending in a direction lengthwise of and within said casing, insulated thereby from the exterior of the casing but having a circuit connection on the exterior of one end wall of the casing, rigid spacer means whose dimension lengthwise of said casing is small as compared with the transverse dimension of said casings, said spacer means disposed within said casing at intervals along its length supporting said wire in spaced relation to the peripheral wall of said casing when said casing is extended and each having a passage from face to face through which a gas may pass, a towing connection to one end wall of said casing, the interior of said casing between substantially all of said spacer means being free of any structure which would prevent endwise collapse of said casing, and means adjacent and connected to the interior of the towed end of the casing for admitting thereto a gas under pressure and thereby causing extension of said casing to its full length from a collapsed condition said full length being at least the product of the number of spacer means and the transverse dimension of said casing.

2. The antenna according to claim 1, wherein each of said spacer means is a member disposed tranversely across the interior of said casing, through which said antenna wire extends and having a passage open from face to face for the passage of said gas.

3. The antenna according to claim 1, wherein said casing when extended is cylindrical in shape, and each said wire supporting means is a disk of electrically insulating material through the interior face area of which said antenna wire extends and having a passage from face to face through which said gas may pass in causing said extension of said casing.

4. The antenna according to claim 3, wherein said antenna wire is disposed approximately centrally of the casing when said casing is extended.

5. The antenna according to claim 4, wherein said casing has an accordian pleat construction and is formed of water impervious flexible, elastic sheet material enabling its collapse and extension endwise.

6. The antenna according to claim 5, wherein said gas admitting means includes a check valve in a conduit connected and opening into the interior of said casing and a source of compressed gas connected to said conduit for inflating endwise said casing.

7. The antenna according to claim 1, wherein said casing has an accordian pleat construction enabling its collapse and extension endwise and formed of water impervious, flexible sheet material.

8. The antenna according to claim 1, wherein said gas admitting means includes a check valve ina conduit connected to and opening into the interior of one end wall of said casing.

'9. The antenna according to claim 8, and a source of compressed gas connected to said conduit and through the valve to the interior of said casing.

10. The antenna according to claim 1, wherein said casing has its peripheral wall formed of flexible, elastic sheet material.

11. The antenna according to claim 1, wherein said antenna wire is disposed approximately centrally of the casing when the casing is extended whereby if the casing rolls about its longitudinal axis the height of the antenna wire above the water in which the antenna may be floating remains fairly constant.

12. The antenna according to claim 1, wherein said towing connection is an insulated wire connected at its end, which is attached to one end wall of the casing, to said circuit connection of said antenna wire.

References Cited in the file of this patent UNITED STATES PATENTS 1,116,835 Neumann Nov. 10, 1914 1,285,940 Chodakowski Nov. 26, 1918 1,557,049 Hammond Oct. 13, 1925 2,067,337 Polatzek Jan. 12, 1937 2,888,675 Pratt et a1 May 26, 1959 2,936,453 Coleman May 10, 1960