JP5696847B2 - Antenna top for radio buoy and method for manufacturing the same - Google Patents

Description

  The present invention relates to an antenna arm for a radio buoy used at sea, and more particularly to an antenna arm using a coaxial cable as a conductor and a manufacturing method thereof.

Conventionally, so-called buoys are used as navigational signs at sea and as installation signs for fishing nets. Among these buoys, there are radio buoys that transmit radio waves to clarify their positions and help the signs. Radio buoy antennas generally consist of an upper arm incorporating an antenna conductor, a loading coil (if necessary), and a lower arm that secures the antenna to the buoy. Conventionally, braided wires have been widely used as antenna conductors. (For example, refer to Patent Document 1).

  Such an antenna conductor is manufactured by, for example, covering a core rod with a braided wire, solidifying the state with an epoxy resin, and then pulling out the core rod. Further, in Patent Document 1, a braided wire is developed so as to be in close contact with the inner wall of the tubular member, and thereafter, a urethane foam is filled in the hollow portion of the tubular member, and the braided wire is bonded and fixed to the inner wall of the tubular member. A manufacturing method is disclosed.

Japanese Examined Patent Publication No. 4-61521

  However, since the braided wire formed by braiding the conductor wire easily expands and contracts, the manufacturing process as described above (for example, the step of covering the antenna core rod with the braided wire or the inner wall of the tubular member) Thus, in the step of developing the braided wire), it is difficult to keep the density of the conductors constituting the braided wire uniform, and as a result, there is a problem in that the quality of the antenna upper collar varies.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a radio buoy antenna upper arm that can be easily manufactured without causing variations in quality, and a method for manufacturing the same.

(Aspect of the Invention)
The following aspects of the present invention exemplify the configuration of the present invention, and will be described separately for easy understanding of various configurations of the present invention. Each section does not limit the technical scope of the present invention, and some of the components of each section are replaced, deleted, or further while referring to the best mode for carrying out the invention. Those to which the above components are added can also be included in the technical scope of the present invention.

(1) a coaxial cable having a predetermined length, seen including a reinforcing member for reinforcing the strength of the coaxial cable, said with coaxial cable constituting a radiating element of the antenna, the outer conductor and the inner conductor of the coaxial cable The antenna for the radio buoy is characterized by being short-circuited with the terminal on the power feeding side of the above (claim 1).

( 2 ) A step of preparing a coaxial cable having a predetermined length, a step of reinforcing the strength of the coaxial cable, a step of configuring the coaxial cable as a radiating element, an outer conductor and an inner conductor of the coaxial cable And a step of short-circuiting the terminal on the power feeding side . (Claim 2 ).

According to the upper antenna for a radio buoy according to the present invention, an outer conductor (braided wire) incorporated in a coaxial cable in a uniformly developed state is used as an antenna conductor, and has excellent high frequency characteristics and quality. It is possible to realize an antenna top without variation.
In addition, according to the method for manufacturing a radio buoyant antenna arm according to the present invention, it is possible to easily manufacture an antenna arm with excellent high frequency characteristics and no variation in quality without requiring a process of deploying or arranging a braided wire. It becomes possible to do.

(A) is a side view of an upper arm of the antenna for a radio buoy according to an embodiment of the present invention, (b) is an enlarged view showing an internal configuration of part A, and (c) is an enlarged view showing an internal configuration of part B. It is.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. As shown in FIG. 1A, a radio buoy antenna upper collar (hereinafter also referred to as an antenna upper collar) 10 in the present embodiment has a tubular member 12, and its upper end (right end in the figure). Is attached with an upper mounting bracket 14 and a lower mounting bracket 16 is mounted at the lower end (left end in the figure). As shown in FIGS. 1B and 1C, a coaxial cable 20 that functions as a radiating element in the antenna upper collar 10 is accommodated inside the tubular member 12. The tubular member 12 is formed of, for example, FRP (Fiber Reinforced Plastics), and functions as a reinforcing member that reinforces the strength of the coaxial cable 20.

  The antenna upper rod 10 normally constitutes an antenna for a radio buoy together with the antenna lower rod and a loading coil (if necessary), and is erected on the float portion of the radio buoy. However, as these members and configurations, conventionally known ones can be applied, and therefore illustration and description thereof are omitted.

Here, the coaxial cable 20 includes an inner conductor 26 made of copper wire, an insulator 22 that covers the periphery of the inner conductor 26, an outer conductor 24 that includes a braided wire that covers the periphery of the insulator 22, and an outer conductor 24. It is composed of a protective coating 28 that covers the periphery, and has a predetermined length according to the frequency used in the antenna including the antenna upper collar 10.
Such a coaxial cable 20 may be, for example, a 5C-2V cable conforming to JISC3501. In this case, the insulator 22 is made of polyethylene, the outer conductor 24 is made of a single braid of annealed copper wire, and the protective coating 28 is made of PVC.

Here, referring to FIG. 1B, which is an enlarged view of part A of FIG. 1A, and FIG. 1C, which is an enlarged view of part B of FIG. A detailed configuration thereof will be described.
First, the coaxial cable 20 is prepared by cutting a long unprocessed coaxial cable into a predetermined length. Then, the protective coating 28 at both ends of the coaxial cable 20 and the insulator 22 at one end are peeled off by a required length. Next, as shown in FIG. 1B, the exposed inner conductor 26 and outer conductor 24 are inserted into the upper mounting bracket 14 at one end on the side where the insulator 22 is peeled, and the outer conductor 24 is connected to the upper mounting bracket 14. 14 is soldered (C (shaded part)). Next, the coaxial cable 20 is inserted into the tubular member 12. Before inserting the coaxial cable 20 into the tubular member 12, a waterproof coating material (for example, a silicone potting material) may be applied to the exposed outer conductor 24.

Then, after fitting the O-ring 31 to the upper mounting bracket 14 and mounting the tip cap 18 on the upper mounting bracket 14, the upper mounting bracket 14 is inserted into the tubular member 12 so that the tubular member 12 is inserted therein. Install on one end. At this time, an adhesive may be applied to the surface corresponding to the upper mounting member 14 of the tubular member 12.

  Next, the insulator 22 at the other end of the coaxial cable 20 is peeled off by a necessary length. Next, as shown in FIG.1 (c), the lower attachment metal fitting 16 is attached to the other end side of the tubular member 12 so that the tubular member 12 may be inserted in the inside. At this time, an adhesive may be applied to the surface of the tubular member 12 corresponding to the lower mounting bracket 16. Then, the outer conductor 24 and the inner conductor 16 inserted into the lower mounting bracket 16 by mounting the lower mounting bracket 16 to the tubular member 12 (after removing an excess portion of the outer conductor 24 if necessary) Soldering is performed inside the mounting bracket 16 (D (hatching) portion). As a result, the outer conductor 24 of the coaxial cable 20 and the terminal of the inner conductor 22 on the lower end side of the upper antenna 10 are short-circuited.

  Although not shown, after attaching necessary members such as a washer and an O-ring to the lower mounting bracket 16, the lower mounting bracket 16 is mounted on the antenna lower arm (or loading coil), and the lower mounting bracket is mounted. By connecting an antenna wire drawn from a communication device such as a transmission device and / or a reception device included in the radio buoy to the lower mounting bracket 16 (when present, via a loading coil) with 16 as a connection conductor on the power feeding side The antenna for the radio buoy including the antenna top 10 is configured.

  Further, for structural reinforcement and waterproofing, a resin material is adhered and solidified by, for example, winding an epoxy FRP-impregnated cloth 19 around a boundary portion between the lower mounting bracket 16 and the tubular member 12 (FIG. 1A). Further, an adhesive tape 33 having a resin (for example, fluorine resin) as a base material may be wound and attached to a boundary portion between the tip cap 18 and the upper mounting bracket 14 (FIG. 1B). .

  Thus, since the coaxial cable 20 is used as a radiating element in the antenna upper collar 10, the process of deploying and arranging the braided wire as in the conventional antenna upper collar is not necessary in the manufacturing process. The uniformly braided wire (external conductor) 22 provided is utilized as an antenna conductor, and it is possible to configure the antenna upper collar 10 having no variation in quality. Further, the coaxial cable 20 is provided with a material and a structure having excellent high frequency characteristics necessary for a high frequency transmission path, and is advantageous as a radiating element of an antenna for high frequency transmission / reception.

  It should be noted that in the antenna upper collar 10, the outer conductor 24 of the coaxial cable 20 and the terminal on the lower end side (that is, the feeding side) of the inner conductor 26 are short-circuited. This configuration is advantageous in that the reception sensitivity at a long distance is improved. According to the investigation by the present inventors, the antenna including the antenna upper rail 10 is the same as that of the antenna cable except that the outer conductor 24 of the coaxial cable 20 and the lower end of the inner conductor 26 are not short-circuited. It was revealed that the reception sensitivity was improved by about 0.6 dB to 1.0 dB in the long-distance measurement of 70 km and about 1.0 dB in the long-distance measurement of 290 km as compared with the antenna including the antenna.

  In the same investigation, it has also been found that whether or not the terminals on the upper end side of the outer conductor 24 and the inner conductor 26 of the coaxial cable 20 are short-circuited has a small influence on the sensitivity of the antenna. In addition, whether or not the outer conductor 24 of the coaxial cable 20 and the terminal on the upper end side of the inner conductor 26 are short-circuited can be appropriately determined in consideration of workability of soldering work and the like.

  As mentioned above, although this invention was demonstrated according to preferable embodiment, this invention is not limited by embodiment mentioned above. For example, in the antenna upper collar 10, the reinforcing member that reinforces the strength of the coaxial cable 20 is the tubular member 12, and the coaxial cable 20 is inserted into the tubular member 12 to reinforce the strength of the coaxial cable 20. The reinforcement of the coaxial cable 20 may be performed by using a resin material such as epoxy FRP as a reinforcing member and attaching and solidifying the resin material on the coaxial cable 20.

  10: antenna upper collar, 12: tubular member (reinforcing member), 14: upper mounting bracket, 16: lower mounting bracket, 18: tip cap, 20: coaxial cable, 22: insulator, 24: outer conductor, 26: inner Conductor, 28: Protective coating

Claims (2)

A coaxial cable having a predetermined length, said saw including a reinforcing member for reinforcing the strength of the coaxial cable, said with coaxial cable constituting the radiating element, an outer conductor and an inner conductor power supply side terminal of the coaxial cable And an antenna for a radio buoy characterized by being short-circuited . A step of preparing a coaxial cable having a predetermined length, a step of reinforcing the strength of the coaxial cable, a step of configuring the coaxial cable as a radiating element, a feeding side of the outer conductor and the inner conductor of the coaxial cable, And a step of short-circuiting the terminal .

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