Antenna replacement method and temporary facility

Abstract

To provide an antenna replacement method and a temporary facility with which it is possible to shorten the work time of antenna replacement.SOLUTION: The antenna replacement method is a method for replacing an existing antenna unit 2 which is installed to an antenna installation section 12 located at the top of a steel tower 1, and in which an existing antenna 22 is attached to an existing antenna pole 21, with a new antenna unit 6 in which a new antenna 62 is attached to a new antenna pole 61. The antenna replacement method includes: a temporary installation step for forming a temporary facility 4 having a temporary pole 41; and a rotationally interchange step for holding the existing antenna unit 2 removed from the antenna installation section 12 and the new antenna unit 6 by using the temporary facility 4, and causing the existing antenna unit 2 and the new antenna unit 6 to turn around the temporary pole 41.SELECTED DRAWING: Figure 8

Description

[Technical field]

[0001] The present invention relates to an antenna replacement method and a temporary installation. [Background technology]

[0002] Some steel towers have an antenna unit attached to the top for transmitting radio waves for, for example, terrestrial digital television broadcasting. The antenna unit includes an antenna pole attached to the top of the steel tower and an antenna attached to the antenna pole.

[0003] Patent Document 1 discloses a method for replacing an existing antenna unit attached to the top of a steel tower with a new antenna unit. In the method described in Patent Document 1, a facility (hereinafter also referred to as a lifting facility) is constructed on the top of the steel tower, the facility having a gin pole, a support member, an arm, a base end pulley, a tip end pulley, an antenna wire, and a movable pulley for lifting and moving the antenna unit. The gin pole is fixed to the top of the steel tower and is long in the vertical direction. The support member protrudes upward from the gin pole and is attached rotatably relative to the gin pole. The arm is fixed to the support member and extends to the gin pole and a position on the outer periphery of the gin pole. The pulley is attached to the arm. The antenna wire is hung on the pulley and suspended from the arm. The movable pulley is hung from the antenna wire and has a hook for lifting the antenna unit.

[0004] Furthermore, in the method described in Patent Document 1, a relocation pole is also constructed for temporarily locating the existing antenna unit.

[0005] In the method described in Patent Document 1, the existing antenna unit is removed from the tower, and the removed existing antenna unit is relocated onto a relocation pole using a lifting facility.

[0006] After that, the movable pulley of the lifting equipment is removed from the existing antenna unit and lowered to the ground. The new antenna unit prepared on the ground is then hung from the movable pulley, and the new antenna unit is lifted from the ground to the top of the tower and attached to the tower. In this manner, the antenna replacement is carried out. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Patent No. 4920517 Summary of the Invention [Problem to be solved by the invention]

[0008] In the method described in Patent Document 1, during the antenna replacement work, it is necessary to detach the movable pulley of the hoisting equipment from the existing antenna unit and lower it to the ground, and then hoist the newly installed antenna unit up to the top of the tower and replace it, making it difficult to shorten the work time for antenna replacement.

[0009] The present invention has been made in consideration of the above-mentioned circumstances, and has an object to provide an antenna replacement method and temporary equipment that can shorten the work time required for antenna replacement. [Means for solving the problem]

[0010] In order to achieve the above-mentioned object, the present invention provides an antenna replacement method for replacing an existing antenna unit, which is installed on an antenna installation section located at the top of a steel tower and has an existing antenna attached to an existing antenna pole, with a new antenna unit, which has a new antenna attached to a new antenna pole, the antenna replacement method comprising: a temporary installation process for forming a temporary facility having a temporary pole that is attached to the steel tower and extends in the vertical direction; a rotational replacement process for holding the existing antenna unit removed from the antenna installation section and the new antenna unit using the temporary facility and revolving the existing antenna unit and the new antenna unit around the temporary pole; and an installation process for installing the new antenna unit disposed above the antenna installation section by the rotational replacement process to the antenna installation section.

[0011] Furthermore, in order to achieve the above-mentioned object, the present invention provides a temporary facility used when replacing an existing antenna unit, which is installed at an antenna installation section located at the top of a steel tower and has an existing antenna attached to an existing antenna pole, with a new antenna unit, which has a new antenna attached to a new antenna pole, the temporary facility comprising a temporary pole that can be attached to the steel tower and extends in the vertical direction, the temporary facility being configured to be able to hold both the existing antenna unit removed from the antenna installation section and the new antenna unit, and the temporary pole being attached to the steel tower so as to be rotatable on its own axis. Effect of the Invention

[0012] According to the present invention, it is possible to provide an antenna replacement method and temporary equipment that can shorten the work time required for antenna replacement. [Brief description of the drawings]

[0013] [Figure 1] FIG. 2 is a front view of the upper part of a tower to which an existing antenna unit is attached in the first embodiment. [Diagram 2] 4 is a flowchart of an antenna replacement method according to the first embodiment. [Diagram 3] FIG. 11 is a front view of the upper part of the tower showing the state after the temporary installation process in the first embodiment. [Figure 4] FIG. 11 is a front view of the upper part of the tower showing the state after the first lifting step in the first embodiment. [Diagram 5] 5 is a cross-sectional view taken along line AA in FIG. 4 according to the first embodiment. [Figure 6] 5 is a cross-sectional view taken along line AA in FIG. 4 after a posture adjusting step in the first embodiment. [Figure 7] FIG. 11 is a front view of the upper part of the tower showing the state after the attitude adjustment process in the first embodiment. [Figure 8] FIG. 11 is a front view of the upper part of the tower showing the state after the second lifting step in the first embodiment. [Figure 9] FIG. 11 is a front view of the upper part of the tower, showing the state after the rotation and replacement process in the first embodiment. [Figure 10] FIG. 1 is a front view of the upper part of the tower showing the state after the installation process in the first embodiment. [Figure 11] FIG. 2 is a front view of the upper part of the tower showing a state during an inspection process in the first embodiment. [Figure 12] FIG. 2 is a front view of the upper part of the tower during the lowering process in the first embodiment. [Figure 13] FIG. 11 is a front view of the upper part of a tower to which an existing antenna unit is attached in the second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] [First embodiment] A first embodiment of the present invention will be described with reference to Figures 1 to 12. Note that the embodiment described below is shown as a preferred specific example for carrying out the present invention, and while there are some parts that specifically exemplify various technical matters that are technically preferable, the technical scope of the present invention is not limited to this specific embodiment.

[0015] 1 is a front view of the upper part of a steel tower 1 to which an existing antenna unit 2 is attached in this embodiment. In this embodiment, the steel tower 1 is a long structure in the up-down direction (i.e., vertical direction) having a steel framework structure 11. The steel tower 1 has, at its top, a columnar antenna installation section 12 extending in the up-down direction. A flange 121 protruding outward from the upper end of the antenna installation section 12 is formed, and the existing antenna unit 2 is fixed onto the flange 121.

[0016] The existing antenna unit 2 is used to transmit radio waves in the UHF (Ultra High Frequency) band for terrestrial digital television broadcasting, for example. The existing antenna unit 2 includes an existing antenna pole 21 and an existing antenna 22.

[0017] The existing antenna pole 21 is attached to the top of the steel tower 1, specifically to the flange 121 of the columnar antenna installation part 12 provided on the steel tower 1. The existing antenna pole 21 has annular flanges 211 protruding outward from the lower and upper ends. The lower flange 211 of the existing antenna pole 21 is overlapped with the flange 121 of the antenna installation part 12 and fastened with bolts. A flange 31 formed at the lower end of the lightning rod 3 so as to protrude outward from the outer periphery is overlapped with the upper flange 211 of the existing antenna pole 21 and fastened with bolts.

[0018] The existing antenna 22 is a panel-type antenna in which an antenna element (not shown) is covered by a panel 221. The antenna element can be, for example, a twin loop antenna, a dipole antenna, etc. The panel 221 has, for example, a metallic reflector 221a arranged to face the existing antenna pole 21 and capable of reflecting radio waves emitted by the antenna element, and a cover 221b that covers the reflector 221a from the side opposite the existing antenna pole 21 to protect the antenna element.

[0019] In this embodiment, the existing antennas 22 are provided on three surfaces at different positions in the circumferential direction of the existing antenna pole 21. Furthermore, the existing antennas 22 are provided in two rows in the vertical direction. Each of the existing antennas 22 has a predetermined directivity in the horizontal direction. The existing antennas 22 are designed to be oriented so that they can transmit radio waves in a desired direction.

[0020] The configuration of the existing antenna unit 2 is not limited to the above-mentioned one, so long as it is attached to the top of the steel tower 1. For example, the existing antenna unit 2 may have a different number of faces of the existing antenna 22 at each position in the vertical direction, a different number of rows in the vertical direction, and the like, from those described above.

[0021] The existing antenna unit 2 may need to be replaced, for example, after a long period of use (several decades or more). The antenna replacement work may be carried out using a crane truck, but there may be cases where the tower 1 is located in a place where a crane truck cannot be parked next to it, such as in a mountain, or where the tower 1 is too high to use a crane truck.

[0022] In addition, antenna replacement work that affects terrestrial digital television broadcasting cannot be carried out during terrestrial digital television broadcasting hours, and must be completed within a short period of time during which broadcasting is suspended. It is difficult to secure a long period of time during which broadcasting is suspended for multiple broadcasting stations, so it is desirable to complete antenna replacement work within a short period of time, such as within a few hours at night (e.g., 2 or 3 hours).

[0023] Therefore, the antenna replacement method of this embodiment is devised so that the antenna replacement work can be performed without using a crane truck and can be completed in a short time.

[0024] FIG. 2 is a flowchart of the antenna replacement method according to this embodiment. The antenna replacement method of this embodiment includes a preparation step S1, an interruption work S2 carried out during an interruption of terrestrial television broadcasting (e.g., at night), and a post-interruption work S3 carried out after the interruption work S2. Hereinafter, each step of the antenna replacement method of this embodiment will be described in detail.

[0025] (Preparation work S1) In the preparation work S1, first, the temporary installation step S11 is carried out. Fig. 3 is a front view of the upper part of the tower 1 showing the state after the temporary installation step S11. The temporary installation step S11 is a step of constructing a temporary facility 4 on the upper part of the tower 1. In the temporary installation step S11, first, mounting parts 51, 52 for mounting the temporary facility 4 on the tower 1 are fixed. In this embodiment, the mounting parts 51, 52 are attached to the framework structure 11 of the tower 1. In this embodiment, the two mounting parts 51, 52 are fixed to two positions in the vertical direction on the top of the tower 1.

[0026] The lower mounting part 51 has a bottomed cylindrical shape that is open on the upper side, and the lower end of the temporary pole 41 (described later) that constitutes the temporary facility 4 is inserted into the lower mounting part 51. The mounting part 51 has a lubricant such as grease arranged therein, for example, so that the temporary pole 41 can rotate inside. The upper mounting part 52 is formed directly above the lower mounting part 51, and has, for example, a band that can fasten the temporary pole 41. For example, the inner diameter of the band of the mounting part 52 is larger than the outer diameter of the temporary pole 41 (excluding the flange 411a) before being attached to the temporary pole 41, and the band is fastened to fix the temporary pole 41, and the band is loosened to enable the temporary pole 41 to rotate inside the mounting part 52.

[0027] The temporary facility 4 is attached to the attachment portions 51, 52. The temporary facility 4 includes a temporary pole 41, an existing side extension portion 42, a new side extension portion 43, an existing side wire 44, a new side wire 45, a winch wire 40, and a connecting member 46.

[0028] The temporary pole 41 is formed by stacking a plurality of cylindrical split poles 411 one on top of the other in the vertical direction. The lowest split pole 411 is inserted into and supported by the two mounting parts 51, 52. The upper end of the lowest split pole 411 and the upper and lower ends of the other split poles 411 are each formed with a flange 411a protruding outward. The flanges 411a of the split poles 411 adjacent in the vertical direction are stacked and bolted together. The flange 411a located at the upper end of the uppermost split pole 411 constitutes a lightning rod mounting part to which the lightning rod 3 attached to the existing antenna unit 2 can be attached. During the antenna replacement work, the lightning rod 3 is moved from the existing antenna unit 2 to the uppermost split pole 411. The lightning rod 3 removed from the existing antenna unit 2 is moved onto the flange 411a of the uppermost split pole 411 by being stacked on the flange 411a of the uppermost split pole 411 and bolted together. The lightning rod 3 is electrically connected to the tower 1 via a temporary pole 41.

[0029] An existing-side overhang 42 and a new-side overhang 43, which protrude in opposite directions, are attached to the uppermost divided column 411. The existing-side overhang 42 and the new-side overhang 43 are attached so as to protrude in opposite directions at 180° from each other when viewed from the top-bottom direction from the temporary column 41. The existing-side overhang 42 and the new-side overhang 43 can be formed from angle material, flat plate, or the like.

[0030] Two pulleys 47 are attached to the existing side overhang 42. In this embodiment, each pulley 47 is a two-wheel pulley equipped with two sheaves. The existing side wire 44 is hung on one sheave of the pulley 47, and nothing is hung on the other sheave, but a winch wire 40 (described later) is hung on it later. One end of the existing side wire 44 is attached to the existing antenna unit 2, and the other end is passed through a small winding device 49a attached to the temporary pole 41. The small winding device 49a can manually wind or unwind the existing side wire 44, and can be, for example, a Chillhole (registered trademark).

[0031] Two pulleys 48 are attached to the new installation side overhang 43. In this embodiment, each pulley 48 is a two-wheel pulley equipped with two sheaves. A winch wire 40 is hung on one sheave of the pulley 48, and nothing is hung on the other sheave, but a new installation side wire 45 described later is hung on it later. One end of the winch wire 40 extends to the ground 100, and a new antenna unit (see reference number 6 in FIG. 4 described later) that is to replace the existing antenna unit 2 is attached to it, and the other end extends to the ground 100 and can be wound up or rewound by a winch 10 installed on the ground 100.

[0032] The small winding device 49a and a small winding device 49b described below are used by workers at the top of the steel tower 1, for example, when changing the position of the existing antenna unit 2 or the new antenna unit 6. On the other hand, when moving the existing antenna unit 2 or the new antenna unit 6 over a long distance between the ground 100 and the top of the steel tower 1, the winch 10 is used.

[0033] The temporary pole 41 and the existing antenna pole 21 are connected by a connecting member 46. The connecting member 46 is a member for connecting the temporary pole 41 to at least one of the existing antenna unit 2 and the new antenna unit 6.

[0034] First, the two existing side fixing parts 461 constituting the connecting member 46 are attached to the existing antenna pole 21. The two existing side fixing parts 461 are fixed to the existing antenna pole 21 at a portion above the existing antenna 22 and a portion below the existing antenna 22. FIG. 5 is a diagram showing the connecting member 46 as seen from above, the details of which will be described later. The existing side fixing part 461 has a band 461a capable of fastening the existing antenna pole 21, and a mounting plate 461b protruding from the band 461a to one side in the horizontal direction. The existing side fixing part 461 is attached to the existing antenna pole 21 so that the mounting plate 461b is in a position protruding toward the temporary pole 41.

[0035] 3, two temporary pole fixing parts 462 constituting the connecting member 46 are attached to the temporary pole 41. The vertical positions of the two temporary pole fixing parts 462 are aligned with the vertical positions of the two existing side fixing parts 461. As shown in FIG. 5, the temporary pole fixing part 462 has a band 462a capable of fastening the temporary pole 41, and a pair of mounting plates 462b, 462c protruding from the band 462a to opposite sides in the horizontal direction. The temporary pole fixing part 462 is attached to the temporary pole 41 such that one mounting plate 462b protrudes from the band 462a toward the existing antenna pole 21 side.

[0036] 3, the temporary-pole fixing part 462 and the existing-side fixing part 461, which are at the same position in the up-down direction, are connected by two existing-side connecting parts 463 constituting the connecting member 46. The existing-side connecting parts 463 are made of a long angle material, a flat plate, or the like. As shown in FIG. 5, one end of the existing-side connecting part 463 is fastened to the mounting plate 461b with a bolt, and the other end is fastened to the mounting plate 462b of the temporary-pole fixing part 462 with a bolt.

[0037] 3, a third temporary pole fixing part 462 is fixed to the temporary pole 41 further below the two temporary pole fixing parts 462. This temporary pole fixing part 462 has the same configuration as the other temporary pole fixing parts 462 except that it does not have a mounting plate 462b. The temporary pole fixing part 462 at the lowest position is provided at a position where the vertical distance L1 from the temporary pole fixing part 462 at the central position to the temporary pole fixing part 462 at the highest position is equal to the vertical distance L2 from the temporary pole fixing part 462 at the central position to the temporary pole fixing part 462 at the lowest position.

[0038] As shown in Fig. 2, after the temporary installation step S11, a first pulling-up step S12 is carried out. Fig. 4 is a front view of the upper part of the tower 1 showing the state after the first pulling-up step S12. Fig. 5 is a cross-sectional view taken along line AA in Fig. 4. The first pulling-up step S12 is a step in which the newly installed antenna unit 6 is pulled up from the ground 100 to the upper part of the tower 1 using the temporary equipment 4.

[0039] The new antenna unit 6 includes a new antenna pole 61 and a new antenna 62. The configuration of the new antenna unit 6 can be the same as that of the existing antenna unit 2. Note that, in FIG. 4 and FIGS. 7 to 11 described later, an example is shown in which the vertical length of the new antenna unit 6 is shorter than the vertical length of the existing antenna unit 2, but this is not limited to this. The new antenna unit 6 may have a different configuration from the existing antenna unit 2, or may have the same configuration. For example, the new antenna unit 6 and the existing antenna unit 2 may have different directivities in the horizontal direction. The configuration of the new antenna unit 6 can be appropriately determined depending on the situation of the radio wave transmission target area at the antenna replacement location, the antenna replacement time, etc.

[0040] In the first pulling-up process S12, as shown in FIG. 3, the winch wire 40 extended to the ground 100 is attached to the new antenna unit 6 (see FIG. 4), and the winch 10 winds up the winch wire 40, thereby pulling up the new antenna unit 6 (see FIG. 4) to the top of the tower 1. As shown in FIG. 4, the new antenna unit 6 is stopped at a position lower than the position of the existing antenna unit 2 so as not to interfere with the radio waves emitted from the existing antenna unit 2. Then, the new side wire 45 passed through the small winding device 49b attached to the temporary pole 41 is hung on the pulley 48 and attached to the top of the new antenna unit 6. The small winding device 49b has a configuration similar to that of the small winding device 49a. After the new side wire 45 is wound and fixed by the small winding device 49b, the winch 10 is rewound and the winch wire 40 is removed from the new antenna unit 6. The removed winch wire 40 is hung on the sheave of the pulley 47 on the side to which the existing wire 44 is not hung, and is attached to the top of the existing antenna unit 2. That is, the existing wire 44 and the winch wire 40 are hung on the top of the existing antenna unit 2.

[0041] The new antenna unit 6 is connected to the temporary pole 41 using the new installation side fixing part 464 and the new installation side connecting part 465. Two new installation side fixing parts 464 constituting the connecting member 46 are fixed to the new antenna unit 6 at the same vertical positions as the two central and lower temporary pole fixing parts 462 out of the three temporary pole fixing parts 462. The upper new installation side fixing part 464 is fixed to a part of the new antenna pole 61 above the new antenna 62, and the lower new installation side fixing part 464 is fixed to a part of the new antenna pole 61 below the new antenna 62. As shown in FIG. 5, the new installation side fixing part 464 has a band 464a capable of fastening the new antenna pole 61 and a mounting plate 464b protruding from the band 464a to one side in the horizontal direction. The newly-installed fixed portion 464 is attached to the newly-installed antenna pole 61 so that the mounting plate 464b projects toward the temporary pole 41.

[0042] 4, the temporary-pillar fixing part 462 and the new-installation-side fixing part 464, which are at the same position in the up-down direction, are connected by two new-installation-side connecting parts 465 constituting the connecting member 46. The new-installation-side connecting parts 465 are made of a long angle material, a flat plate, etc. As shown in FIG. 5, one end of the new-installation-side connecting part 465 is bolted to the mounting plate 462c of the temporary-pillar fixing part 462, and the other end is bolted to the mounting plate 464b.

[0043] After the first pulling-up step S12, the attitude adjustment step S13 is carried out. Fig. 6 is a cross-sectional view taken along line AA in Fig. 4 after the attitude adjustment step S13. In Figs. 5 and 6, members for attaching the existing antenna 22 to the existing antenna pole 21 and members for attaching the new antenna 62 to the new antenna pole 61 are omitted. Fig. 7 is a front view of the upper part of the tower 1 showing the state after the attitude adjustment step S13.

[0044] The attitude adjustment step S13 is a step of loosening the band 464a and rotating the new antenna unit 6 about a rotation axis extending in the vertical direction to adjust it to a desired attitude. As shown in Fig. 6, in the attitude adjustment step S13, the attitude of the new antenna unit 6 is adjusted so that the arrangement of the new antenna 62 when viewed from the vertical direction is point-symmetrical with the existing antenna 22 about the central axis C of the temporary pole 41. As a result, when the new antenna unit 6 and the existing antenna unit 2 revolve 180° about the temporary pole 41 and exchange their positions in the rotation exchange step S24 described later, the orientation (i.e., directivity) of the existing antenna 22 of the existing antenna unit 2 before the exchange and the orientation (i.e., directivity) of the new antenna 62 of the new antenna unit 6 after the exchange become the same.

[0045] In the attitude adjustment process S13, the attitude of the new antenna unit 6 is adjusted based on the positional relationship between a predetermined bolt insertion hole 612 formed in the flange 611 of the new antenna pole 61 and the mounting plate 464b, and the positional relationship between a predetermined bolt insertion hole 212 formed in the flange 211 of the existing antenna pole 21 and the mounting plate 461b. This will be described below.

[0046] First, as shown in FIG. 5, in this embodiment, the relative positional relationship between the multiple bolt insertion holes 612 and the new antenna 62 in the circumferential direction of the new antenna unit 6 is the same as the relative positional relationship between the multiple bolt insertion holes 212 and the existing antenna 22 in the circumferential direction of the existing antenna unit 2.

[0047] As shown in Fig. 5, when the orientation of the existing antenna 22 and the orientation of the new antenna 62 are aligned, the bolt insertion hole 212 located in a predetermined direction (diagonally downward right in the example of Fig. 5) from the center of the existing antenna pole 21 of the existing antenna unit 2 is defined as the existing side specific hole 212a. When the orientation of the existing antenna 22 and the orientation of the new antenna 62 are aligned, the bolt insertion hole 612 located in the same direction as the predetermined direction (diagonally downward right in the example of Fig. 5) from the center of the new antenna pole 61 of the new antenna unit 6 is defined as the new side specific hole 612a. The angle between the existing side specific hole 212a and the mounting plate 461b when viewed from the top and bottom direction, which is an angle formed on one side of the existing side specific hole 212a in the circumferential direction of the existing antenna unit 2 (counterclockwise side in this embodiment), is defined as the existing side angle θ1. The angle between the center of the new-installation side specific hole 612a and the mounting plate 464b when viewed from the top and bottom, and the angle made on one side (i.e., the counterclockwise side) of the new-installation side specific hole 612a in the circumferential direction of the new antenna unit 6, is defined as the new-installation side angle θ2.

[0048] In the attitude adjustment process S13, the rotational attitude of the new antenna unit 6 is adjusted so that the new-side angle θ2 coincides with the existing-side angle θ1, as shown in Figures 5 and 6. As a result, the arrangement of the new antenna 62 when viewed from above and below becomes point-symmetrical with the existing antenna 22, centered on the central axis C of the temporary pole 41, as shown in Figures 6 and 7. After the attitude of the new antenna unit 6 is adjusted, the new-side fixing part 464 is tightened and fixed to the new antenna unit 6, and the attitude adjustment process S13 is completed.

[0049] It should be noted that the outer shape of the existing antenna 22 and the outer shape of the new antenna 62 viewed from the top-bottom direction after the attitude adjustment step S13 do not need to be completely point-symmetrical about the central axis C of the temporary pole 41. In other words, the arrangement of the new antenna 62 viewed from the top-bottom direction is point-symmetrical with respect to the existing antenna 22 about the central axis C of the temporary pole 41 as long as the orientation of the existing antenna 22 of the existing antenna unit 2 before replacement is similar to the orientation of the new antenna 62 of the new antenna unit 6 after replacement. For example, when the panel 221 of the existing antenna 22 and the panel 621 of the new antenna 62 are different in size, the outer shape of the existing antenna 22 and the outer shape of the new antenna 62 after the attitude adjustment step S13 are not completely point-symmetrical about the central axis C, but it is sufficient that the orientation of the existing antenna 22 of the existing antenna unit 2 before replacement and the orientation of the new antenna 62 of the new antenna unit 6 after replacement are aligned.

[0050] When the attitude adjustment step S13 is completed, the preparation work S1 is completed.

[0051] (Suspended work S2) After the preparation step, the suspension work S2 is carried out during the suspension of terrestrial television broadcasting, such as at night. In the suspension work S2, the second pulling-up step S21 is carried out first. Fig. 8 is a front view of the upper part of the tower 1 showing the state after the second pulling-up step S21.

[0052] In the second lifting step S21, first, the two new-side connecting parts 465 are detached from the two central and lower mounting plates 462c of the three temporary pole fixing parts 462. Next, the small winding device 49b is used to lift up the new antenna unit 6, and the upper end position of the new antenna unit 6 is aligned with or near the upper end position of the existing antenna unit 2. At this time, it is preferable that the lower end position of the new antenna unit 6 is positioned above the lower end position of the existing antenna unit 2 so that the new antenna unit 6 does not interfere with the antenna installation part 12 in the rotation replacement step S24 described later.

[0053] Next, the connecting step S22 is carried out. In the connecting step S22, the mounting plate 462c of the temporary-pole fixing part 462 located at the upper side of the three temporary-pole fixing parts 462 and the mounting plate 464b of the new-installation-side fixing part 464 located at the upper side of the two new-installation-side fixing parts 464 are connected using the new-installation-side connecting part 465. Furthermore, the mounting plate 462c of the temporary-pole fixing part 462 located at the center of the three temporary-pole fixing parts 462 and the mounting plate 464b of the new-installation-side fixing part 464 located at the lower side of the two new-installation-side fixing parts 464 are connected using the new-installation-side connecting part 465. As described above, the vertical distance L1 (see FIG. 3) from the temporary pole fixing part 462 at the central position to the temporary pole fixing part 462 at the top position is equal to the vertical distance L2 (see FIG. 3) from the temporary pole fixing part 462 at the central position to the temporary pole fixing part 462 at the bottom position, so the new installation side fixing part 464 and the temporary pole fixing part 462 can be connected without changing the vertical distance between the two new installation side fixing parts 464. Also, as described above, the new installation side fixing part 464 is fixed to the new antenna pole 61 after the posture is adjusted in the posture adjustment process S13, so that the mounting plate 464b of the new installation side fixing part 464 and the mounting plate 462c of the temporary pole fixing part 462 are reconnected at the new installation side connecting part 465, so that the rotation posture of the new antenna unit 6 becomes the same as the rotation posture adjusted in the posture adjustment process S13.

[0054] The second pulling-up step S21 and the connecting step S22 may be started immediately before the interruption of the terrestrial television broadcasting if it is determined that there is little influence on the terrestrial television broadcasting.

[0055] Next, a removal step S23 is performed. The removal step S23 is a step of removing the existing antenna unit 2 from the antenna installation section 12. At this time, although not shown in the figure, the coaxial cable connected to the power distributor provided in the existing antenna unit 2 is also removed.

[0056] Next, as shown by the arrow in FIG. 8, a rotational replacement step S24 is performed. FIG. 9 is a front view of the upper part of the tower 1 showing the state after the rotational replacement step S24. The rotational replacement step S24 is a step of revolving the existing antenna unit 2 and the new antenna unit 6 using the temporary equipment 4 to replace them. In this embodiment, the temporary pole 41 is rotated about its axis with respect to the mounting parts 51 and 52, so that the entire temporary equipment 4 is rotated about the temporary pole 41, thereby revolving the new antenna unit 6 and the existing antenna unit 2 suspended from the temporary equipment 4 to replace their positions. When the new antenna unit 6 and the existing antenna unit 2 are revolved in the rotational replacement step S24, the new antenna unit 6 is held (hanging) on ​​the temporary equipment 4 by the new side wire 45, and the existing antenna unit 2 is held (hanging) on ​​the temporary equipment 4 by the existing side wire 44. Furthermore, in the rotation and replacement process S24, as explained in the above-mentioned connection process S22, since the existing antenna unit 2 and the new antenna unit 6 are each fixed to the temporary pillar 41 by a connecting member 46, swinging of the existing antenna unit 2 and the new antenna unit 6 during rotation is suppressed.

[0057] Then, when the existing antenna unit 2 and the new antenna unit 6 have been revolved 180° around the temporary pole 41, that is, when the new antenna unit 6 has been rotated up to above the antenna installation section 12, an installation step S25 is performed in which the new antenna unit 6 is lowered to the antenna installation section 12 and attached. FIG. 10 is a front view of the upper part of the tower 1 showing the state after the installation step S25. In the installation step S25, the new side connecting parts 465 are removed from the upper and lower connecting members 46, and then the new antenna unit 6 is lowered to the antenna installation section 12 and attached. Although not shown, in the installation step S25, a new coaxial cable other than the coaxial cable attached to the existing antenna unit 2 is connected to a power distributor provided in the new antenna unit 6.

[0058] Next, the inspection process S26 is carried out. FIG. 11 is a front view of the upper part of the steel tower 1 showing the state during the inspection process S26. The inspection process S26 is a process of performing a characteristic confirmation inspection using the new antenna unit 6 newly installed on the steel tower 1. Prior to the characteristic confirmation inspection, the winch wire 40 is wound up by the winch 10, and the existing side wire 44 is removed from the small winding device 49a. Then, after the existing side connecting parts 463 are removed from each of the two connecting members 46 connecting the existing antenna unit 2 to the temporary pole 41, the winch 10 is rewound, and the existing antenna unit 2 is lowered to a position above the ground that is not affected by the radio waves emitted by the new antenna unit 6, and is placed on standby.

[0059] In the inspection step S26, the test radio wave 7 is transmitted using the newly installed antenna unit 6, and it is determined in step S27 whether the reception level of the test radio wave 7 meets or exceeds the reference level. If it is determined in the inspection step S26 that the reception level of the test radio wave 7 transmitted from the newly installed antenna unit 6 is below the reference level, a switchback step S28 is performed to return the existing antenna unit 2 to the antenna installation section 12 within a short period of time before the resumption of terrestrial digital television broadcasting. In the switchback step S28, the same steps as the second lifting step S21, the connection step S22, the removal step S23, the rotation replacement step S24, and the installation step S25 described above are performed. After the switchback step S28, the post-operation S3 is performed. In addition, if it is determined in the inspection step S26 that the reception level of the test radio wave 7 transmitted from the newly installed antenna unit 6 is above the reference level, the post-operation S3 is performed following the inspection step S26.

[0060] (Post-operation S3) In the post-work S3, first, the lowering step S31 is performed. FIG. 12 is a front view of the upper part of the tower 1 showing the state during the lowering step S31. The lowering step S31 is a step of lowering one of the existing antenna unit 2 and the new antenna unit 6, which is not attached to the antenna installation part 12, to the ground 100. That is, when the reception level of the test radio wave 7 emitted from the new antenna unit 6 is determined to be below the reference level in the inspection step S26 and the switchback step S28 is performed, the new antenna unit 6 is lowered to the ground 100 in the lowering step S31, while when the level of the radio wave emitted by the new antenna unit 6 is determined to be equal to or higher than the reference level in the inspection step S26, the existing antenna unit 2 is lowered to the ground 100 in the lowering step S31. FIG. 12 shows an example in which the existing antenna unit 2 is lowered to the ground 100.

[0061] As shown in FIG. 12, when the existing antenna unit 2 is lowered to the ground 100 in the lowering step S31, the two new-side fixing parts 464 and the upper and central two temporary pole fixing parts 462 among the three temporary pole fixing parts 462 are connected in advance using the two new-side connecting parts 465. At this time, if the vertical heights of the new-side fixing parts 464 and the temporary pole fixing parts 462 to be connected are not the same, one is adjusted to the height of the other before the new-side fixing parts 464 and the temporary pole fixing parts 462 are connected. After that, the existing antenna unit 2 is lowered to the ground 100 using the winch 10. In the lowering step S31, when the cutting back step S28 is performed in advance and the new antenna unit 6 is lowered to the ground 100, the new antenna unit 6 is lowered to the ground 100 in a state in which the temporary pole 41 is connected to the existing antenna unit 2.

[0062] Next, a dismantling process S32 is carried out. The dismantling process S32 is a process in which the temporary equipment 4 is dismantled and lowered to the ground 100. In the dismantling process S32, for example, the temporary equipment 4 is disassembled in the reverse order to the temporary installation process S11, and each part is lowered to the ground 100. At this time, the lightning rod 3 removed from the temporary equipment 4 is moved to the upper flange 611 of the new antenna pole 61 of the new antenna unit 6. As described above, the antenna replacement method according to the present embodiment is carried out.

[0063] (Functions and Effects of the First Embodiment) The antenna replacement method in this embodiment includes a rotational replacement step S24 of revolving the existing antenna unit 2 and the new antenna unit 6 around the temporary pole 41. Therefore, the replacement work of the existing antenna unit 2 and the new antenna unit 6 can be performed in a short period of time.

[0064] In addition, in the rotation replacement step S24, the temporary facility 4 is rotated about the temporary pole 41, thereby revolving the newly installed antenna unit 6 and the existing antenna unit 2 suspended from the temporary facility 4. For example, it is possible to configure the temporary facility 4 so that it can partially rotate about the temporary pole 41, but by making the temporary facility 4 rotatable about the temporary pole 41 as in this embodiment, the rotation replacement step S24 can be performed while the temporary facility 4 has a simple configuration.

[0065] In addition, in the rotational replacement step S24, the new antenna unit 6 and the existing antenna unit 2 are revolved in a state in which the temporary pole 41 is connected to each of the existing antenna unit 2 and the new antenna unit 6 by the connecting member 46. Therefore, during the rotational replacement step S24, the new antenna unit 6 and the existing antenna unit 2 are prevented from shaking and causing a decrease in workability.

[0066] Furthermore, the antenna replacement method of this embodiment includes an attitude adjustment step S13 for adjusting the attitude of the new antenna unit 6 before the rotational replacement step S24 so that the position of the new antenna 62 when viewed from the top and bottom is point-symmetric with the existing antenna 22 about the central axis C of the temporary pole 41. Therefore, in the rotational replacement step S24, by revolving the existing antenna unit 2 and the new antenna unit 6, it is easy to align the attitude of the existing antenna 22 of the existing antenna unit 2 before replacement with the attitude of the new antenna 62 of the new antenna unit 6.

[0067] Furthermore, a lightning rod mounting portion is formed at the upper end of the temporary pole 41, to which the lightning rod 3 that was attached to the upper end of the existing antenna pole 21 can be attached. During the antenna replacement work, the lightning rod 3 is moved from the existing antenna pole 21 to the lightning rod mounting portion of the temporary pole 41, and after the antenna replacement work, the lightning rod 3 is moved from the lightning rod mounting portion of the temporary pole 41 to the upper end of the newly installed antenna unit 6. Therefore, the same lightning rod 3 can be used during and after the antenna replacement work.

[0068] Furthermore, after the mounting process S25, the existing antenna unit 2 is kept on standby above the ground while a characteristic confirmation test is being performed using the newly installed antenna unit 6. Therefore, even if the test result is unacceptable and it is necessary to perform the cutting back process S28, the cutting back process S28 can be performed in a shorter time than if the existing antenna 22 was lowered to the ground 100 during the inspection process S26.

[0069] As described above, according to the present embodiment, it is possible to provide an antenna replacement method and temporary equipment that can shorten the work time required for antenna replacement.

[0070] [Second embodiment] FIG. 13 is a front view of the upper part of the steel tower 1 to which the existing antenna unit 2 is attached in this embodiment. In this embodiment, the steel tower 1 to which the existing antenna unit 2 and the new antenna unit 6 are attached is made of a steel pipe pole 13 that does not have a frame structure (see reference numeral 11 in FIG. 1, etc.) as shown in the first embodiment, unlike the first embodiment. The steel tower 1 in this embodiment has a plurality of steel pipe poles 13 that are stacked in the vertical direction. The steel pipe poles 13 adjacent to each other in the vertical direction are fastened with bolts at 131 formed on the steel pipe poles 13. The lowermost one of the plurality of steel pipe poles 13 is fixed to a base portion 14 buried in the ground 100. The uppermost one of the plurality of steel pipe poles 13 constitutes the antenna installation portion 12. The flange 211 formed at the lower end of the existing antenna unit 2 is stacked and fastened with bolts to the flange 131 formed at the upper end of the uppermost steel pipe pole 13 of the plurality of steel pipe poles 13. Further, intermediate positions of the plurality of steel pipe poles 13 are supported by a support pole 15 fixed to a base portion 14 buried in the ground 100. In this embodiment, an attachment portion (e.g., see reference numerals 51 and 52 in Figs. 3, 4, 7 to 12) similar to that of the first embodiment is fixed to the upper portion of the plurality of steel pipe poles 13, a temporary facility (e.g., see reference numeral 4 in Figs. 3, 4, 7 to 12) similar to that of the first embodiment is attached to the attachment portion, and an antenna replacement method similar to that of the first embodiment is carried out.

[0071] The other configurations of this embodiment are similar to those of the first embodiment. In addition, among the symbols used in the second and subsequent embodiments, the same symbols as those used in the previously described embodiments represent the same components, etc. as those in the previously described embodiments, unless otherwise specified.

[0072] (Functions and Effects of the Second Embodiment) This embodiment also has the same functions and effects as the first embodiment.

[0073] (Summary of the embodiment) Next, the technical ideas grasped from the above-described embodiment will be described by using the reference numerals and the like in the embodiment. However, the reference numerals and the like in the following description do not limit the components in the claims to the members and the like specifically shown in the embodiment.

[0074] [1] An antenna replacement method for replacing an existing antenna unit 2 having an existing antenna 22 attached to an existing antenna pole 21, which is installed at an antenna installation section 12 located at the top of a steel tower 1, with a new antenna unit 6 having a new antenna 62 attached to a new antenna pole 61, the antenna replacement method comprising: a temporary installation process S11 for forming a temporary facility 4 having a temporary pole 41 attached to the steel tower 1 and extending in the vertical direction; a rotational replacement process S24 for holding the existing antenna unit 2 and the new antenna unit 6 removed from the antenna installation section 12 using the temporary facility 4 and revolving the existing antenna unit 2 and the new antenna unit 6 around the temporary pole 41; and an installation process S25 for attaching the new antenna unit 6 arranged above the antenna installation section 12 by the rotational replacement process S24 to the antenna installation section 12.

[0075] [2] The temporary pole 41 is rotatably attached to the tower 1, and in the rotational replacement process S24, the temporary equipment 4 is rotated around the temporary pole 41, thereby causing the newly installed antenna unit 6 and the existing antenna unit 2 suspended from the temporary equipment 4 to revolve in an antenna replacement method as described in [1].

[0076] [3] In the rotational replacement process S24, the temporary pole 41, the existing antenna unit 2, and the new antenna unit 6 are connected to each other by a connecting member 46, and the new antenna unit 6 and the existing antenna unit 2 revolve in an antenna replacement method described in [1] or [2].

[0077] [4] The antenna replacement method described in any one of [1] to [3], further comprising an attitude adjustment process S13 of adjusting the attitude of the newly installed antenna unit 6 so that the arrangement of the newly installed antenna 62 when viewed from the top and bottom is point-symmetric with respect to the existing antenna 22, centered on the central axis of the temporary pillar 41, before the rotational replacement process S24.

[0078] [5] An antenna replacement method described in any one of [1] to [4], in which a lightning rod mounting section is formed at the upper end of the temporary pole 41, to which the lightning rod 3 that was attached to the upper end of the existing antenna pole 21 can be attached, and during the antenna replacement work, the lightning rod 3 is moved from the existing antenna pole 21 to the lightning rod mounting section of the temporary pole 41, and after the antenna replacement work, the lightning rod 3 is moved from the lightning rod mounting section of the temporary pole 41 to the upper end of the newly installed antenna unit 6.

[0079] [6] An antenna replacement method described in any one of [1] to [5], wherein after the installation process S25, the existing antenna unit 2 is made to wait above the ground while a characteristic confirmation test is being performed using the newly installed antenna unit 6.

[0080] [7] A temporary facility 4 used when replacing an existing antenna unit 2 having an existing antenna 22 attached to an existing antenna pole 21, which is installed at an antenna installation section 12 located at the top of a steel tower 1, with a new antenna unit 6 having a new antenna 62 attached to a new antenna pole 61, the temporary facility 4 comprising a temporary pole 41 extending in the vertical direction and attachable to the steel tower 1, the temporary facility 4 being configured to be able to hold both the existing antenna unit 2 removed from the antenna installation section 12 and the new antenna unit 6, and the temporary pole 41 being attached to the steel tower 1 so as to be rotatable about its axis.

[0081] [8] The temporary facility 4 described in [7], further comprising connecting members 46 that connect the temporary pole 41 to each of the existing antenna unit 2 and the new antenna unit 6.

[0082] (Additional Note) Although the embodiment of the present invention has been described above, the invention according to the claims is not limited to the above embodiment. It should be noted that not all of the combinations of features described in the embodiment are essential to the means for solving the problems of the invention. The present invention can be modified appropriately without departing from the spirit of the invention. [Explanation of symbols]

[0083] 1. Steel tower 12…Antenna installation section 2...Existing antenna unit 21…Existing antenna pole 22…Existing antenna 3…Lightning rod 4. Temporary facilities 41...Temporary pillar 46...Connecting member 6…New antenna unit 61…New antenna pole 62…New antenna S11: Temporary construction process S13…Posture adjustment process S24…Rotation and replacement process S25…Installation process

Claims

1. An antenna replacement method for replacing an existing antenna unit having an existing antenna attached to an existing antenna pole, which is installed in an antenna installation section located at the top of a steel tower, with a new antenna unit having a new antenna attached to a new antenna pole, comprising: A temporary installation process for forming a temporary facility having a temporary pole attached to the steel tower and extending in a vertical direction; a rotational replacement process in which the existing antenna unit and the new antenna unit removed from the antenna installation section are held by the temporary facility, and the existing antenna unit and the new antenna unit are revolved around the temporary pole; and an installation step of installing the newly installed antenna unit disposed above the antenna installation part by the rotational replacement step to the antenna installation part. How to replace the antenna.

2. The temporary pole is attached to the steel tower so as to be rotatable on its axis, In the rotating and replacing step, the temporary equipment is rotated around the temporary pole, so that the new antenna unit and the existing antenna unit suspended from the temporary equipment are revolved. The antenna replacement method according to claim 1 .

3. In the rotational replacement process, the temporary pole, the existing antenna unit, and the new antenna unit are connected to each other by a connecting member, and the new antenna unit and the existing antenna unit are revolved. The antenna replacement method according to claim 1 or 2.

4. The method further includes a posture adjustment step of adjusting the posture of the new antenna unit so that the position of the new antenna when viewed from above and below is point-symmetric with respect to the central axis of the temporary pole before the rotation replacement step. The antenna replacement method according to claim 1 or 2.

5. A lightning rod mounting portion is formed at the upper end of the temporary pole, to which the lightning rod attached to the upper end of the existing antenna pole can be attached, During the antenna replacement work, the lightning rod is moved from the existing antenna pole to the lightning rod mounting portion of the temporary pole, After the antenna replacement work, the lightning rod is moved from the lightning rod mounting portion of the temporary pole to the upper end of the newly installed antenna unit. The antenna replacement method according to claim 1 or 2.

6. After the mounting step, the existing antenna unit is made to wait above ground level while a characteristic confirmation test is being performed using the new antenna unit. The antenna replacement method according to claim 1 or 2.

7. A temporary facility used when replacing an existing antenna unit, which is installed in an antenna installation section located at the top of a steel tower and has an existing antenna attached to an existing antenna pole, with a new antenna unit, which is installed in a new antenna pole and has a new antenna attached to a new antenna pole. A temporary pole extending in the vertical direction and attachable to the steel tower is provided, the temporary facility is configured to be able to hold both the existing antenna unit detached from the antenna installation section and the newly installed antenna unit, The temporary pole is rotatably attached to the tower. Temporary facilities.

8. Further provided is a connecting member that connects the temporary pole to each of the existing antenna unit and the newly installed antenna unit. The temporary facility according to claim 7.

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