JPS6298928A - Medium broadcast wave passive relay system - Google Patents

Abstract

PURPOSE:To relieve a fringe area by providing a tuning reactor between a base of an antenna and a grounding line to increase the electric field strength of a medium broadcast wave reradiated from the antenna. CONSTITUTION:The medium broadcast antenna 1 is installed vertically on the ground via an insulation post insulator 3 and a medium broadcast transmitter 5 is connected to the base of the antenna 1, then a current Ia flows to the antenna 1 by an output of the transmitter 5. Further, three sets of relaying vertical antennas 2 are installed on the ground via a post insulator 6 at an equal interval (d) on a line orthogonal in the medium broadcast wave incoming direction. A tuning reactor 8 is connected respectively to the base of each antenna 2. The tuning reactor 8 consists of a parallel resonance circuit comprising a coil L1 and a capacitor C1 and is inserted between the base of the antenna and a grounding line 10. Then the reradiation current flowing to the relaying vertical antennas 2 is amplified and the electric field strength of the medium broadcast wave reradiated from the antennas 2 is increased remarkably, the medium broadcast wave is relayed excellently and the fringe area is relieved.

Description

DETAILED DESCRIPTION OF THE INVENTION a. Field of Industrial Application The present invention relates to a medium wave broadcast wave relay system, and particularly to a relay system that is optimal for use in relaying medium wave broadcast waves to hearing-impaired areas.

b. Conventional technology and its problems Recently, the importance of medium wave broadcasting as a mass media for information transmission has been reaffirmed. However, currently there are still many areas with hearing loss.As a means to solve this problem, a plan to construct small relay stations has been proposed. However, if you try to plan the construction of a small relay station using the conventional method, problems will arise in the allocation of broadcasting frequencies, and if you try to use the same precision frequency method, problems such as beat area problems and construction cost problems will arise. come.

The present invention has been made in view of the above-mentioned circumstances, and although it is a relatively simple method, its purpose is to
It is an object of the present invention to provide a medium-wave broadcast wave unpowered relay system that can greatly increase the electric field strength of medium-wave broadcast waves relayed to hearing-impaired areas.

Means for Solving the C0 Problem In order to solve the above-mentioned problems, in the present invention, a medium wave broadcast wave relay antenna is installed in the radio wave propagation path of the medium wave broadcast wave, and the medium wave induced by this antenna is Using the induced voltage of the medium wave broadcast wave, the electric field strength of the medium wave broadcast wave re-radiated from the antenna is increased by the action of a tuning reactor inserted between the base of the antenna and the ground wire. That's what I did.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of a medium-wave broadcast wave parasitic relay system according to the present invention will be described with reference to FIGS. 1 to 5.

FIG. 1 shows the arrangement of a medium wave broadcasting antenna 1 and three relay vertical antennas 2 at a master station. As shown in FIG. 1, a medium wave broadcasting antenna 1 is erected on the ground via an insulator 3 for insulation, and is vertically supported by a plurality of branch lines 4. A medium wave broadcast transmitter 5 is connected to the base of the antenna 1, and a current 1 flows through the antenna 1 based on the output of the transmitter 5.

In addition, three relay vertical antennas 2 are erected on the ground via stand insulators 6 at positions spaced at equal intervals d on a line perpendicular to the direction of arrival of medium wave broadcast waves, and a plurality of It is supported vertically by a branch line 7 of the book. Tuning reactors 8 are connected to the bases of these antennas 2, respectively. This tuning reactor 8 is the third
As shown in figure (A), coil L1 and capacitor C2
It consists of a parallel resonant circuit, and is inserted between the base of the antenna and the ground wire 10.

In FIG. 1, Ha is the height of the medium wave broadcasting antenna 1, ■ is the height of the relay vertical antenna 2, and γ.

is a medium wave broadcasting antenna 1 and a vertical relay antenna 2 in the center.
The distance between and ψ is the angle in the horizontal plane with the direction of arrival of the medium wave broadcast wave as the axis.

FIG. 2 is for theoretically explaining the operational relationship between the medium wave broadcasting antenna 1 and the central relay vertical antenna 2. As shown in FIG. Here, considering the re-radiated electric field strength from the relay vertical antenna 2, the re-radiated electric field strength at a position separated from the antenna 2 by a distance rx is Eo. (TX), then rx Tol'b+ri0+Jx,1.

h; Antenna effective height α; Radio wave propagation loss rate R of medium wave broadcast waves; Ground loss resistance E of the above equation 0. . (y,) is maximum at the combined inductance X of the tuned reactor 8. When becomes the following value.

Xo = −Xb In this case, E, , (TX) has the following value.

-1-- A composite value E of the electric field strength re-radiated from each relay vertical antenna 2 shown in FIG.

−j+s(re +r++) jmdsin
ψ −j+wdsinψib(γ,)=ioo(γ+
1)+3 fl+e +e
ITo+T earthquake --
---・■ Here, an example of calculating the above-mentioned Eb(TX) is as shown in FIG. However, in this calculation example, the transmission frequency f = 1500 of the medium wave broadcasting antenna 1 of the parent station
[Ktlz), E, -318CmV/+n), and the height of the relay vertical antenna 2 is tlb = 20 (m).
, the distance γ between this antenna 2 and the medium wave broadcasting antenna l. -20 (Km), distance d of antenna 2 = 1. O
Cm), radio wave propagation loss rate α-'0.5 of medium wave broadcast waves
, the angle ψ−〇6.

As can be seen from Fig. 5, according to this method, the re-radiation current flowing through the relay vertical antenna 2 is increased, and as a result, the electric field strength of the medium-wave broadcast waves re-radiated from this antenna 2 is greatly increased. Increased.

By the way, when relaying multiple broadcast waves in the same manner as above, as shown in FIG. 3(B), a series circuit of coil I4 and capacitor C2, and a series circuit of coil L and capacitor C3 A synchronized phase reactor 8' is used, which is formed by connecting the two in parallel with each other. Then, for the transmission frequency f, if zb(r+) = Rb(r+)±jXb(f+), then Xo(f+) = +Xb(f+ For the transmission frequency f2, Zb(fZ) ) ± jXb (fZ), then Xo (f z) = +
In the case of 3), the circuit elements CZ, C3, and Lx are set so as to satisfy the condition that Xo(f:+) = +L, (f+).

What is necessary is to determine the capacitance and inductance of L3.

Note that if the number of broadcast waves to be relayed is larger, this can be handled by increasing the number of circuit elements.

FIG. 4 shows a relay vertical antenna 12 suitable for more economically implementing the medium wave broadcast wave relay system according to the present invention.
This shows the configuration of In FIG. 4, reference numeral 13 denotes a tower antenna, which is erected on the ground via a base insulator 14, and has a plurality of branch lines 15 indicated by broken lines.
is supported vertically by In addition, a wire antenna 16 is attached to the two branch lines 15 held on a line (a-b line) perpendicular to the radiation wave arrival direction (c-d line direction).
．． 17 have been constructed. In other words, these wire antennas 16 and 17 are bent in a dogleg shape, and the insulator 18
The inclined antenna wire sections 16a, 17a are inserted into the upper part of the branch line 15 via the antenna wires, and the vertical antenna wire sections 16b, 17b are fixed to the ground via the insulator 19 so as to be parallel to the tower antenna 13. It is composed of.

A tuning reactor 20 is connected to the base of the tower antenna 13, and a tuning reactor 2L is connected to the lower end of the vertical antenna wire portions 16b and 17b of the wire antenna 16.17.
22 are connected to each other. In addition, in FIG. 4, 23 is a grounding wire, and 24 is an insulator.

According to the relay antenna 12 having such a configuration, the tower antenna 13 and the wire antennas 16 and 17 are arranged on a line (a-bg) that is orthogonal to the broadcast wave arrival direction (c-d line direction). , it is not necessary to separately provide two tower antennas in addition to the tower antenna 13, which is very economical.

d0 Effects of the Invention As described above, the present invention utilizes the induced voltage of a medium wave broadcast wave induced in a medium wave broadcast wave relay antenna, and uses the action of a tuning reactor to generate a medium wave re-radiated from the antenna. Since the electric field strength of the broadcast wave is increased, medium wave broadcast waves can be relayed satisfactorily using a relatively simple method, and relief can be especially achieved in hearing-impaired areas.

[Brief explanation of drawings]

Fig. 1 is a perspective view schematically showing the configuration of an embodiment implementing the medium wave broadcast wave parasitic relay system according to the present invention, Fig. 2 is a schematic side view of the main parts of this embodiment, and Fig. 3 ( A) and (B)
is a circuit configuration diagram of the tuning reactor, Fig. 4 is a perspective view showing a separate vertical antenna for relaying, and Fig. 5 is a diagram showing the combined electric field strength E.
It is a graph showing an example of calculation of b(rX). 1...Antenna for medium wave broadcasting of the master station, 2.12...Vertical antenna for relay, 5...Transmitter for medium wave broadcasting, 8, 8', 21.20.22...For tuning Reactor, 10, 23...Grounding wire, 13...Tower antenna, 16, 17...String antenna, 16b, 17b...Vertical antenna line portion. Figure 1 Figure 3 (A,) (B) Figure 4

Claims (1)

[Claims] A medium-wave broadcast wave relay antenna is installed in the radio wave propagation path of medium-wave broadcast waves, and by using the induced voltage of the medium-wave broadcast waves induced in this antenna, a connection is made between the base of the antenna and the ground wire. A medium wave broadcast wave parasitic relay system characterized in that the electric field strength of medium wave broadcast waves re-radiated from the antenna is increased by the action of an inserted tuning reactor.