JPH0135530B2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to an omnidirectional antenna that can be used by people who are usually called amateur radio operators to selectively communicate with other stations located in unspecified locations. be.

With this type of omnidirectional antenna, when communicating with other stations in all directions around the own station, since the antenna is omnidirectional, it is possible to freely communicate with stations in any direction. It has its features. However, this becomes a significant drawback when communicating with a specific station in one direction. That is, when communicating with a specific station, there is a drawback that the signal level value of the antenna (the level value of the transmitted signal and the received signal) cannot be significantly improved only for communication with that specific station.

To solve this problem, there are some antennas that support a directional antenna, such as a Yagi antenna, with a support, and by rotating the support, the directional direction of the antenna can be changed. Although this device has the feature of giving a large directivity to a specific station, on the other hand, if you try to start communication with the other station while the antenna is facing in a direction different from that of the other station. In this case, even if the receiver is set to the transmission frequency of the other station, there is no other station in the receiving direction of the directional antenna, so there is a problem that the receiver cannot pick up the signal of the desired other station at all.

To solve this problem, four unipole radiating elements are arranged and fixed at equal intervals on the circumference of an appropriate number of radii centered on the origin, and the received signal obtained from each element is switched. Diversity receiving devices for use are provided (for example, Japanese Patent Application Laid-Open No. 1973-
(See Publication No. 105253). However, if the positions of the four radiating elements are fixed, for example in the state shown in Figure 3, if the positions of the radiating elements are fixed at each position of 0°, 90°, 180°, and 270°, then -3dB, -7.5dB, -
Although it is possible to check the relative levels of 4 dB and -2 dB, it has the disadvantage that checking other levels is not possible. That is, there is a major problem in that it is impossible to detect a relative level of 0 dB that exists at a position of 105°, 230°, or 300° and communicate at that preferred level. Furthermore, in order to solve this problem, it is possible to increase the number of elements from 4 to 8 or 12, but this would increase the uneconomical effect, and due to the correlation between elements, each element would have no directivity. Performance is drastically reduced. VSWR becomes significantly worse. The frequency band used becomes extremely narrow. Other problems such as this occur.

Therefore, the present invention establishes an omnidirectional antenna which has the property of being able to communicate with any of unspecified radio stations scattered in all directions at any time as long as the frequency of the receiver is selected. When you want to start communicating with a desired station, you can start communication immediately by simply setting the receiver to the frequency emitted by the desired station, and after starting communication, you can continue communication while maintaining that state. By rotating the omnidirectional antenna around the pillar and stopping it at the position where the signal level value of the omnidirectional antenna is highest, amateur radio operators are able to communicate with high efficiency from then on. The purpose of the present invention is to provide an omnidirectional antenna for communications that can provide revolutionary convenience to the public.

The drawings showing the embodiments of the present application will be described below. In FIGS. 1 and 2, reference numeral 1 designates a well-known antenna tower, which is composed of legs 2 erected from the ground and a mounting base 3 attached to the tips of the legs 2. Reference numeral 4 indicates an antenna rotator fixed to the mounting base 3, and reference numeral 5 indicates its rotation drive unit. Reference numeral 6 indicates a support column fixed to the rotary drive unit 5. Reference numeral 7 denotes a lifting arm extending horizontally from the support 6, and is fixed to the support 6 with a U-bolt 8 and a nut 9. 10 is an omnidirectional antenna, and a U bolt 1 is attached to the tip of the arm 7.
1 and nuts 12. The Brown antenna is shown as an example of this omnidirectional antenna, but any other VHF or
A UHF omnidirectional antenna can be used. Reference numeral 13 denotes a feed line having one end connected to the antenna 10, using a coaxial cable, and the other end connected to, for example, a transmitter/receiver installed indoors. Reference numeral 14 indicates a stopper for fixing the power supply line 13 to the mounting base 3.

Next, how to use the above configuration will be explained. First, as is well known, the frequency of the transmitter and receiver is matched to the frequency with which communication is to be performed. For example, amateur radio stations use the 144MHz band for VHF, or the 435MHz band for UHF. Then, as is well known, communication is carried out with the target station. Once contact with the target station has been established in this manner, the rotary drive section of the antenna rotator 4 is then rotated by a remote control device for the antenna rotator 4 placed near the transmitter/receiver. Then, the antenna 10 rotates around the column 6 using the length R of the extending arm 7 as a radius. It is best to perform this operation while communicating with the target station. and the position where the level of the signal from the target station received by the antenna 10 is the strongest;
Alternatively, the rotation of the antenna rotator is stopped at the position where the level of the signal sent from the antenna 10 toward the target station is the highest. Once such a state is reached, all that is left to do is to communicate with the target station as usual.

Furthermore, the above structure can be used in the following manner. In other words, when communicating between your own station and two partner stations, three stations in total, one of the partner stations is, for example, several tens of kilometers away and the other several kilometers in the suburbs, the antenna 10 is placed on a support. 6 to an appropriate position so that signals from distant partner stations can be received with high sensitivity and signals from nearby partner stations can be received with low sensitivity. It is also possible to communicate with nearby stations at approximately the same level, that is, in a state where communication is easy.

Next, the reason why the reception level or transmission level can be changed by rotating the antenna 10 around the support 6 as described above will be explained.

When the frequency of a radio wave reaches a high frequency such as 144 MHz or 435 MHz, its propagation path is greatly influenced by the topography, and the propagation path becomes complicated, and the direct wave is propagated with indirect waves or reflected waves interfering with each other.
Therefore, even if the position near the receiving point moves slightly, the electric field strength at each point will vary. For this reason, by rotating the antenna 10 around the pillar 6 and displacing its position,
The reception level at antenna 10 can be changed. (The same applies to the case of transmission.) This situation will be explained with reference to FIG. 2 of the drawing.
That is, in Fig. 2, the transmission point 1 is located at the upper position of the drawing.
5, if the antenna 10 is in the position shown in the figure, the signal will be received at the reception level shown (-3 dB relative level). At a position where the antenna 10 is rotated about 90 degrees in the direction of arrow A around the support 6, the reception level by the antenna 10 becomes a relative level of -7.5 dB as shown. When this antenna is further rotated in the direction of arrow A and brought to point B, antenna 1
As shown in the figure, the reception level at 0 is the relative level of OdB, that is, the highest reception level. In this situation, the antenna 10 is placed around the pillar 6.
The case of rotation is shown in Fig. 3. This figure 3 shows the relationship between the angle of rotation and the reception level at that location when the antenna 10 is rotated around the support 6 with the position shown in figure 2 being 0 degrees as a reference. This shows the results. The measurement condition data shown in FIG. 2 is that the distance between the pillar 6 and the transmitting point 15 is 15 km, the length R is 40 cm, and the frequency is 435 MHz. The pattern shown in FIG. 3 varies greatly depending on the topography of the receiving point, transmitting point, and other locations.

Further, the necessary length R of the above-mentioned extension length is determined by the frequency of the signal to be transmitted and received by the antenna 10, and by rotating the antenna 10 around the support 6, the antenna 10 can be extended. In order to obtain a preferable result, a value of 0.5 to 1 times the wavelength of the frequency used is selected as the length R so that it can be moved to positions with different electric field strengths.

For example, when determining the extension length R of a communication antenna in the 435MHz band (430-440MHz), since the wavelength of the above frequency is 0.7m to 0.68m, the above-mentioned extension length R is determined by the wavelength If you select from 0.5 to 1 times the size, you will select from 34cm to 70cm. The one in FIG. 2 shows an example in which the length R of the extension is set to 40 cm within the above range.

Next, FIG. 4 shows a different embodiment of the present invention, and shows an example in which a take-out arm 7e is rotatable with respect to a fixed support column 6e. Reference numeral 21 denotes a rotating body rotatably attached to the support 6e, which is attached to the lifting arm 7e.
The base of is fixed. 22 is a gear formed on the outer periphery of the rotating body 21, 23 is a motor attached to the support column 6e, and 24 is a pinion attached to the rotating shaft of the motor 23, which meshes with the gear 22.

In such a configuration, by operating the motor 23, the rotating body 21 rotates, and the antenna 10e rotates around the support 6e. In this embodiment, parts that are functionally the same or equivalent to those in the previous embodiment are given the same reference numerals as in the previous embodiment with an alphanumeric letter "e", and redundant explanations are omitted.

As described above, in the present invention, since the antenna 10 attached to the pillar 6 is an omnidirectional antenna, when an amateur radio operator wants to communicate with another amateur radio station, it is possible to It has the advantage of being able to communicate with those stations even if they are located in different directions.

Moreover, by using the omnidirectional antenna 10, it is possible to communicate with other stations in any direction; however, it is possible to communicate with any arbitrarily selected station. After starting, the omnidirectional antenna 10 is gently rotated around the pillar 6, and the communication level increases and decreases continuously during the rotation process. As a result, the omnidirectional antenna 10 becomes omnidirectional. While communicating at the position where the signal level value of the antenna is at its maximum (for example, the position of 105°, 230°, or 300° in Figure 3), the connection (continued) state can be maintained without missing the communication destination. This has the revolutionary effect of making it possible to freely select a station and to communicate with the selected station in the most favorable condition (that is, in the condition with the largest signal level value). This has the effect of helping to solve the fatal drawbacks that occur when rotating the conventional ``directional antenna'' mentioned above, or when switching and using signals from multiple ``fixed radiating elements.'' There is.

Of course, when communicating in a strong electric field, keep checking the communication status and adjust the signal level appropriately to suit your preference (for example, -5 dB position/
In Fig. 3, there is also the effect that comfortable communication can be achieved by searching for a signal at a level that matches your preference at any position such as 20°, 140°, etc.

[Brief explanation of drawings]

The drawings show an embodiment of the present application, and Fig. 1 is a perspective view, Fig. 2 is a plan view, Fig. 3 is an actual measurement drawing showing the relationship between the rotational position (angle) of the antenna and the reception level, and Fig. 4. 5 is a front view showing a different embodiment, and FIG. 5 is a sectional view taken along the line -. 6... Support, 7... Extended arm, 10... Antenna.

Claims (1)

[Claims] 1. It consists of a support that is erected on a fixed object, an extended arm extending laterally from the top of the support, and an omnidirectional antenna whose base is fixed to the free end of the extended arm. The omnidirectional antenna is configured to be able to rotate around the support with the radius of the extending arm, and the distance from the support to the omnidirectional antenna is equal to the distance between the support and the omnidirectional antenna. 1. An omnidirectional antenna for communication, characterized in that the antenna has a length sufficient to cause the level value of a signal to change successively during the process of rotation of the directional antenna around the post position.