JPH0254962B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a reflector for a parabolic antenna for receiving satellite broadcasting, and its purpose is to
An object of the present invention is to provide a reflector for a parabolic antenna for satellite broadcast reception in which a device placed near the focal point of the antenna, such as a primary radiator, is not damaged by solar heat.

As is well known, the satellite broadcasting satellite BS-2A is located at a distance of approximately 35,800 km above the equator at 110 degrees east longitude. On the ground, the reflector of a parabolic antenna or offset parabolic antenna (in this specification, these antennas are collectively referred to as parabolic antennas) is pointed in the direction of this broadcasting satellite, and the radio waves from the satellite are reflected by this reflector. Collect in the primary radiator. However, as shown in Figure 1, the arrival direction A of the radio waves from the broadcasting satellite 1 toward Japan 3 on the earth 2 and the arrival direction B of the solar rays from the sun S coincide on the vernal and autumnal equinoxes. It happens several days a year nearby. In such a case,
Like broadcast radio waves, sunlight also gathers on the primary radiator, and as a result, the focal point of the primary radiator's aperture and its surroundings will be 100 to 200 degrees Celsius in the case of an offset parabolic antenna with a minor axis diameter of 75 cm. There is also a risk of overheating. The present invention provides a reflector for a parabolic antenna for satellite broadcast reception in which the primary radiator or its surrounding area is not exposed to high heat.

Embodiments of the present application will be described below with reference to the drawings.

FIG. 2 is a perspective view of a satellite broadcast receiving parabolic antenna, and FIG. 3 is a cross-sectional view taken along line D-D' of a reflecting mirror. 4 is a reflector of the antenna that reflects 12 GHz broadcast radio waves and focuses them on the focal point where the primary radiator is placed, while diffusely reflecting sunlight. On the surface C of the reflecting mirror 4 on the radio wave arrival side, a diffuse reflection surface 12 is formed which is coated with matte paint over the entire surface or almost the entire surface. Reference numeral 10 indicates a radio wave reflecting material formed of a wire mesh or sheet of a good conductor, and 10 indicates a synthetic resin that protects the reflecting material 10. Next, 5 indicates the primary radiator,
The opening 15 is directed toward the reflecting mirror 4 described above.
Reference numeral 14 denotes a waterproof device, and the opening 15 is appropriately provided with a cover or cap made of a synthetic resin material that has extremely low loss and is inexpensive for the passage of broadcast radio waves. The waterproofing device 14 prevents rainwater from entering the inside of the primary radiator (also into the converter circuit described below) through the opening 15. 6 is a BS converter housing, which converts the satellite broadcasting radio waves collected in the primary radiator 5 to lower frequencies convenient for transmission, e.g.
It has a built-in frequency conversion circuit board and electronic components for converting to a 1.3GHz intermediate frequency signal.
The housing 6 has a well-known structure to ensure sufficient waterproofness. A support arm 7 maintains the positional relationship between the reflecting mirror 4 and the primary radiator 5. Reference numeral 8 denotes a fixture, which is attached to a support 9 installed on the roof or on the ground, and is used to orient the reflector 4 toward the satellite. Incidentally, a dashed line 16 indicates a part of the arrival path of the radio waves.

In the parabolic antenna for receiving satellite broadcasting as described above, radio waves from satellite broadcasting are transmitted through the reflecting material 1 of the reflecting mirror 4.
0, is focused toward the focal point of the primary radiator 5, and is subjected to electrical processing for normal reception.

On the other hand, even if sunlight overlaps with the arrival direction of radio waves as shown in FIG. 1, the sunlight arriving at the reflecting mirror 4 is diffusely reflected by the diffuse reflection surface 12, and is prevented from converging at a specific position. Therefore, it is possible to prevent inconveniences such as heating the primary radiator or its surroundings, melting and damaging the waterproofing device 14, or causing a loss of mechanical accuracy of the primary radiator 5 due to linear expansion, etc. It is also possible to prevent the electrical performance of the converter etc. connected to 5 from being disturbed.

In addition, although we have described the parabolic antenna installed above, when aligning the direction of the reflector 4 when installing the antenna, even if the worker accidentally leaves the reflector facing the sun, the primary radiator It is also possible to prevent the waterproofing device 14 provided in the opening 15 of 5 from melting due to heat, forming holes and losing its waterproof properties.

Next, FIG. 4 is a cross-sectional view showing a different example of the reflecting mirror 4. Components having the same functions as those in the previous figure are indicated by the same reference numerals with the letter "e" added thereto, and redundant explanation will be omitted. Reference numeral 13 denotes a diffusely reflective surface (rough surface, also referred to as a pear surface) which is created by scraping the entire surface of the resin layer 11e or by providing it at the same time as molding.

Figure 5 is an enlarged end view of the E-E' portion of Figure 3;
The figures each show an enlarged end view of the F-F' portion of FIG. 4. The same members as those in the previous figure are designated by the same reference numerals.

As described above, the present invention has the effect that the reflecting mirror 4 can collect radio waves of satellite broadcasting onto the primary radiator without any trouble.

Furthermore, even if the direction of the broadcasting satellite and the sun were to overlap, the diffusely reflecting surface prevents the primary radiator or its surrounding components from being damaged or distorted by heat.

[Brief explanation of the drawing]

The drawings show examples, and Figure 1 is an explanatory diagram showing the overlap of the directions of satellite broadcasting radio waves and sunlight;
Fig. 2 is a perspective view of the parabolic antenna, Fig. 3 is a sectional view taken along line D-D' of the reflector, Fig. 4 is a sectional view of a different reflector, and Fig. 5 is a partially enlarged end view taken along line E-E' of Fig. 3. ,
FIG. 6 is an enlarged end view of the section F-F' in FIG. 4. 4...Reflector, 5...Primary radiator, 10...Reflector, 12...Diffuse reflecting surface.

Claims (1)

[Claims] 1. In the reflector of a parabolic antenna for satellite broadcasting, which is equipped with a reflective material for concentrating radio waves arriving from a satellite toward a focal point, the surface on the radio wave arrival side is provided with a diffused reflection surface that diffusely reflects light rays from the sun, etc. A reflector for a parabolic antenna for receiving satellite broadcasting, characterized by: