JPH04167706A - Snow melting device for antenna - Google Patents

Abstract

PURPOSE:To surely prevent snow deposition by stretching a part of a radome in the antenna major lobe direction with a rod member so as to prevent flaw or slack. CONSTITUTION:A primary radiator 18 and a reflecting mirror 10 or the like are covered by a bag-shaped radome 34. Moreover, a front side (in the antenna major beam direction) of the radome 34 is stretched by a rod member 28, and no flaw nor slack exists in the front side, then the water content due to rain drops or molten snow is not pooled but flows downward and snow deposition is hardly caused. Similarly, no flaw nor slack is in existence, then the hot air blown out of a hot generator 24 rises along the inner face of the front side of the radome 34 without a fault, heat dissipation is exerted uniformly to the surface and no uneven snow deposition is caused. Thus, the snow deposition to the front side of the radome 34 in the antenna major lobe direction giving adverse effect on the radio wave radiation characteristic is surely prevented.

Description

[Detailed Description of the Invention] Overview Regarding a snow melting structure for preventing snow from accumulating on parabolic antennas, Gregorian antennas, Cassegrain antennas, etc., the object is to provide a snow melting structure for antennas that can reliably prevent snow from accumulating. A radio wave radiation system for an antenna, in which a primary radiator of the antenna is attached via a stay member to the periphery of the reflector so as to have a predetermined positional relationship with respect to the reflector that forms a beam in the main direction of the antenna. In the snow melting structure of the antenna, which is formed by wrapping the stay member in a bag-like radome and providing a warm air generator for generating heat convection inside the radome, one end of the stay member is fixed near the tip of the stay member, and the other end is fixed to the stay member near the tip of the stay member. A rod-shaped member fixed near the top of the reflecting mirror is provided, and the rod-shaped member allows
A portion of the radome on the antenna main direction side is configured to be tensioned.

J7 Great usability! l'F The present invention relates to a snow melting structure that prevents snow from accumulating on parabolic antennas, Gregorian antennas, Cassegrain antennas, and the like.

In recent years, relatively small-diameter parabolic antennas, Gregorian antennas, Cassegrain antennas, etc. with reflector diameters of about 0.6 to 1.8 m have been used in satellite broadcasting, satellite communications, etc. because of their high gain and sharp beam characteristics. It has become widely used.

A parabolic antenna uses a paraboloid of revolution as a reflecting mirror surface.
A primary radiator is provided at the focal point.Cassegrain antennas and Gregorian antennas have a sub-reflector in addition to the main reflector using a paraboloid, and the Cassegrain antenna uses a hyperboloid as the sub-reflector. A Gregorian antenna uses an elliptical surface for the antenna and sub-reflector. - To avoid deterioration of radiation characteristics due to secondary radiator or sub-reflector, -
An offset type antenna is also used in which a secondary radiator or sub-reflector is placed outside the main radiation (beam) of the antenna.

These antennas are generally installed outdoors, but if snow accumulates on the -order radiator or reflector, the radio wave radiation characteristics deteriorate, so it is necessary to take measures to prevent snow accumulation.

Conventional technology As a measure to prevent snow accumulation, a heat pad was pasted on the back of a reflecting mirror or the surface of other radio wave emitting system components, and the heat from the heat pad was used to melt the snow. However, with this countermeasure, only the surface to which the beat pad is attached is heated by heat generation, which causes temperature unevenness in the parts and thermal distortion, and the heat generation capacity of the heater wire inside the heat pad is fixed, so the amount of heat generated is It had drawbacks such as being difficult to change.

For this reason, the entire radio wave emitting system including the -order radiator and reflector is covered with a bag-shaped radome to prevent snow from accumulating on them. In addition, when the antenna is covered with a bag-shaped radome like this, the angle of inclination of the radome on the antenna main direction side is generally gentle due to its structure, so there is a lot of snow accretion in this part, and this part is also (beam forming direction), and since snow accretion in this area has a particularly negative effect on radio wave radiation characteristics, a hot air generator is installed in the internal space of the radome to cause hot air to convect within the radome.
An antenna snow melting structure has been proposed that melts snow by heating the radome surface.

Problems to be Solved by the Invention However, if a bag-shaped radome is simply placed over the antenna, wrinkles and slack may be present on the radome surface (or may be caused by wind, etc.); The convection currents were disrupted, causing uneven heat radiation to the radome surface, resulting in areas where snow could not be melted. In addition, moisture from raindrops and snow melting due to the heat from the hot air generator does not flow downward and accumulates in these wrinkles and slack areas, causing further snow to accumulate and grow into lumps of ice and snow that cannot be melted. Sometimes it was difficult.

The present invention has been made in view of these points, and an object of the present invention is to provide a snow melting structure for an antenna that can reliably prevent snow from accumulating.

Means for Solving the Problem The primary radiator of the antenna is attached via a stay member to the periphery of the reflector so as to have a predetermined positional relationship with respect to the reflector that forms a beam in the main direction of the antenna. The radio wave radiation system of the antenna is wrapped in a bag-shaped radome, and a warm air generator for generating heat convection is provided inside the radome.

A rod-like member made of a non-metallic material is provided, one end of which is fixed near the tip of the stay member, and the other end is fixed near the top of the reflector, and the rod-like member allows the radome to move in the main direction of the antenna. The above-mentioned problem is solved by configuring the side part to be tensioned.

In addition, instead of the rod-shaped member, at least one wire member is stretched between the vicinity of the tip of the stay member and the peripheral edge of the reflector, and the wire member extends from the side of the radome in the antenna main direction. The above-mentioned problem can also be solved by making the part tense.

Function According to the present invention, the portion of the radome on the antenna main direction side is tightened using a rod-like member or a wire member to prevent wrinkles or loosening. Water can now flow downward without any obstruction. In addition, the front part of the bag-shaped radome (
The hot air generated by the hot air generator will flow uniformly along the inner surface of the main antenna (main direction side), and heat will be dissipated evenly.

As a result, snow accretion on the front surface of the radome can be reliably prevented, diffused reflection of radio waves, etc. can be reduced, and radio wave radiation characteristics can be improved.

Embodiments Hereinafter, embodiments of the present invention will be described with reference to the drawings.

Fig. 1 is a partially cutaway side view showing the configuration when the present invention is applied to an offset type parabolic antenna, Fig. 2 is a partially perspective view of the same, and Fig. 3 is a sectional view taken along the line a-a of Fig. 2. It is.

Reference numeral 10 denotes a parabolic reflecting mirror having a radio wave reflecting surface, and a plurality of ribs 10b are formed on the back surface of this reflecting mirror IO in order to achieve weight reduction while maintaining a predetermined strength.

The reflecting mirror 10 is supported by a support ball 14 via a mounting member 12 near the center on the back side thereof. One end of a plurality of stays 16 is fixed to the peripheral edge 10a of the reflecting mirror 100, and an LNB horn, that is, a primary radiator 18 is attached to the other end of the stay 16. They are arranged in a predetermined positional relationship with respect to each other. 20 is a protective frame for the primary radiator 18, which is fixed to the stay 16. A support member 22 is fixed to the lower part of the reflecting mirror 10, and a hot air generator 24 consisting of an air blowing fan and a heater is attached to the support member 22. 26 is a protective frame and wind direction plate for the hot air generator 24.

Reference numeral 28 denotes a rod-shaped member made of a material such as resin that does not affect radio wave characteristics, and one end of this rod-shaped member 28 is attached to the vicinity of the top of the peripheral edge 10a of the reflecting mirror 10 via a mounting bracket 30. The other end is the protective frame 20 of the primary radiator 18
is attached to. A wire member 32 is stretched across the rod-shaped member 28 and the peripheral edge 10a of the reflecting mirror 10. 34 is an opening 3 that can be expanded and contracted with a rope, etc.
The radome 34 is a bag-shaped radome having a drain hole 4a and a drain hole 34b, and the radome 34 is formed by sewing a waterproof sheet such as a woven glass cloth whose surface is coated with vinyl chloride. The radome 34 is placed over the primary radiator 18, the reflector 10, etc., and then tied with a rope or the like to keep the front portion uniformly tensioned.

Therefore, when the hot air generator 24 is activated, the hot air flows upward along the inner surface of the front portion of the radome 34, and then
It descends along the radio wave reflecting surface of the reflecting mirror 10 and is sucked into the fan and circulated. As a result, particularly the front portion of the bag-shaped radome 34 is warmed. For example, the hot air generator 24 has a temperature sensor provided outside the radome 34 and operates when the outside temperature is 2° C. or lower. Or use a snowfall detector as a radome 34
The warm air generator 24 is installed outside of the building and operates only when it snows.

According to the above-mentioned configuration, since the -order radiator 18, the reflector 10, etc. are covered with the bag-shaped radome 34, snow accretion thereon is reliably prevented, and the front side of the radome 34 (
antenna main direction side) is the rod-shaped member 28 and the wire member 32
Because there are no wrinkles or slack in this part, moisture from raindrops and melting snow does not collect but flows downward.
It's hard to get snow. In addition, since there are no wrinkles or slacks, the hot air blown out by the hot air generator 24 rises along the front inner surface of the radome 34 without any obstruction, and heat is radiated uniformly on the surface, preventing uneven snow melting. It will no longer occur. Thereby, it is possible to efficiently prevent snow from accumulating on the surface of the radome 34 on the antenna main direction side, which adversely affects the radio wave radiation characteristics.

Further, by providing a plurality of wire members 32 stretched between the rod-shaped member 28 and the peripheral edge 10a of the reflecting mirror 10, more efficient snow melting is possible.

Further, the rod-shaped member 28 may have a straight shape instead of an arc shape as shown in FIG. 1.

4 to 6 are detailed explanatory diagrams of the present invention, in which FIG. 4 is a partially cutaway side view, FIG. 5 is a perspective view of the main part, and FIG. 6 is taken along line b-b in FIG. FIG. Components that are the same as those of the embodiment described with reference to FIGS. 1 to 3 are designated by the same reference numerals, and the explanation thereof will be omitted.

In the above embodiment, the rod-shaped member 28 is used to tension the front part of the radome 34 (the part on the main direction side of the antenna).
Although the rod-like member 28 and the wire member 32 extending over the peripheral edge 10a of the reflecting mirror 10 are provided, in this embodiment, instead of these, the following structure is used.

That is, three wire members 42 extend between the vicinity of the tip of the protective frame 20 of the primary radiator 18 attached to the stay 16 that fixes and supports the -order radiator 18 and the peripheral edge 10a of the reflector 10. It is constructed by extending. Wire member 42
are made of a material such as nylon that does not affect the radio wave radiation characteristics, and are arranged approximately radially around the fixed portion on the protection frame 20 side. The wire member 42 is fixed to the peripheral edge 10a of the reflecting mirror 10 using a metal fitting 44 or the like so as to have a predetermined tension.

With this configuration, the front portion of the radome 34 is made tense, and efficient snow melting can be achieved, as in the above-mentioned embodiment.

Further, the number of the wire members 42 is not limited to three, but may be one as shown in FIGS. 7 and 8, or as shown in FIGS. 9 and 10. It is also possible to have two or more, or four or more.

=13- Furthermore, as shown in FIG.
One end of the spring member 46 may be connected to the fixed portion side of the second reflecting mirror 10, and the other end of the spring member 46 may be fixed to the rib 10b formed on the back surface of the reflecting mirror 10. With this configuration, the tension of the wire member 42 changes as appropriate due to the action of wind, etc., which causes vibrations in the radome 34, making it possible to efficiently prevent snow accretion and also making it possible to prevent excessive snow from accumulating on the wire member 42. It is also possible to prevent the occurrence of a situation that would adversely affect the -order radiator 18 when force is applied.

Note that the present invention is not limited to the above embodiments,
Other forms of parabolic antennas, Gregorian antennas,
It can also be applied to Cassegrain antennas, etc.

Effects of the Invention As described in detail above, the present invention tensions the portion of the radome on the antenna main direction side using a rod-shaped member or wire member to prevent wrinkles or loosening. Moisture from snow melting will now flow downwards without any obstruction, and warm air from the hot air generator will rise smoothly along the inner surface of the radome on the antenna main direction side, which will ensure snow accretion. This has the effect of reducing diffuse reflection of radio waves and improving radio wave radiation characteristics.

[Brief explanation of the drawing]

Fig. 1 is a partially cutaway side view of one embodiment of the present invention, Fig. 2 is a perspective view thereof, Fig. 3 is a sectional view taken along line a-a in Fig. 2, and Fig. 4 is a cross-sectional view of an embodiment of the present invention. FIG. 5 is a perspective view of the embodiment; FIG. 6 is a sectional view taken along the line b-b of FIG. 5; and FIG. 7 is a partially cutaway side view of the embodiment of the present invention. FIG. 8 is a sectional view taken along line c-c in FIG. 7; FIG. 9 is a perspective view showing a case where the embodiment of the present invention is partially modified; FIG. 10 9 is a sectional view taken along the line dd in FIG. 9, and FIG. 11 is a side view showing the main parts of a partially modified embodiment of the present invention. DESCRIPTION OF SYMBOLS 10... Reflector, 16... Stay, 18... Next radiator, 20... Protection frame, 24... Warm air generator, 28... Rod-shaped member, 32... Wire Members: 34...Radome, 42...Wire member, 46...Spring member.

Claims (1)

[Claims] 1. The primary radiator (18) of the antenna is positioned around the periphery of the reflector (10) that forms a beam in the main direction of the antenna so that the reflector (10) forms a beam in a predetermined positional relationship. Part (10a)
The radio wave radiation system of the antenna attached via the stay member (16) is wrapped in a bag-shaped radome (34), and a hot air generator (24) for generating heat convection is provided inside the radome (34). In the snow melting structure of the antenna, a rod-shaped member (28) is provided, one end of which is fixed near the tip of the stay member (16), and the other end of which is fixed near the top of the reflector (10); A snow melting structure for an antenna, characterized in that a rod-shaped member (28) tensions a portion of the radome (34) on the antenna main direction side. 2. The snow melting structure for an antenna according to claim 1, wherein the rod-shaped member (28) is formed in a straight line or an arc shape. 3. A plurality of wire members (32) are stretched across the rod-shaped member (28) and the peripheral edge (10a) of the reflecting mirror (10). Antenna snow melting structure. 4. Attach the peripheral edge (10a) of the reflector (10) so that the primary radiator (18) of the antenna is in a predetermined positional relationship with respect to the reflector (10) that forms a beam in the main direction of the antenna.
The radio wave radiation system of the antenna attached via the stay member (16) is wrapped in a bag-shaped radome (34), and a hot air generator (24) for generating heat convection is provided inside the radome (34). In the snow melting structure of the antenna, the area near the tip of the stay member (16) and the reflector (1
At least one wire member (42) is stretched between the peripheral edges (10a) of the radome (34).
A snow-melting structure for an antenna, characterized in that a portion on the main direction side of the antenna is made tense. 5. The snow melting structure for an antenna according to claim 4, wherein the wire member (42) is stretched through a spring member (46).