Abstract:
A weather-resistant radio apparatus for use at, for example, a toll booth, for transmitting data to a vehicle-mounted unit and for receiving data therefrom. The apparatus operates in a manner allowing the data transfer to occur without the need for the vehicle to stop. The data could include information for toll collection and other purposes.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to radio apparatus on the a roadside (namely, an on-road unit) that is provided in a non-stop automatic toll collection system and that is operative to transmit data, which is necessary for toll collection, to and receive such data from a vehicle-mounted unit provided on a vehicle. 
     2. Description of the Related Art 
     Generally, when a vehicle enters an expressway from an ordinary road, and, conversely, when a vehicle leaves an expressway for an ordinary road, the vehicle should temporarily stop at a tollbooth (in case where an expressway is toll road), and a driver should receive a toll ticket and pay a toll. Thus, many vehicles often queue up back from the front of the tollbooth. 
     To prevent an occurrence of a queue of vehicles (or traffic congestion) back from the front of a tollbooth, hitherto, there has been proposed a non-stop automatic toll collection system that can collect tolls without temporarily stopping vehicles at a tollbooth. 
     It is necessary for realizing such a system to perform transmission/reception of data, which is required to collect tolls, between an on-road unit, which is provided on a road, and a vehicle-mounted unit mounted on a vehicle. In this case, a transmitting antenna and a receiving antenna are attached to an on-road unit. Transmission of necessary data for toll collection is performed between an on-road unit and a vehicle-mounted unit. Thus, non-stop toll collection is performed without causing a vehicle to temporarily stop at a tollbooth. 
     The aforementioned on-road unit is, however, installed outdoors. It is, thus, necessary to prevent this on-road unit from being damaged by wind, rain, sunlight, and dust. Consequently, there has been an immediate demand that the system has protection means for protecting this on-road unit from wind, rain, sunbeams, and dust. 
     SUMMARY OF THE INVENTION 
     The present invention is accomplished in view of the aforementioned demand. Accordingly, an object of the present invention is to provide a roadside radio apparatus that can protect a radio device body and an antenna thereof from being damaged by wind, rain, sunlight, and dust, and that shows long-term durability. 
     According to an aspect of the present invention, there is provided a first roadside radio apparatus for transmitting data, which is necessary for toll collection, to a vehicle-mounted unit mounted on a vehicle and receiving the data therefrom. This roadside radio apparatus comprises a housing, a radio device body accommodated in this housing, and an antenna accommodated in the housing and connected to the radio device body. 
     With such a configuration, in which the radio device body and the antenna connected thereto are accommodated in the housing, the radio device body and the antenna can be prevented from being damaged by wind, rain, sunlight, and dust. Moreover, a roadside radio apparatus having long-term durability can be provided. 
     Further, according to a second roadside radio apparatus, which is a modification of the first roadside radio apparatus of the present invention, the housing comprises a base having a radio device body accommodating recess portion and an antenna accommodating recess portion, which are disposed back to back with each other, and using a surface part of the antenna accommodating recess portion as a radio wave reflecting surface, a base cover that covers the radio device body accommodating recess portion of this base and that constitutes a radio device body accommodating portion, which accommodates a radio device body, together with the base, and an antenna cover that covers the antenna accommodating recess portion of the base and that constitutes an antenna accommodating portion, which accommodates an antenna substrate, together with the base. 
     With such a configuration, in which the radio device body is accommodated in the radio device body accommodating portion consisting of the radio device body accommodating recess portion of the base and the base cover, and in which the antenna is accommodated in the antenna accommodating portion consisting of the antenna accommodating recess portion of the base and the antenna cover, the radio device body and the antenna can be prevented from being damaged by wind, rain, sunlight, and dust. Moreover, a roadside radio apparatus having long-term durability can be provided. 
     Additionally, electric circuit components of the radio device body can be repaired only by removing the base cover from the base. This enhances the serviceability and assemblability of the apparatus. 
     Further, according to a third roadside radio apparatus, which is a modification of the second roadside radio apparatus of the present invention, the housing further comprises a radio wave leakage preventing means for preventing radio waves, which are reflected by the radio wave reflecting surface of the base, among radio waves transmitted from the antenna from leaking toward sides of the housing. 
     With such a configuration, effects similar to those of the first roadside radio apparatus can be obtained. Moreover, among radio waves transmitted from the antenna substrate, the radio waves reflected by the radio wave reflecting portion of the base can be prevented by the radio wave leakage preventing means from leaking to the sides of the housing. Consequently, an occurrence of a phenomenon of diffraction of radio waves can be prevented. 
     Further, according to a fourth roadside radio apparatus, which is a modification of the third roadside radio apparatus of the present invention, the radio wave leakage preventing means is constituted in such a way as to block a space provided between the antenna, which is accommodated in the antenna accommodating portion, and the radio wave reflecting portion with a radio wave cutoff member for shutting off a radio wave reflected by the radio wave reflecting portion. 
     With such a configuration, effects similar to those of the first roadside radio apparatus can be obtained. Moreover, radio waves transmitted from the antenna substrate and reflected by the radio wave reflecting portion of the base are shut off by the radio wave cutoff member. Thus, the radio waves can be prevented from leaking to the sides of the housing. Consequently, an occurrence of a phenomenon of diffraction of radio waves can be prevented. 
     Further, according to a fifth roadside radio apparatus, which is an modification of the fourth roadside radio apparatus of the present invention, the radio wave cutoff member is a radio wave cutoff rib formed in the radio wave reflecting portion of the base. 
     With such a configuration, effects similar to those of the first roadside radio apparatus can be obtained. Moreover, radio waves transmitted from the antenna substrate and reflected by the radio wave reflecting portion of the base are shut off by the radio wave cutoff rib. Thus, the radio waves can be prevented from leaking to the sides of the housing. Consequently, an occurrence of a phenomenon of diffraction of radio waves can be prevented. 
     Further, according to a sixth roadside radio apparatus, which is a modification of the second roadside radio apparatus of the present invention, the antenna cover is made of a radio wave transmissive material having good weather-resistance and permittivity. 
     With such a configuration, effects similar to those of the first roadside radio apparatus can be obtained. Moreover, the antenna cover can be made of a radio wave transmissive material, for example, an ASA resin, which has good weather-resistance and permittivity. 
     Further, according to a seventh roadside radio apparatus, which is an modification of the second roadside radio apparatus of the present invention, the antenna is constituted by an antenna substrate. Moreover, the antenna accommodating portion has a distance maintaining means for maintaining the distance L between the antenna substrate and the antenna cover at a value at which characteristics of the antenna are optimum. 
     With such a configuration, effects similar to those of the first roadside radio apparatus can be obtained. Moreover, the distance L between the antenna substrate and the antenna cover can be maintained by the distance maintaining means at a value at which the antenna has optimum characteristics. Thus, variation in the characteristic, that is, axial ratio or bandwidth of this antenna can be reduced. 
     Further, according to an eighth roadside radio apparatus, which is a modification of the seventh roadside radio apparatus of the present invention, the distance maintaining means is accommodated in the antenna accommodating portion in a state in which the antenna substrate is sandwiched between one of spacers and the other spacer. Moreover, an electrically conductive cushion member is provided in the radio wave cutoff rib. Furthermore, this electrically conductive cushion member is made to abut against the antenna substrate. 
     With such a configuration, effects similar to those of the first roadside radio apparatus can be obtained. Moreover, because the distance maintaining means is accommodated in the antenna accommodating portion in a state in which the antenna substrate is sandwiched between one of the spacer and the other spacer, the strength of the antenna cover can be increased. Thus, the warpage and deformation of the antenna can be prevented. Moreover, a certain positional relationship between the antenna and the antenna cover can be maintained. 
     Furthermore, because the antenna substrate is pressed against the antenna-cover-side through the latter spacer by the radio wave cutoff rib, variation in dimensions thereof can be accommodated. Moreover, the distance L between the antenna substrate and the antenna cover can be maintained by this distance maintaining means at a value at which the antenna has optimum characteristics. Thus, variation in the characteristic, that is, axial ratio or bandwidth of this antenna can be reduced. 
     Further, according to a ninth roadside radio apparatus, which is a modification of the eighth roadside radio apparatus of the present invention, a surface portion of the antenna cover is formed like a sphere, of which radius is R, while an antenna cover facing surface portion of the other spacer is formed as a spherical portion that abuts against the surface portion of the antenna cover. 
     With such a configuration, effects similar to those of the first roadside radio apparatus can be obtained. Moreover, the strength of the antenna cover can be increased still more. 
     Furthermore, according to a tenth roadside radio apparatus, which is a modification of the ninth roadside radio apparatus of the present invention, many projections are formed on the antenna cover facing surface portion of the other spacer. 
     With such a configuration, effects similar to those of the first roadside radio apparatus can be obtained. Moreover, when the antenna cover facing surface portion is brought into contact with and pressed against the antenna cover, many projections are crushed, so that variation in dimensions thereof can be accommodated. 
     Further, according to an eleventh roadside radio apparatus, which is a modification of the second roadside radio apparatus of the present invention, the base comprises a peripheral wall portion having a base-side mating part, and further comprises a screw hole portion, which is disposed at a place that is more inward than this peripheral wall portion, and a packing receiving portion, which is disposed at a place that is more inward than this screw hole portion. Furthermore, the antenna cover comprises a peripheral wall portion having an antenna-cover-side mating portion, which is aligned with the base-side mating portion when attached to the base, and further comprises a screw seat portion disposed at a place that is more inward than this peripheral wall portion, and a packing holding portion disposed at a place that is more inward than this screw seat portion. Moreover, a waterproof packing is provided in the packing receiving portion. Furthermore, in a state in which the antenna cover is attached to the base by aligning the antenna-cover-side mating portion with the base-side mating portion and by screwing screw members, which are inserted into the screw hole portions, into the screw seat portion, the antenna accommodating portion is shut off from the outside by holding the waterproof packing by means of the packing holding portion. 
     With such a configuration, effects similar to those of the first roadside radio apparatus can be obtained. Moreover, when the antenna cover is attached to the base by aligning the antenna-cover-side mating portion with the base-side mating portion and screwing the screw members, which are inserted into the screw hole portions, into the screw seat portion, a waterproofing position, at which the packing holding portion holds the waterproof packing, is set in such a manner as to be more inward than a fixing position at which the antenna cover is fixed by the screw members. Thus, the waterproof packing performs the function of preventing water from entering the antenna accommodating portion from the screw hole portions. 
     Further, according to a twelfth roadside radio apparatus, which is a modification of the second roadside radio apparatus of the present invention, an air escape hole is provided in a surface portion of the base cover, wherein a porous waterproof sheet is provided by being stretched in this air escape hole. Moreover, a mounting seat element is fixed to a front side of the surface portion of the base cover, wherein a notch portion is provided in the mounting seat element. Furthermore, the air escape hole is placed in the notch portion. Further, amounting plate is fixed to the mounting seat element. Moreover, a space provided just above the air escape hole is closed by the mounting plate. 
     With such a configuration, effects similar to those of the first roadside radio apparatus can be obtained. Moreover, the porous waterproof sheet is provided by being stretched in the air escape hole. Furthermore, the mounting plate is placed just above the air escape hole. Thus, rainwater can be prevented from entering this air escape hole. 
     Further, according to a thirteenth roadside radio apparatus, which is a modification of the second roadside radio apparatus of the present invention, a recess portion is provided in a surface portion of the base cover. Moreover, a bottom part of the recess portion has an LED display window portion for checking whether or not an LED of the radio device body, which is accommodated in the radio device body accommodating portion. Furthermore, the LED display window is covered with a transparent panel. 
     With such a configuration, effects similar to those of the first roadside radio apparatus can be obtained. Moreover, it can be checked from this LED display window portion whether or not the LED of the radio device body is turned on. Thus, a user can judge from the outside whether or not a power supply for the radio device body is out of order. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a plan view of a roadside radio apparatus of the present invention. 
     FIG. 2 is a front view of the roadside radio apparatus. 
     FIG. 3 is a bottom view of the roadside radio apparatus. 
     FIG. 4 is a sectional view taken on line X—X of FIG.  1 . 
     FIG. 5 is an exploded perspective view of the roadside radio apparatus of the present invention. 
     FIG. 6 is a perspective view of an antenna substrate of the roadside radio apparatus. 
     FIG. 7 is a sectional view taken on line Y—Y of FIG.  6 . 
     FIG. 8 is a diagram illustrating an operation of a radio wave leakage preventing means of the roadside radio apparatus. 
     FIG. 9 is a diagram illustrating radio wave leakage. 
     FIG. 10A is a sectional view of a spacer of the roadside radio apparatus of the present invention. 
     FIG. 10B is a sectional view of another spacer of the roadside radio apparatus of the present invention 
     FIG. 11 is a schematic perspective diagram illustrating a state in which the roadside radio apparatus of the present invention is attached to a support. 
     FIG. 12 is a partially cutaway perspective exploded view of a mounting mechanism. 
     FIG. 13 is a plan view of the mounting mechanism. 
     FIG. 14 is a front view of the mounting mechanism. 
     FIG. 15 is a side view of the mounting mechanism. 
     FIG. 16 is a front view of a lateral-member mounting member in the mounting mechanism. 
     FIG. 17 is a side view of a lateral-member mounting member in the mounting mechanism. 
     FIG. 18 is a bottom view of a lateral-member mounting member in the mounting mechanism. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. 
     FIG. 1 is a plan view of a roadside radio apparatus of the present invention. FIG. 2 is a front view of the roadside radio apparatus. FIG. 3 is a bottom view of the roadside radio apparatus. FIG. 4 is a sectional view taken on line X—X of FIG.  1 . FIG. 5 is an exploded perspective view of the roadside radio apparatus of the present invention. 
     As illustrated in FIGS. 1 to  5 , the roadside radio apparatus A of the present invention has a housing  70 , a radio device body U accommodated in the housing  70 , and an antenna substrate (or antenna)  30  accommodated in the housing  70  and connected to the radio device body U. The housing  70  has an aluminum die-cast integral-type base  1 , a base cover  11 , which covers an upper part of this base  1 , and an antenna cover  25  that is attached to a lower portion of the base  1  and made of an ASA resin. 
     As shown in FIGS. 4 and 5, the base  1  has a base body  1 A of a square horizontal section. A square-frame-like peripheral wall portion  2  is formed on one of surface portions (namely, the top surface portion)  1   a  of this base body  1 A. A space surrounded by this peripheral wall portion  2  serves as a radio device body accommodating recess portion  3 A. A mating part  2 A is formed on an end surface part  2   a  of the peripheral wall portion  2 . Further, a rib-like packing holding portion  4 A is formed over the entire periphery of the mating part  2 A. Further, a plurality of screw holes  4 B are provided in the mating part  2 A of the peripheral wall portion  2  and serve as lid mounting parts. Moreover, a part of one of the surface portions la is established in such a way as to be outer than the peripheral wall portion  2  and serve as a cover attaching part  5 . A plurality of screw hole parts  5 A are provided in this cover attaching portion  5 . 
     Furthermore, as illustrated in FIG. 4, a peripheral wall portion  6  is formed on the other surface portion (namely, the bottom surface portion)  1   b  of the base body  1 A. A space surrounded by this peripheral wall portion  6  serves as an antenna accommodating recess portion  71 . A peripheral edge part of this peripheral wall portion  6  serves as a base-side mating part  7 . Further, a packing receiving portion  8  is formed on the other surface portion  1   b  of the base body  1 A in such a manner as to be placed more inward than and nearly parallel with the peripheral wall portion  6 . Moreover, a radio wave cutoff rib  9  is formed on the surface portion  1   b  of the base body  1 A in such a manner as to be placed more inward than the packing receiving portion  8  and nearly parallel with the peripheral wall portion  6 . Further, a packing fitting groove portion  8   b  is formed in an end surface part  8   a  of the packing receiving portion  8 . A waterproof packing  10  is fitted into the packing fitting groove portion  8   b.    
     As illustrated in FIGS. 4 and 5, the base cover  11  has a cover body  11 A of a square horizontal section. A square-frame-like peripheral wall portion  12  is formed on this cover body  11 A. A mating portion  22  is formed on an end surface part  12   a  of the peripheral wall portion  12 . A packing fitting groove portion  22 A is formed in the mating portion  22 . Waterproof packing  22 B is fitted into this packing fitting groove portion  22 A. Further, a mounting portion  13  having screw inserting hole parts  13   a  is formed on the peripheral edge part of the peripheral wall portion  12 . Moreover, a rectangular recess portion  14  is formed in a surface portion  11   a  of the cover body  11 A by being placed on a side thereof. An LED display window portion  15  is provided in the bottom portion of this recess portion  14 . This LED display window portion  15  is covered with a transparent panel  16 . 
     Further, an air escape hole  17  is provided at a side opposite to the LED display window portion  15  formed in the surface portion  11   a  of the cover body  11 A. A porous waterproof sheet  18  is mounted in this air escape hole  17  with a mounting member  18 A. A mounting seat element  19  is fixed to the front side of the surface portion  11   a  of the cover body  11 A. A U-shaped notch portion  20  and screw portions  21  provided on both sides of this notch portion  20  are formed in this mounting seat element  19 . The air escape hole  17  is positioned in the notch portion  20 . 
     Moreover, a mounting plate  23  is put on and fixed to this mounting seat element  19  by screw members  24 . The notch portion  20  is covered with this mounting plate  23 . A space provided just above the air escape hole  17  is closed by the mounting plate  23 . Furthermore, both end portions (namely, left and right end portions) of the mounting plate  23  project outwardly from both end portions (namely, left and right end portions)  19 A and  19 B of the mounting seat element  19 , respectively. These end portions serving as projection portions constitute engaging portions  23 A and  23 B, respectively. 
     Further, the base cover  11  covers the radio device body accommodating recess portion  3 A of the base  1  and thus constitutes the radio device body accommodating portion  3 , which accommodates the radio device body U, together with this base  1 . This radio device body accommodating portion  3  contains the radio device body U. 
     That is, in a state in which the radio device body U is accommodated in the radio device body accommodating recess portion  3 A, the base cover  11  is provided along an upper portion of the base  1  by aligning the mating portion  2 A of this base  1  with the mating portion  22 . The base cover  11  is attached to the base  1  by screwing attaching screw members  39 , which are inserted into the screw inserting hole parts  13   a  of the mounting portion  13 , into screw holes  4 B of the cover attaching portion  5 A. In this case, the packing holding portion  4 A performs a sealing function by being pressed against the waterproof packing  22 B provided in the packing fitting groove portion  22 A. 
     As shown in FIGS. 4 and 5, the antenna cover  25  is made of an ASA resin that is a radio wave transmissive material having high weather-resistance and permittivity. A peripheral wall portion  26  is formed on a peripheral portion of the cover body  25 A. The peripheral edge portion of this peripheral wall portion  26  serves as an antenna-cover-side mating portion  27 . Further, a rib-like packing holding portion  28  is formed on the inner surface of the cover body  25  in such a way as to be more inward than the peripheral wall portion  26  and nearly parallel thereto. This packing holding portion  28  is connected to the peripheral wall portion  26  through a plurality of connecting ribs  28 F. 
     Furthermore, a plurality of antenna substrate receiving portions  27 F are formed on an inner surface portion  25   a  of the cover body  25  in such a way as to be more inward than the packing holding portion  28 . Further, a plurality of screw seat portions  29  are formed on the inner surface portion  25   a  of the cover body  25 A in such a manner as to be outer than the packing holding portion  28  and more inward than the peripheral wall portion  26 . A screw hole  29 A is formed in each of the screw seat portions  29 . Moreover, as shown in FIG. 10A, the inner surface portion  25   a  of the cover body  25 A is shaped like a sphere of a radius R. 
     Furthermore, the antenna cover  25  covers the antenna accommodating recess portion  71  of the base  1  and thus constitutes the antenna accommodating portion  80 , which accommodates the antenna substrate  30 , together with this base  1 . 
     Further, as shown in FIG. 6, the antenna substrate  30  has a substrate body  30 A. Patterns (namely, peripheral through hole patterns)  31  and  32  are provided around the front surface (or bottom surface)  30   a  and the rear surface (or top surface)  30   b  of this substrate body  30 A, respectively. Many through holes  33  are provided in these patterns  31  and  32 . The patterns  31  and  32  are connected to each other through these through holes  33 . 
     Furthermore, as shown in FIGS. 4 and 5, one of spacers  35  (namely, an upper spacer) is made of a foaming material and shaped in such away as to cover the back-surface side  30   b  (namely, the top-surface side) of the antenna substrate  30 . 
     Further, as shown in FIGS. 4 and 5, the other spacer  36  (namely, a lower spacer) is made of a foaming material and shaped in such a way as to cover the front-surface side  30   a  (namely, the bottom-surface side) of the antenna substrate  30 . That is, as shown in FIG. 10A, in the other (or lower) spacer  36 , the former surface portion (namely, the top surface portion)  36   a  is formed as a flat surface that abuts against the surface  30   a  of the antenna substrate  30 . The other surface portion (or bottom surface portion)  36   b  serving as an antenna cover facing portion is shaped like a sphere of a radius R in such a way as to abut against the spherical inner surface portion  25   a  of a radius R. 
     Furthermore, in the antenna cover  25 , the former and latter spacers  35  and  36  and the antenna substrate  30  are accommodated in a state in which the antenna substrate  30  are sandwiched between the former spacer  35  and the latter spacer  36 . The surface portion  36   b  of the latter spacer  36  abuts against the spherical inner surface portion  25   a  of a radius R of the antenna cover  25 . 
     Further, in a state in which an electrically conductive cushion rubber  37  of a U-shaped section is attached to the radio wave cutoff rib  9  of the base  1 , the antenna cover  25  is provided along the base  1  by aligning an antenna-cover-side mating portion  27  with the base-side mating portion  7  of this base  1 . The antenna cover  25  is attached to the base  1  by screwing attaching screw members  38 , which are inserted into the screw inserting holes  5   a  of the cover attaching portion  5 A of the base body  1 A, into screw holes  29 A of the screw seat portion  29  of the antenna cover  25 . 
     In this case, the rib-like packing holding portion  28  of the antenna cover  25  performs a sealing function by touching the waterproof packing  10  provided in the packing fitting groove portion  8   b  of the base  1 . Further, the radio wave cutoff rib  9  of the base  1  is placed outside the peripheral edge portion of the former spacer  35 . The electrically conductive cushion rubber  37  attached to this radio wave cutoff rib  9  is in contact with the pattern  32  of the peripheral portion of the rear surface  30   b  of the antenna substrate  30 . 
     Thus, in the antenna accommodating portion  80 , the former spacer  35  and the latter spacer  36  are accommodated in a state in which the substrate  30  is sandwiched between the spacers  35  and  36 . Further, the electrically conductive cushion member  37  is provided in the radio wave cutoff rib  9 . Moreover, this electrically conductive cushion member  37  is made to abut against the antenna substrate  30 . Consequently, the grounding terminal of the antenna substrate  30  can be brought into contact with the base  1  in a stable condition. Furthermore, the distance between the antenna substrate  30  and the antenna cover  25  can be maintained at a value at which the antenna has optimum characteristics. 
     Further, in the antenna accommodating portion  80 , the former spacer  35  and the latter spacer  36  are accommodated in a state in which the substrate  30  is sandwiched between the spacers  35  and  36 . Furthermore, the electrically conductive cushion member  37  is provided in the radio wave cutoff rib  9 . Moreover, this electrically conductive cushion member  37  is made to abut against the antenna substrate  30 . Thus, a distance maintaining means is constituted. 
     The distance L between the antenna substrate  30  and the antenna cover  25  can be maintained by this distance maintaining means at a value at which the antenna has optimum characteristics. Thus, variation in the characteristic, that is, axial ratio or bandwidth of this antenna can be reduced. 
     Further, the inner surface portion  25   a  of the antenna cover  25  is shaped like a sphere of a radius R. The latter surface portion  36   b  serving as an antenna cover facing surface portion of the latter spacer  36  is shaped like a sphere. The latter surface portion  36   b  is made to abut against the inner surface portion  25   a  of the antenna cover  25 . Consequently, the strength of this antenna cover  25  can be increased. 
     Furthermore, as illustrated in FIG. 10B, many projections  36 A are formed on the latter surface portion  36   b  of the latter spacer  36 . Thus, when the latter surface portion  36   b  is brought into contact with and pressed against the inner surface portion  25   a  of the antenna cover  25 , the projections  36 A are crushed, so that variation in dimensions thereof can be accommodated. 
     Further, the latter surface portion (or bottom surface portion)  1   b  of the base body  1 A serves as a radio wave reflecting surface (or radio wave reflecting portion) S. Moreover, the rear-surface side  30   b  of the antenna substrate  30  is surrounded by the radio wave cutoff ribs  9 . 
     That is, the housing  70  has a radio wave leakage preventing means for preventing radio waves W, which are reflected by the radio wave reflecting surface S of the base  1 , among radio waves transmitted from the antenna substrate  30  from leaking toward the sides of the housing  70 . 
     This radio wave leakage preventing means is constituted by shutting off a space provided between the antenna substrate  30 , which is accommodated in the antenna accommodating portion  80 , and the radio wave reflecting surface S from the outside with the radio wave cutoff ribs  9  serving as radio wave cutoff members for cutting off the radio waves W reflected by this radio wave reflecting surface S. 
     Owing to the presence of this radio wave leakage preventing means, the radio waves W transmitted from the antenna substrate  30  and reflected by this radio wave reflecting surface S are shut off by the radio wave cutoff ribs  9 , as shown in FIG.  8 . Thus, the radio waves W can be prevented from leaking to the sides of the housing  70 . Consequently, an occurrence of a phenomenon of diffraction of radio waves can be prevented. 
     When there is no radio wave leakage preventing means, the radio waves W transmitted from the antenna substrate  30  and reflected by this radio wave reflecting surface S are not shut off. Thus, the radio waves leak toward the sides of the housing  70 . Consequently, the phenomenon of diffraction of the radio waves is caused. 
     As described above, the radio device body U and the antenna substrate  30  connected to this radio device body U are accommodated in the housing  70 . That is, the radio device body U is accommodated in the radio device accommodating portion  3  constituted by the radio device body accommodating recess portion  3 A of the base  1  and the base cover  1 . Moreover, the antenna substrate  30  is accommodated in the antenna accommodating portion  80  constituted by the antenna accommodating recess portion  71  of the base  1  and the antenna cover  25 . Thus, the radio device body U and the antenna substrate  30  can be prevented from being damaged by wind, rain, sunlight, and dust. Consequently, the present invention can provide a roadside radio apparatus having long-term durability. 
     Moreover, electric circuit components of the radio device body U can be repaired only by removing the base cover  11  from the base  1 . This enhances the serviceability and assemblability of the apparatus. 
     Further, when the antenna cover  25  is attached to the base  1  by aligning the antenna-cover-side mating portion  27  with the base-side mating portion  7  and screwing the screw members  38 , which are inserted into the screw hole portions  5 A, into the screw seat portion  29 , a waterproofing position P 1 , at which the packing holding portion  28  holds the waterproof packing  10 , is set in such a manner as to be more inward than a fixing position P 2  at which the antenna cover  25  is fixed by the screw members  38 . Thus, the waterproof packing  10  performs the function of preventing water from entering the antenna accommodating portion  80  from the screw hole portions  5 A. 
     Moreover, the air escape hole  17  is provided in the surface portion  11 A of the base cover  11 . The porous waterproof sheet  18  is provided by being stretched in this air escape hole  17  by means of a mounting member  18 A. The mounting seat element  19  is fixed to the front side of the surface portion  11 A of the base cover  11 . The notch portion  20  is provided in this mounting seat element  19 . The air escape hole  17  is placed in the notch portion  20 . The mounting plate  23  is fixed to this mounting seat element  19 . The space provided just above the air escape hole  17  is closed by the mounting plate  23 . Thus, rainwater can be prevented from entering this air escape hole  17 . 
     Furthermore, the recess portion  14  is provided in the surface part of the surface portion  11 A of the base cover  11 . The bottom part of this recess portion  14  has the LED display window portion  15  for checking whether or not an LED  81  provided on the printed circuit board  82  of the radio device body U, which is accommodated in the radio device body accommodating portion  3 A, is turned on. This LED display window portion  15  is covered with the transparent panel  16 . This enables a user to check from this LED display window portion  15  whether or not the LED of the radio device body U is turned on. Thus, a user can judge from the outside whether or not a power supply for the radio device body U is out of order. 
     The roadside radio apparatus A constructed as described above is attached to, for example, a lateral member D of a support C by a mounting mechanism (or a fitting) , as illustrated in FIG.  11 . This mounting mechanism B is connected to the base cover  11  of the antenna apparatus A. 
     That is, as illustrated in FIGS. 12 to  18 , the mounting mechanism B comprises a mounting plate  23  fixed onto the mounting seat element  19 , an insert-mounting member  40 , an angular adjusting member  41 , and a lateral-member mounting member  42 . 
     The insert-mounting member  40  has a holding portion  43  of a U-shaped section. Mounting plate portions  44 A and  44 B are formed on both side edge portions of this holding portion  43 . Further, a hole portion  45  for a fulcrum, and a fixing hole portion  46  are formed in a side surface portion  43   a  of the holding portion  43 . Moreover, inserting portions  47  and  48 , which project backwardly, are formed on the left and right rear edge portions of the mounting plate portions  44 A and  44 B, respectively. Furthermore, the mounting hole portion  40 A is provided in each of the mounting plates  44 A and  44 B. 
     Furthermore, the angular adjusting member  41  has a surface portion  49  and side surface portions  50  and  51  each bent perpendicular to this surface portion  49 , and also has a U-shaped section. As shown in FIG. 13, a pair of elongated arcuate hole portions  52  each extending along a part of a circle, whose center is located at a point P, are provided in the surface portion  49  in such a manner as to be opposed to each other. Moreover, a hole portion for a fulcrum  53 , and an arcuate elongated hole portion  54 , which extends along apart of a circle, whose center is located at this hole portion  53 , are provided in each of side surface portions  50  and  51 . 
     Further, the hole portions  45  and  53  for a fulcrum are aligned with each other by putting the angle adjusting member  41  on the holding portion  43  of the insert-mounting member  40 . Then, a bolt  55  serving as a member for a fulcrum is inserted into these hole portions  45  and  53 . Thus, a nut  56  is screwed into this bolt  55 . Moreover, a bolt  57  serving as a locking member is inserted into the fixing hole portion  46  from the elongated hole portion  54 . Then, a nut  58  is screwed into this bolt  57 . Thus, the angle adjusting member  41  is attached to the insert-mounting member  40 . 
     Furthermore, the lateral-member mounting member  42  comprises a U-shaped bolt  59 , a clamping member  60 , and a holding member  61 . The clamping member  60  has inserting holes  62  provided in both side portions thereof. Further, the holding member  61  has a holding portion  63  of a U-shaped section. Mounting portions  64 A and  64 B each having an inserting hole  66  are formed in both side edge parts of this holding portion  63 . A surface part  63   a  of the holding portion  63  has a pair of bolt inserting hole portions  65 . 
     Furthermore, the antenna apparatus A is attached to the lateral member D of the support C by the aforementioned mounting mechanism B. That is, the U-shaped bolt  59  is engaged with the lateral member D. Then, the clamping member  60  and the holding member  61  are attached to this U-shaped bolt  59  by using the inserting holes  62  and  66 . The holding member  61  is fixed to the lateral member D through the clamping member  60  and the U-shaped bolt  59  by tightening the nut member  67  screwed into the U-shaped bolt  59 . 
     Then, bolts  68  are inserted into the bolt inserting hole portions  65  of the surface portion  63 a of the holding member  61 . Further, these bolts  68  are inserted into the arcuate elongated hole portions  52  of the angular adjusting member  41 . Then, the nut members  69  are screwed. Furthermore, the insert-mounting member  40  and the angle adjusting member  41  are held by the holding member  61 . 
     Subsequently, the roadside radio apparatus A is lifted. Then, the inserting portions  47  and  48  of the insert-mounting member  40  are inserted under and engaged with the engaging portions  23 A and  23 B provided at both end portions of the mounting plate  23 , which is put on and fixed to the mounting seat element  19  of the base cover  11 . Thus, the mounting plate portions  44 A and  44 B are fixed to the base cover  11  by means of mounting bolts  70  by using the mounting hole portions  40   a.    
     As described above, according to the roadside radio apparatus of the present invention, the radio device body and the antenna connected to this radio device body are accommodated in the housing. Thus, the radio device body and the antenna can be prevented from being damaged by wind, rain, sunlight, and dust. Consequently, the present invention can provide a roadside radio apparatus having high long-term durability. 
     Further, according to the roadside radio apparatus of the present invention, the radio device body is accommodated in the radio device body accommodating portion consisting of the radio device body accommodating recess portion of the base and the base cover. Moreover, the antenna is accommodated in the antenna accommodating portion consisting of the antenna accommodating recess portion of the base and the antenna cover. Thus, the radio device body and the antenna can be prevented from being damaged by wind, rain, sunlight, and dust. Furthermore, a roadside radio apparatus having long-term durability can be provided. Additionally, electric circuit components of the radio device body can be repaired only by removing the base cover from the base. This enhances the serviceability and assemblability of the apparatus. 
     Moreover, according to the roadside radio apparatus of the present invention, among radio waves transmitted from the antenna substrate, the radio waves reflected by the radio wave reflecting portion of the base can be prevented by the radio wave leakage preventing means from leaking to the sides of the housing. Consequently, an occurrence of a phenomenon of diffraction of radio waves can be prevented. 
     Further, the radio wave leakage preventing means is constituted in such a way as to block a space provided between the antenna, which is accommodated in the antenna accommodating portion, and the radio wave reflecting portion with a radio wave cutoff member (for instance, a radio wave cutoff rib formed in the radio wave reflecting portion of the base) for shutting off a radio wave, which is reflected by the radio wave reflecting portion, from the outside. 
     Moreover, according to the roadside radio apparatus of the present invention, the antenna cover can be made of a radio wave transmissive material, for example, an ASA resin, which has good weatherability and permittivity. 
     Moreover, according to the roadside radio apparatus of the present invention, the distance L between the antenna substrate and the antenna cover can be maintained by the distance maintaining means at a value at which the antenna has optimum characteristics. Thus, variation in the characteristic, that is, axial ratio or bandwidth of this antenna can be reduced. 
     Moreover, according to the roadside radio apparatus of the present invention, the distance maintaining means can be accommodated in the antenna accommodating portion in a state in which the antenna substrate is sandwiched between one of the spacer and the other spacer. Thus, the strength of the antenna cover can be increased. Consequently, the warpage and deformation of the antenna can be prevented. Moreover, a certain positional relationship between the antenna and the antenna cover can be maintained. 
     Furthermore, because the antenna substrate is pressed against the antenna-cover-side through the latter spacer by the radio wave cutoff rib, variation in dimensions thereof can be accommodated. Moreover, the distance L between the antenna substrate and the antenna cover can be maintained by this distance maintaining means at a value at which the antenna has optimum characteristics. Thus, variation in the characteristic, that is, axial ratio or bandwidth of this antenna can be reduced. 
     Further, according to the roadside radio apparatus of the present invention, a surface portion of the antenna cover is formed like a sphere, while an antenna cover facing surface portion of the other spacer is formed as a spherical portion that abuts against the surface portion of the antenna cover. Thus, the strength of the antenna cover can be increased still more. Moreover, many projections are formed on the antenna cover facing surface portion of the other spacer. Thus, when the antenna cover facing surface portion is brought into contact with and pressed against the antenna cover, many projections are crushed, so that variation in dimensions thereof can be accommodated. 
     Moreover, according to the roadside radio apparatus, when the antenna cover is attached to the base by aligning the antenna-cover-side mating portion with the base-side mating portion and screwing the screw members, which are inserted into the screw hole portions, into the screw seat portion, a waterproofing position, at which the packing holding portion holds the waterproof packing, is set in such a manner as to be more inward than a fixing position at which the antenna cover is fixed by the screw members. Thus, the waterproof packing performs the function of preventing water from entering the antenna accommodating portion from the screw hole portions. 
     Moreover, according to the roadside radio apparatus of the present invention, the air escape hole is provided in the surface portion of the base cover. The porous waterproof sheet is provided by being stretched in this air escape hole. The mounting seat element is fixed to the front side of the surface portion of the base cover. The notch portion is provided in this mounting seat element. The air escape hole is provided in the notch portion. The mounting plate is put on and fixed to this mounting seat element. The space provided just above the air escape hole is closed by the mounting plate. Thus, rainwater can be prevented from entering this air escape hole. 
     Moreover, according to the roadside radio apparatus of the present invention, a recess portion is provided in the surface portion of the base cover. Furthermore, a bottom part of this recess portion has an LED display window portion for checking whether or not an LED of the radio device body, which is accommodated in the radio device body accommodating portion. Furthermore, this LED display window is covered with a transparent panel. Thus, it can be checked from this LED display window portion whether or not the LED of the radio device body is turned on. Consequently, a user can judge from the outside whether or not a power supply for the radio device body is out of order. 
     While only a certain embodiment of the invention has been specifically described herein, it will be apparent that numerous modifications may be made thereto without departing from the spirit and scope of the invention. 
     The present invention is based on Japanese Patent Application No. Hei. 11-210828 which is incorporated herein by reference.