Adjustable antenna mount for parabolic antennas

An antenna mount for aiming a parabolic antenna towards a geosynchronous satellite characterized by four, pivotal sub-assemblies, each of which is rotatable around its own axis. The mount can be quickly adjusted to point the antenna at a particular geosynchronous satellite, or may be caused to sweep across the satellite belt in a scanning manner. The antenna mount can be attached to a support post of virtually any orientation ranging from vertical to horizontal.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
This invention relates generally to antenna mounts, and more particularly 
to mounts for aiming a parabolic antenna towards communication satellites 
in geosynchronous orbit. 
2. Description of the Prior Art 
There are a great number of communication satellites parked in 
geosynchronous orbit 22,300 miles above the equator of the earth. Highly 
directional parabolic antennas are used to receive the signals transmitted 
from these geosynchronous satellites. 
To receive an adequate signal, the parabolic antenna must be accurately 
aimed at a geosynchronous satellite. To accomplish this task, a number of 
designs for adjustable antenna mounts have been devised. 
Since all of the geosynchronous satellites lie along a plane through the 
earth's equator, any parabolic antenna in the Northern hemisphere should 
be pointed south. The angle of elevation of the antenna depends upon the 
latitude at which it is being used, where the angle of elevation decreases 
with increasing latitude. The antenna should also be able to sweep along 
the satellite belt so that it may be aimed at the desired geosynchronous 
satellite. 
A great many antenna mounts have been devised which are used to aim a 
parabolic antenna towards a geosynchronous satellite. Most fall into two 
main categories. A first category of antenna mount utilizes a number of 
legs to support the antenna, where two or more of the legs are adjustable 
to provide the proper elevation of the antenna and to align the axis 
rotation of the antenna with a vertical plane. 
A problem with this type of antenna mount is that it is very difficult to 
set the mounts accurately, and any error in setting the mount will make 
proper tracking with the antenna impossible. The difficulty of setting up 
the first type of mount is compounded by the fact that adjustment of one 
of the legs will often cause the other adjustable leg(s) to become 
unadjusted. 
The other major type of antenna mount utilizes a single support pole having 
a head which permits rotation for North/South orientation, and for the 
proper elevation. If, however, the post is not set exactly vertical, 
tracking becomes once again impossible. 
Examples of tripodal mounts for parabolic dishes can be found in U.S. Pat. 
No. 3,945,015 of Guegeun, and U.S. Pat. No. 4,086,599 of VanderLinden, Jr. 
et al. The Gueouen patent describes a support structure for an antenna 
mounted at three points on a steering mounting resting on the ground. One 
of the points is situated at the apex of the support frame and is provided 
with a bi-directional joint which allows the antenna to pivot around an 
azimuthal and elevational axes. The bi-directional joint is mounted to 
pivot on the base mounting around an axis which is perpendicular to the 
azimuthal and elevational axes. The VanderLinden, Jr. et al. patent 
describes a composite antenna which is secured to a foundation by a 
multi-element truss-like pedestal. The pedestal provides elevation and 
azimuth rotational axes for selecting and adjusting the reflector point 
orientation. 
SUMMARY OF THE INVENTION 
An object of this invention is to provide a simple, easy to use antenna 
mount for directional antennas. 
Another object of this invention is to provide an antenna mount which may 
be quickly readjusted to point the antenna towards a satellite in 
geosynchronous orbit. 
Briefly, the antenna mount includes a base assembly rotatable around a 
first axis, an elevation adjustment assembly coupled to the base assembly 
and rotatable around a second axis, a vertical orientation adjustment 
assembly coupled to the elevation adjustment assembly and rotatable around 
a third axis, and a tracking adjustment assembly coupled to the vertical 
orientation adjustment assembly and rotatable around a fourth axis. The 
base assembly is attached to a tripod or support post, and the parabolic 
antenna is attached to the tracking adjustment assembly. The antenna is 
also coupled to the vertical orientation adjustment assembly by a sweep 
assembly which allows the antenna to be pointed at various locations along 
the satellite belt. 
An advantage of this invention is that it can be rotated in three planes, 
making the antenna easy to set up, adjust, and readjust should the 
necessity arise due to the shifting of the mounting base. 
Another advantage to this invention is that it can be quickly and easily 
adjusted by one person, as opposed to prior art mounts which often took a 
team of technicians to adjust. 
In another advantage to this invention is that the antenna mount can be 
attached to a pole or tripod which is not vertical. This permits the 
antenna to be mounted on sloping surfaces, such as a roof, or even on a 
horizontal pole mounted on the side of a building. 
Yet another advantage of this invention is that the antenna can be quickly 
and easily readjusted should the mounting pole or tripod shift due to 
frost heave or due to improper or insecure installation. 
A still further advantage of this invention is that the sweep assembly, 
since it is attached to the vertical orientation adjustment assembly, 
rotates with the antenna. This eliminates the requirement for swivel or 
ball joints which were needed with prior art mounts because of the 
twisting action as the antenna sweeps across the satellite belt. 
These and other objects and advantages of the present invention will no 
doubt become apparent upon a reading of the following descriptions and a 
study of the several figures of the drawing.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT(S) 
Referring to FIG. 1, an adjustable antenna mount 10 in accordance with the 
present invention is shown attached to a tripod 12 and a directional, 
parabolic antenna 14. The tripod 12 includes three legs 16 and a post 18 
to which the legs are attached. Antenna 14 includes a parabolic dish 20, a 
mounting frame 22 attached to the underside of dish 20, a receiving 
element 24, and a number of struts 26 supporting the receiving element. 
Referring now to FIGS. 1 and 2, the mount of the present invention includes 
a base assembly 28, an elevation adjustment assembly 30, a vertical 
orientation adjustment assembly 32, and a tracking adjustment assembly 34. 
A sweep assembly 36 is coupled between vertical orientation adjustment 
assembly 32 and frame 22 of antenna 14. 
Referring now to FIGS. 2, 4, and 5, base assembly 28 includes a base sleeve 
38 which telescopes over the end of post 18. Alternately, sleeve 38 could 
telescope within post 18. Base sleeve 38 is provided with a pair of 
locking bolts 40 for selectively affixing base sleeve 38 to the post 18 
within. Attached to and part of base assembly 28 is a cylindrical base 
bearing 42 which supports the elevation adjustment assembly 30. 
Elevation adjustment assembly 30 includes a pair of base bearing engagement 
members 44 which are disposed within base bearing 42. A pair of frame 
members 46 are attached, preferably by welding, to the engagement members 
44, and are, in turn, attached to a vertical orientation adjustment 
bearing 48. A pair of locking bolts 50 lock the vertical orientation 
assembly in position. The elevation adjustment assembly 30 is pivotally 
supported by bearing engagement member 44 and locked by a nut and bolt 
assembly 43. 
An elevation adjustment bolt 51 extends between a clevis 53 and a flange 
55. A nut 57 is en9aqed with an end of bolt 51 such that tightening nut 57 
causes the elevation adjustment assembly to pivot around an axis A2 (see 
FIG. 4). 
Referring now more particularly to FIG. 7, but also additionally to FIGS. 2 
and 3, vertical orientation adjustment assembly 32 includes a bearing 
engagement member 52 which engages vertical orientation adjustment bearing 
48, a sweep assembly support bar 54 attached to one end of bearing 
engagement member 52, and a tracking orientation bearing member 56 
attached to the other end of bearing engagement member 52. 
Tracking adjustment assembly 34 includes a bearing engagement member 58 
which is disposed within tracking orientation bearing member 56. Attached 
to the upper end of tracking adjustment assembly 34 is the first flange 
member 60, and attached to the bottom of bearing engagement member 58 is a 
second flange member 62. 
A pair of coarse adjustment straps 64 are attached at one end to frame 22 
of antenna 14, and are provided with a number of spaced apart holes 66. A 
nut and bolt assembly 68 is inserted through a pair of holes in coarse 
adjustment strap 64 and engages a hole provided within first flange member 
60. 
An adjustment bolt 70 is attached at one end to frame 22, and engages a 
hole provided in second flange member 62. A pair of nuts 72 affixed a 
midlength portion of adjustment bolt 70 to the second flange member 62. 
Referring now to FIGS. 1 and 6, sweep assembly 36 includes a screwjack 74 
having an outer sleeve 76, an inner sleeve 78, an elongated drive screw 80 
rotatably coupled to an end of outer sleeve 76, and a nut 82 coaxially 
attached with an inner sleeve 78 and engaging drive screw 80. A handle 84 
is provided for rotating drive screw 80. 
Outer sleeve 76 is coupled to the sweep assembly support bar 54 of vertical 
orientation adjustment assembly 32 by a connector 88. Inner sleeve 78 is 
coupled to frame 22 of antenna 14 by a clevis 90. 
In operation, the tripod 12 is set up such that post 18 is as vertical as 
possible. Alternatively, post 18 can be set into the ground with concrete. 
Base sleeve 38 is engaged with post 18 and frame 22 of antenna 14 is 
attached to flanges 60 and 62 of the tracking adjustment assembly. 
Antenna 14 is pointed in a due south direction by rotating the base 
assembly 28 around a first axis A1. When the antenna 14 is pointed due 
south, locking bolts 40 are used to firmly lock base sleeve 38 to post 18. 
To obtain the proper elevation for antenna 14, nut 57 is loosened or 
tightened on elevation adjustment bolt 51 to cause the elevation 
adjustment assembly 30 to rotate around a second axis A2 (see FIG. 4) 
until the antenna is at approximately the correct elevation. Frame members 
46 are then clamped to base bearing 42 by tightening nut and bolt assembly 
43 to firmly lock it in position. 
The vertical orientation of the antenna is adjusted by rotating the 
vertical orientation assembly around a third axis A3. Once the proper 
vertical orientation has been obtained, the vertical orientation assembly 
32 is clamped to the elevation adjustment bearing 48 by locking bolts 50. 
The offset of the antenna is coarsely adjusted by engaging nut and bolt 
assembly 68 with one of the three holes 66. The fine offset adjustment for 
the antenna is obtained by adjusting the attachment point of flange 62 to 
adjustment bolt 70. The offset of the antenna sweep axis A4 is determined 
by latitude and must be set accurately for a particular location. 
The antenna 14 is swept along the satellite belt by rotating crank 84 of 
screwjack 74. Once the parabolic antenna 14 is focused the desired 
satellite, the adjustment of the antenna is complete. 
It should be noted that the antenna mount 10 of the present invention does 
not require post 18 to be vertical, or even any where near vertical. If 
the orientation of post 18 shifts due, for example, to frost heave, the 
antenna mount can be readjusted as previously described to quickly aim the 
antenna 22 to the proper satellite. 
While this invention has been described in terms of a few preferred 
embodiments, it is contemplated that persons reading the preceding 
descriptions and studying the drawing will realize various alterations, 
permutations and modifications thereof. For example, while the present 
invention is concerned with receiving information from apparently 
stationary satellites in geosynchronous orbit, with minor modifications it 
could be adapted to track satellites which are not in geosynchronous 
orbit. By providing suitably calibrated drive motors, the antenna could be 
caused to automatically move around its first, second, and third axes to 
continuously track a satellite as it moves from horizon to horizon. 
It is therefore intended that the following appended claims be interpreted 
as including all such alterations, permutations and modifications as fall 
within the true spirit and scope of the present invention.