TVRO System Angles

Setup Satellite Good Info. (like to Satellite Help)

To set up a big dish you need to first have a line of sight (LOS) for your dish to travel on an arc to view communication satellites. If you have buildings or trees in the view of the sky you won't be able to receive those satellites signals.

Second you need to have a level pole installed, either on a roof top or in the ground. If you choose a ground installation you must install the pole below the frost line (what ever the building code is for your specific area) and have it set in concrete. Its best to have a piece of angle iron or rebar welded to part of the pole that will be installed in the cement, as this will minimize the pole from wanting to twist in the ground.

Third you need to have set the dishes mount to point in the true south position, and to set the declination and polar axis. Then connect all the wires to lnb's, servo motor & actuator. Then connect all this to the receiver inside. Note its best to run these cables in conduit (plastic piping) and have this buried in the ground. This protects the cables and helps prolong there life.


To calculate where a fixed dish will point from your latitude and longitude and satellites west longitude position, this calculation below will give you the exact azimuth and elevation for your fixed dish.

This calculation is also good for checking your line of sight (LOS) for a big dish installation. You would calculate 137.0°W satellite AMC 7, 97.0°W satellite Telstar 5 & 58.0°W satellite PAS 9 to give you three compus points. Use these three points to form an arc with satellite T5 in the middle. This is the LOS that you need for your big dish to receive most of all the North American satellites.

Your Site's North Latitude: degrees
Your Site's West Longitude: degrees
Satellite's West Longitude: degrees
Azimuth (Compass): degrees
Elevation: degrees

Formula where: L= latitude in degrees West, S= satellite position in degrees west & n= longitude in degrees west

Note: itan= invers tan or tan to the minus power one & icos=invers cos or cos to the minus power of one

Elevation = itan ((cos (icos (L * cos(S-n))) - 0.15116) / sin(icos (cos L * cos(S-n))))

Azimuth = icos (( -tan L / tan (icos (cos L * cos (S-n))))


To set up a polar mount you must set three different positions before you'll be able to track the clarck belt satellites.

First your dishes polar mount must have its axies aligned with the north/south axis of the earth, for proper recption of all communication satellites in the clark belt. On the back of most polar mounts there is a flat plane. This is what you use as a sighting reference for your aligning it with the south/north polar axies of the earth. Remember the dishes polar mount (dish pointing) towards the south. Also remember to adjust your compus south/north readings for magetic variations.


The Declination Angle is commonly known as the angular distance from the earth's equatorial plane intersecting the earth, with your dish positioned at some particular point on the earth. The declination angle can be set by placing an inclinometer on a flat surface on the rear of the big dish, which is parallel to the line between the rim of the dish until your reading equals the site latitude plus declination. Note: Declination = Zenith - Axis it is best to use the axis nubmer instead of the latitude as this number has been adjusted for your exact site location. It is also possible to put the inclinometer on a flat board on the front surface of the dish if you can't find a flat surface on the back of your dish. This board must be flat on the rim of your dishes top and bottom.

The Polar Axis is set by placing the inclinometer on the polar axis bar and adjusting it till you get a reading that equals the site latitude. As you can see from the chart below the latitude numbers are slightly different by the Axis numbers. This is becuase the Axis number here have been adjusted for your exact site location and are a little more precise. Therfore use the below Axis numbers for adjusting your Polar Axis.

(Note: Declination = Zenith - Axis)

Latitude
Axis
Zenith
Declination
5
5.13
5.80
0.67
10
10.26
11.70
1.44
15
15.37
17.60
2.23
20
20.47
23.40
2.93
25
25.57
29.20
3.63
26
26.58
30.30
3.72
27
27.59
31.50
3.91
28
28.61
32.60
3.99
29
29.62
33.80
4.18
30
30.63
34.90
4.27
31
31.64
36.11
4.47
32
32.66
37.25
4.59
33
33.67
38.38
4.71
34
34.67
39.52
4.85
35
35.68
40.65
4.97
36
36.69
41.78
5.09
37
37.69
42.90
5.21
38
38.70
44.03
5.33
39
39.70
45.15
5.45
40
40.71
46.27
5.56
41
41.71
47.38
5.67
42
42.72
48.50
5.78
43
43.72
49.61
5.89
44
44.72
50.72
6.00
45
45.71
51.82
6.11
46
46.71
53.92
7.21
47
47.70
54.02
6.32
48
48.70
55.12
6.42
49
49.70
56.21
6.51
50
50.69
57.31
6.62
55
55.66
62.72
7.06
60
60.59
68.06
7.47
65
65.52
73.32
7.80
70
70.43
78.52
8.09
75
75.33
83.64
8.31
80
80.22
88.69
8.47