To calculate the line-of-sight you will need to do some basic mathematics. You will be shown how to use the Microsoft Windows Calculator to perform the necessary calculations.

Where X is the height of the obstruction in front of the antenna and Y is the distance between them.
For example, if the obstruction is 8 meters high and 32 meters away from the antenna, you will need to perform the following calculation: arc tan (8/32) = angle

Use the Microsoft Windows Calculator to calculate your line-of-sight as follows:

1) Navigate to your windows calculator.
2) Choose View then Scientific.
3) Enter the height of the obstruction in meters and divide it by the distance in meters.
4) Choose the equals function.
5) Check the Invert box.
6) Choose the Tan function.
7) The result will be the minimum angle of your true elevation in degrees.
8 ) This angle should be lower than the true elevation angle of your antenna.
If you do not achieve a clear line-of-sight, relocate the antenna until this is achieved.

Or you can use this online tool... https://www.satellite-calculations.com/Satellite/Elevation.htm