When the front face of the dish is vertical, the beam elevation
angle towards the satellite is the offset angle.
For beam elevation angles lower then the offset angle the front face
of the dish needs to be tilted forwards. For beam elevation angles
higher then the offset angle the front face of the dish needs to be
tilted backwards.
Contributed by a visitor to this web site...
Thanks for a most useful site.
I just installed my first dish, for Astra
28.2E at home, and found your calculator was just what I needed.
My satellite receiver kit was supplied with 58cm offset elliptical dish
which had a very poor angle indicator on the elevation mount, and I was
unable to find any signal at all! The offset angle of the dish was not
marked on it or given in the instructions.
I decided to measure the offset angle with light.
With the dish on its back, I placed a chromed dog tag ( a small vanity
mirror would do) in the middle of the dish. I removed the LNB and held a
laser pointer in the center of the clamp, pointing at the tag. I then used
the line of the reflected beam to mark a piece of card which I had fixed to
the dish with masking tape.
Using the required elevation figure from your calculator and a protractor,
I marked what would be a vertical line on the card, and used the dog tag and
some cotton thread to make a plumb-line against the vertical line on the
card.
Back up the ladder, it was easy to set the elevation and I found a signal
immediately. The elevation was spot-on.
Without a laser pointer, you could find a sight line by looking at the
reflection of the LNB in the mirror.
I have made a sketch of the dish, and you could add it to your site for the
benefit of anyone else with a similar problem.
Or do you know an easier method?
Wishing a Merry Christmas and a happy New Year to you,
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