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<blockquote data-quote="Channel Hopper" data-source="post: 1034178" data-attributes="member: 175144">That might be where you are going wrong, but I don't have the specific mathematic skill to confirm it.The Clarke arc parameters are determined by the periodic rotation and the gravitational pull of the total mass of the planet in one direction. Since earth is not spherical the arc dimensions are determined by the average radius at a position somewhere north or south of the equator.This means the actual arc is closer to the surface of the earth owing to the bulging and any polarmount installed elsewhere other than the equator, or the poles (not that they would see the geostationary satellites) needs revised adjustment of the elevation/declination settings to track correctly from horizon to horizon.This mis-tracking is only likely to affect the largest of steerable dishes and a small motor at the feed or on the elevation will correct the focal error at the extremes without resorting to a bespoke earthshape design of dish mount.</blockquote>

[QUOTE="Channel Hopper, post: 1034178, member: 175144"] That might be where you are going wrong, but I don't have the specific mathematic skill to confirm it. The Clarke arc parameters are determined by the periodic rotation and the gravitational pull of the total mass of the planet in one direction. Since earth is not spherical the arc dimensions are determined by the average radius at a position somewhere north or south of the equator. This means the actual arc is closer to the surface of the earth owing to the bulging and any polarmount installed elsewhere other than the equator, or the poles (not that they would see the geostationary satellites) needs revised adjustment of the elevation/declination settings to track correctly from horizon to horizon. This mis-tracking is only likely to affect the largest of steerable dishes and a small motor at the feed or on the elevation will correct the focal error at the extremes without resorting to a bespoke earthshape design of dish mount. [/QUOTE]

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