Some satellite woes at the station

the index of refraction of air changes at sunrise and sunset. this would change the appearent location of the satellite, but only if it is near the horizon or other nearby obstruction. problems of this sort are normally associated with STL paths which are nearly horizontal and graze over ridge lines or near buildings. (technical term for this is fresnel clearance). if the view of the satellite from the dish is unobstructed, then it should have little or no fresnel interference.

however, if it is mounted on a building, then it is very possible that temperature and other climatic variation causes the building to move slightly. most buildings are not sufficiently rigid to hold a large dish in good alignment, especially the roof of a building several stories high. this could be aleviated by going to a SMALLER size dish where the alignment is not as critical. the building could then have some sway without the beam of the dish going off-satellite.