Some satellite woes at the station

Question

At the radio station where I work, we've been having problems with our satellite receiver (a Wegener iPump 4062, we're a Jones affiliate.) We had to replace the unit twice after severe thunderstorms wreaked havoc on them, and the electrical issues have been fixed after that. However, it seems we're having some problems with the signal cutting out around sunset and coming back toward sunrise. Could the signal fade be due to the satellite itself maybe moving a tiny bit while in orbit, or is it more likely a dish issue? The LNB has been checked and all's well.

Answer 1

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.