By Reed M. Burkhart
The polarization angles of satellite dishes used for cable headends may have more error during the next few years than ever before. This is due to the diurnal variation of incident polarization angle, which is on an upswing recently due to heavy solar activity which should persist and worsen before abating. A combination of night and day time polarization alignment of cable headend dishes may be preferred by cable operators in some parts of the world where this effect is strongest. This paper describes the phenomena of Faraday Rotation which causes polarization mis-alignment. It identifies regions of the earth where cable headends would find the strongest effect and recommends methods to minimize degradation due to this effect. Prediction data from NOAA (National Oceanic and Atmospheric Administration) is reported, showing the anticipated peak period of polarization rotation to be early 1990.