Modified Polar Mount

Polar Mount Diagram
Figure 1: Angle terminology used here to describe polar mounts

Wherever you are on the earth's surface, all the "visible" geostationary satellites can be traced by an arc running from east to west across the sky with it's apex exactly due south of you (north in the southern hemisphere). The further you are away from the equator the lower in the sky the geo-arc appears. The purpose of this article is to set up your antenna mount to trace this geo-arc

Polar mounts are set up initially with the antenna facing the highest point of the visible geo-arc (true south in the northern hemisphere). In this 'apex' position the antenna can be driven by an equal amount to the east or to the west.
General Alignment Guidelines
(A) Adjust the polar elevation angle to peak signals from satellites located at or near the geo-arc's apex.
(B) Rotate the whole mount assembly around its mast or pillar when peaking signals from satellites far from the geo-arc's apex. That is to say trimming the north/south orientation.
Quick Alignment Method
(1) Obtain the modified polar mount angles for your latitude using the Satmaster Pro Demo
(2) Again using the Satmaster Pro Demo, find the elevation angle of a convenient receivable satellite about 30 degrees from the geo-arc apex. Call this SAT-1.
(3) Ensure the mounting pole or mast is vertical and set the antenna to its apex position facing due south. This corresponds to a true azimuth of 180 degrees in the northern hemisphere. If using a compass, remember to include magnetic variation for your location. Remember, compass bearings are automatically calculated if you download the Satmaster Pro Demo.
(4) Set the polar elevation angle (or the equivalent polar axis angle whichever is the most convenient to measure).
(5) Set the apex elevation, (or the equivalent apex declination). The small, declination offset angle is transparently set. If an offset focus antenna is used, subtract the offset angle from the apex elevation (or add to the apex declination).
(6) Connect up a wideband signal strength meter to the LNB (for DIY you can use a live signal monitoring hook-up).
(7) Monitoring the resultant dish elevation angle rotate the dish around the polar axis until it matches that computed for SAT-1. Hold this position and slowly rotate the whole assembly around its mast until maximum signal strength is obtained from SAT-1 and temporarily clamp. This trims up the north/south orientation of the antenna by exploiting the station keeping accuracy of SAT-1. Optimize the feed focal length at this stage.
(8) Move the antenna back around the polar axis until signals are detected from a satellite close to the geo-arc apex. Call this SAT-2. Fine trim the polar elevation (or polar axis) for maximum signal strength from SAT-2.
(9) Move the antenna back to SAT-1 and further trim for maximum signal strength by slightly rotating the whole assembly round its mast, thus trimming the north/south orientation as in 7.
(10) Repeat steps 7 to 9 as often as required for consistently peaked signals from both satellites. It may be necessary to temporarily tighten adjuster bolts at each stage.
(11) Check the received picture quality and tracking over a number of satellites and when satisfied fully tighten and grease adjuster bolts. Recheck signal strengths in case final tightening has affected alignment. Loss of signals from certain satellites may be due to a line-of-sight obstruction. Remember microwaves behave like light waves, they can't travel through walls or trees.