| 摘要 |
<p>Broadcasts from a geostationary satellite are received by a highly directional antenna with a parabolic reflector. The antenna is set to the correct elevation and azimuth by a gauge which is attached to an alignment plate on the side of the reflector installation. This aligns a reference edge (16) on the gauge with the antenna axis. The gauge has a pivoted (11) plate (1) carrying a spirit level (8) and a magnetic compass (3). The plate has a pointer (9) which is set to the satellite elevation on a scale (15) and clamped by a screw (18). The compass is rotated bodily in the plate to set a pointer to the magnetic bearing of the satellite on another scale, and clamped by a screw (7). The antenna is then turned about its axes to centre the spirit level and bring the compass needle to the north/south marks. Fine adjustments of antenna direction are made for maximum received signal and the gauge is removed.</p> |
