A receiver and amplifier receive the radio waves from the sub reflector, and make these weak radio waves strong enough to be recorded and turned into electronic signals.
Most antennas are made in the shape of a dish to collect and reflect the radio waves to the sub reflector, in the same way as a curved mirror focuses visible light to one point.
大多数天线被制成碟形，用以收集和反射无线电波至亚反射器，就像曲面镜将可见光聚焦于一点一样。
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The reflector action of such a conducting layer makes it possible to build a radio telescopes that correspond exactly to optical instrument.