The Antenna
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The Honeysuckle antenna in fog early one morning. Click image for a larger photo – and click here for an even larger photo – or here for one that’s been slightly straightened and cropped. (This would make a fantastic desktop picture.) Photo: Hamish Lindsay. |
The 26 metre (85 foot) diameter steerable antenna was designed to be versatile – to be able to slew quickly enough to track spacecraft in Earth orbit (it could move at 3 degrees per second) and also be accurate enough to track spacecraft for hours at a time at lunar distances.
The Honeysuckle antenna was a cassegrain design – the incoming signal was focussed by the 26m primary parabolic reflector onto the secondary sub-reflector (at the top – supported by the quadrapod – the four-legged structure.) The signal then was reflected back down into the waveguide, through the hole in the centre of the dish, to the low noise amplifiers and then to the receivers.
The 20kW S-Band transmitter, coupled with the narrow beam width of the antenna, was ideal for communicating with spacecraft at lunar distances.
The Honeysuckle antenna used an X-Y mount – two axes at right angles to each other – enabling it to track a fast moving spacecraft directly overhead without interruption.
At the very top of the quadrapod was the Acquisition Antenna used to help in acquiring low-earth orbit, fast moving spacecraft.
