The Honeysuckle Creek Antenna



The Antenna in fog

The Honeysuckle Creek antenna in fog early one morning.

Larger photo – or here for one that’s been slightly straightened.

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. This design meant that there were two ‘keyholes’ to the east and west where the antenna could not point.

 

HSK Antenna

Horizon profile, West to East.
Drawn and scanned by Hamish Lindsay.

Larger. Largest.


HSK Antenna

Horizon profile.
Drawn and scanned by Hamish Lindsay.

Larger. Largest.


HSK Antenna

Horizon profile.
Drawn and scanned by Hamish Lindsay.

Larger. Largest.


HSK Antenna

Here’s Hamish standing on the apex of the antenna with his theodolite, surveying the Horizon profile.

Photo preserved by Hamish Lindsay, scan by Colin Mackellar.

 

At the very top of the quadripod was the Acquisition Antenna used to help in acquiring low-earth orbit, fast moving spacecraft.

 

HSK Antenna

The Honeysuckle antenna.


HSK antenna

The Honeysuckle antenna.

These two photos (particularly the lower one) show the X-Y mount of the antenna.
The transmitter room is the square structure directly below the dish.

Photos by Hamish Lindsay, scan by John Saxon.


HSK antenna - X-Y mount
Photo: Hamish Lindsay


For Apollo, all television, tracking, remote commands and voice transmissions to and from the spacecraft were handled by a single radio carrier wave through a new ‘Unified S-Band System’.

Downlink data, monitoring several hundred measurements such as astronaut heart rate, cabin pressure and temperature was transmitted in real time.

From the tracking stations data and voice was set through NASCOM to the Goddard Space Flight Center in Maryland to be processed and passed on at 2400 bits per second to MCC computers at Houston.

Uplink data from Houston to the spacecraft, such as guidance commands were passed at 1200 bits per second via NASCOM and the command tracking stations...”

 

For more info on USB see The Unified S-Band Technical Conference proceedings.