Parkes to Sydney

The Voice, Telemetry and Television pictures of the Apollo 11 Moonwalk were relayed from the Parkes Radio Telescope to Sydney via the PMG’s broadband radio (microwave) network.

Overseen by the PMG, technicians from the PMG (Postmasters General Department) and AWA (Amalgamated Wireless Australasia) installed the necessary microwave links to get telemetry, which included voice and the slow scan television, from the radio telescope to Sydney Video at the OTC gateway exchance at Paddinton in Sydney.

The closest point of entry to the PMG microwave network was the radio tower at Mount Coonambro, some 28km SE of the telescope and ESE of Parkes township (148°20'01"E, 33°15'06"S).

In order to link to Mt Coonambro, two portable microwave links were installed on the link tower adjacent to the Radio Telescope –
• an AWA 7Ghz portable outside broadcast system,
• and an EMI ML6B system (using 4 foot diameter mesh-wire dishes) loaned by Sydney commercial television station TCN-9.

One was prime, the other a backup. Once installed, the system was tested for several weeks before the mission. (See below for Warren Berkery’s notes on installing that link.)

From Mt. Coonambro, the microwave signal went via a 4GHz link to the PMG radio tower at West Orange, and then via 6GHz link to the PMG radio towers at Yetholme, Blackheath and Kurrajong South. From Kurrajong South, the radio link went to the Redfern Radio Terminal in the inner southern suburbs of Sydney – and thence to Sydney Video at the OTC gateway exchange in Paddington.


microwave links

An overview of the microwave signal path from the Parkes Radio Telescope to Sydney Video for the Apollo 11 EVA voice, telemetry and television.

Large, Larger.

microwave links

This schematic of the links from Parkes to Redfern (in Sydney) was passed on by PMG technician, Gordon Bennett to John Sarkissian at Parkes in 1999. John photocopied the chart in A3 segments and it was reassembled by Colin Mackellar.

The schematic had been commissioned by Geoff Foote, team-leader of the small group of Technicians from the Postmasters General Department Radio Section who were responsible for the links.

Click on the portion above to see the full chart (500kb) or here for a larger (2MB) image.

microwave links

The two dishes on the old link tower at the Parkes Radio Telescope.

The TCN-9 EMI ML6B 4GHz link with the wire mesh dish is at the bottom of the picture. The AWA 7GHz link is at top.

Image combined by Colin Mackellar from two frames of film taken from an Australian Information Service film found by John Sarkissian showing the preparations at Parkes.


The Parkes to Coonambro microwave path as recalled by Warren Berkery

Personal background:

Warren Berkery served a technical traineeship at AWA Ashfield from 1956 to 1960 and studied for the E&C Certificate and TVCoP.

I served as a technician with TCN9 television from 1960 to 1964, then as a Technical Officer with AWA Woomera from 1964 to 1968. I served as a team leader and console operator on the FPS16 tracking radars at Red Lake and Mirikata, delivering real time precision 3D position data on WRE and DoS missile testing, research rocket launches and ELDO test launches.

The Red Lake FPS16 was also a critical site involved in NASA Project GEMINI launches and early project APOLLO tests.

In late 1968 I decided to return east for family reasons. I applied for a position at Honeysuckle Creek, but do not recall an offer of work, so did accept an offer to return to TCN9 as supervisor of Outside Broadcasting.

In this role, I was responsible for operation of portable microwave links.

During 1969 a senior telecoms engineer who I recall as Fred Hailstone (or similarly meteorological surname) contacted the TCN Chief Engineer, Les Free querying the availability of a TCN portable microwave system over the period of the Apollo 11 Mission to integrate the Parkes Radio Telescope into the NASA network.

The TCN OB links were EMI ML6B ‘portable’ microwave link systems. Portable was somewhat of a euphemism with a complete system weighing in at about 600kg. The operating frequency band was 4460 to 4580 Mhz continuously tuneable, transmitter power was 3 watts, gain of the 4ft diameter open mesh parabolic dish circa 28db and Rx NoiseFigure 18db. This was the way of the world circa 1969.

But the ML6B was a proven performer over long haul paths. It served the Mt Buffalo to Mt Blackjack path (160 km+) for the 1960 Melbourne Cup pool telecast without a hiccup.

Fred H took the specs on board, calculated the path loss and Rx field strength as well as the Fresnel zone clearance and agreed to the PMG’s installation from Parkes RT to the PMG site at Mt Coonambro, thence into the PMG bearer system to the NASA control centre at OTC Paddington.

My physical involvement apart from delivering the 600kg package to somewhere in Sydney was to travel to Parkes and to Mt. Coonambro to tune the Tx and Rx klystrons. The only occasion I recall where OB link installation was a collar and tie event.

Fred H also commissioned a second independent link system. This was an AWA 7Ghz OB portable system provided by AWA with installation supervised by “Maurie” Menier, a well known character in the TV Engineering field in the era and a pleasure to work alongside.

I was informed in the lead up to the landing that while the AWA link gave marginally better S:N performance, the EMI gave superior hum and base-line performance and was selected as prime on that basis.

So when I viewed the moonwalk in Studio 1 at TCN TV in Sydney, I knew that I had made my contribution to the major event of the era.

Warren Berkery.

microwave links

This photo of the TCN-9 EMI ML6B 4GHz links in use at Red Hill in Canberra was supplied by Ian Mackenzie. The links were regularly used to help telecast election results.


The Blackheath tower in January 2009. It has quite a bit more on it now than it did in 1969. Photo: Colin Mackellar.


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