Ceduna 1 Synchro Resolver Drama

Tony Fisher Lived to Fight Another Day

After reading about the twin dishes proposed for Jamesburg in an earlier article about Jamesburg Earth Station in the US, Tony Fisher wrote back with this story:

I wonder if the 100ft Ceduna 1 dish was also specified for this capability? It had a tracking speed of an incredible 0.3 degrees per second in both Azimuth and Elevation, although I only ever once saw it run in “full flight”, and then quite by accident. I always understood this was to enable the dish to track launches coming over the eastern horizon, as back when it was built, Ceduna was the first ground station to be able to communicate with the launch vehicles as they came back into radio contact having passed through the atmosphere.

Harking back to my “accidental” full speed operation of the double drive motors, – during my early days at Ceduna, as a TO1 and still quite fresh out of training, – Ceduna 1 had a very rare “out of service period” just after the 30m Ceduna 2 facility was brought online. I was given the task of the full “service book” maintenance routine on the Ceduna 1 Synchro Resolver Manual Control Panel, which I diligently set about at the start of my maintenance day shift. Unfortunately I forgot to manually lock the brakes on.

End result, with a gently breeze running throughout the day, the dish was gently “blown around towards the POR”, in stark contrast to where it should have been – on the IOR. Towards the end of my shift I was initially quite pleased with myself, having got through the massive task of dismantling, cleaning and re-assembling all the “clockwork” components of the synchro resolvers and the manual control wheels, getting everything back together in the precise “pointing” position, – ready to put the large synchro resolver chassis back into the rack and “plug it back in”. Going around the end of the control room rack suite however to reconnect the myriad of massive Cannon connectors, I glanced out the window where, – to my horror I saw the 100ft dish “pointing” the other direction.

Now I had a problem! What was going to happen if I plugged the syncro resolver antenna position controller back in? I figured one of 3 things.

  1.  Emission of “Grey electrons”, – hmmm quite possible.
  2. A screaming rotation of the syncho resolvers in the controller to bring it back into alignment with the actual position of the dish, or
  3. Maybe, just maybe, the antenna would drive back to align with the controller.

End of shift! What to do? Nothing ventured, nothing gained! Plug it in!

Every-one stood around to watch me suffer under utter humiliation. No-one breathed while I plugged it in and switched the power back on, – but to everyone’s amazement, None the least my own, the dish motors arced up to full speed and literally screamed. Much to my relief, – the Ceduna 1 antenna drove back to its IOR pointing location, only slowing momentarily as it converged with the synchro resolver positions and the Nixi Tube display positions in the controller. I had lived to learn another day!

Thanks to my many mentors and “associates in crime” including: “JG”, “ERW”, “BLA”, “PWB”, “PM”, “CE”, just to name a few. Those were good times indeed.

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9 thoughts on “Ceduna 1 Synchro Resolver Drama

  1. I heard today that Moree Earth Station was initially design with a two dish capability like Jamesburg Earth Station for the same reason. Its speed was fast to be able to scoot back for the next pass..

    • I hadn’t heard that (I wasn’t at Moree from the beginning, though: only arrived in June, 1970), but colour me doubtful. Unlike any of the other .au earth stations, Moree 1 had an hour angle/declination drive (instead of azimuth/elevation), and the declination axis was driven by a hydraulic piston, giving it limited movement in that axis (+/- 10 degrees or so, I think). Such a design would imply that they expected the satellites it was tracking would be in geosynchronous orbit. The whole thing was also as slow as a wet week in Melbourne, so switching satellites would take quite some time. You’d probably need three dishes.
      It’s possible the 2-dish concept was considered at a very early stage, though.

      • Possible, I was at the OTVA lunch yesterday when a few people mentioned it. When you look at the timeline, it is obvious that it had to have been on the drawing board. Syncom 3 was launched late in 1964.
        Wikipedia says: “Syncom 3 was the first geostationary communication satellite, launched on August 19, 1964 with the Delta D #25 launch vehicle from Cape Canaveral. The satellite, in orbit near the International Date Line, had the addition of a wideband channel for television and was used to telecast the 1964 Summer Olympics in Tokyo to the United States.[3] Although Syncom 3 is sometimes credited with the first television program to cross the Pacific Ocean, the Relay 1 satellite first broadcast television from the United States to Japan on November 22, 1963.”
        Intelsat I was launched 6 April 1965 – well before TV on intelsat. It did however open the way for the future.
        Pressure from the US for the Apollo moon mission was building and since Moree was opened sometime before or around mid 1968 (can’t remember – sorry), I suspect that these issues had been part of planning. I would love to know more about this aspect, but at yesterday’s lunch it was very clear that at least the original design of Moree was with 2 dishes! I will try and track down the people talking about this and get more info.

  2. I’d be interested to see what you can dig up. I was at Moree from June, 1970 to December, 1972, and I don’t recall ever hearing about it. Remember, too, that my knowledge (or lack of it!) comes from being with the other station techs, most of whom had been there since the station opened in 1968. If there ever was a 2-dish plan ‘B’ for Moree, it would have been much earlier than that, and probably known only to the engineers (who we never associated with, of course).

    …..Ron Murray

  3. I never heard of a two dish arrangement. Was at Moree all of 1967. Agree with the other posters that Moree 1 was as slow as a wet week!

    • I can only tell you about a conversation at the OTVA lunch last Friday with the engineers that were planning the site in the early days – it was on the cards but never happened. I expect the speed that Moree happened at meant that the dish was totally different and not horizon to horizon. Jamesburg was a longer build process and thus they chose a dish that could point anywhere. I really have to find the name of the OTC engineer and have a long chat.

  4. Actually, Ceduna 1 could move faster than was specified (although it was not a great idea to do so). The 97 foot dish moving at full speed was a scary sight. Tony, I don’t think I was there the day of your “incident”, but I have certainly see that thing move quite fast on other occasions!

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