Orroral Valley Tracking Station, ACT

Orroral remembered – by Ted Barnes

This a is collection of memories from my time at the Orroral valley tracking station. I worked there as an electronics technician from Dec 1968 to Dec 1969. Any errors of fact are due to 40 years of cobwebs in my nut.

I had heard about Orroral from my friend Pat Lynch who I had worked with in New Zealand. I had a neat job in oceanographic research, but I was getting married in Australia so I took a year off from my NZ job, which you could do with government jobs in those days, and called in to Orroral to see Pat and with some vague hope of a job. In the event I struck it lucky, they were just about to advertise two jobs, one on RF maintenance, the other one on tape recorders. The job interview consisted in large part explaining the equivalence of NZCS to HNC, as the people on the panel were not familiar with the then new NZ qualification. I took the RF job.

You also had to have a security clearance, from the CIA I think. I found out later they were very thorough grilling my referees in NZ.

To a kiwi lad the whole deal was amazing. I got paid twice what I got in NZ, (on the lowest technician pay rate), and they even paid $16/week for driving one of their cars to work. We got given a house in Canberra for 6 weeks while we sorted ourselves out. As it worked out my wife Leonie got a job in the office at Tidbinbilla, so we were both in the space business as it were.

Ted & Leonie Barnes in 1969.

Cars were shared with 1 to 3 others – The trip to work from Canberra or Queanbeyan took 3/4 hour so you got very good at judging to the last minute when you had to cross the bridge at the outskirts of town so as to clock in on time. About 1/3rd of the way was unsealed road, so on the way home from work you got your passengers together as close to the head of the queue at the time clock as you could so you avoided eating too much dust. It was always a mad race on the way home.

Orroral was run by EMI under contract to the Department of Supply for NASA. Consequently many of the staff were Poms that had had training in a military environment. Pat, me and one of the engineers were the only Kiwis there at that time. There were 3 shifts of operators, and a day shift of technicians and support people. There was actually not a lot to do. Things did not fail that much, and apart from upgrades, Pat and I spent quite a bit of time pulling things to pieces to see how they worked. This was condoned, provided things were operational 24 hours before needed. There was a huge amount of equipment redundancy so we could potter around to our hearts content quite often. It seemed to me that following the launch of Sputnik 1 the US got such a shock that they threw a blank cheque at this problem called space. At Orroral I felt like a kid with a free run in a lolly factory. So much totally cool stuff! Much of it of the type you would not see anywhere else outside of the space industry.

The Orroral Valley Tracking Station 26 metre antenna and operations building – looking to the south west. Click for 750kb version. Photo: Ted Barnes, 1969. Ted writes, ‘The white building was the eatery.’

The main building was roughly square with a small courtyard in the middle. A corridor ran around the middle of each side, so there were rooms with a view to the outside, and on the inside were rooms with no external windows, apart from the library which gave access to the internal courtyard. The administrative staff and the Station Director’s office was at the front by the main entrance, the main equipment room was at the other side of the building with a view of the big dish. A dock way and store took up most of one of the other sides. Other spaces included a lecture/meeting room, rooms for the RF, digital and the test equipment technicians, and a room with the teleprinters. A screened room housed a PB250 computer that was used for generating punched paper tracking tapes.

Other buildings included a white prefab where we had lunch, a building for the diesel powered generators, and mechanical workshop. Also the minitrack field had a building for its equipment. About 1km away was the transmitter building with the two disk on rod style uplink antennas. Further away up the hill was the building housing the CSG collimation beacon for the main dish.

Uplink antenna. There were two of these. Normally used on 148Mhz. The disc on rod design allowed wide band use from 120 to 155MHz. Could be used for various polarizations but fixed on RHC while I was there. Transmitters were AM using pulsed audio tones around 20kHz. There was two 5kW GE transmitters and two 2.5kW Hughes transmitters. Photo and text: Ted Barnes.

Spaced around were various other antennas. A pair of 16 yagi 136MHz antennas were alternates to the main dish. All the receive antennas fed back to data and tracking receivers in the equipment room. On the transmit side data and tracking signals were feed up to the transmit building so there were short RF feeder runs to the uplink antenna. These antennas were big. I remember on one occasion trying to find a corroded mounting by walking around on the yagi mounting framework kicking at things while watching down to a spectrum analyzer which was hung off the cherry picker.

Uplink antenna Two yagis, one for 122MHz , the other for 148 MHz. Driven by a 250 watt transmitter. Transmitter building and one disc on rod antenna in background. The only satellite I can remember using 122MHz was Alouette, a top side HF sounder. Photo and text: Ted Barnes.

The main 85’ dish was huge, the feed box was about a 2m cube, and you could get inside it if you had to. I only had to do this once to swap out a 400MHz preamp. The original equipment for 400MHz reception were parametric amplifiers, it was that long ago, and they were still there running as back up in 1969. And if you wanted to change a preamp transistor they were so expensive you need an engineer’s signature.

Main antenna, a 85ft dish, X-Y mounted so you have low slew rates on high passes. Electro-hydraulic drive. Equipped for monopulse tracking on 136 and 400MHz. There was provision for a 1700MHz feed but it was not installed in 1969. There was a neat 8” telescope with 1000 line TV system to check pointing accuracy using stars. The small dish on the side is a gain standard. The yagi array in the background is a 136MHz antenna for use with geostationary satellites. Photo: Ted Barnes, 1969.

The contents of the store was amazing. The was spares for everything down to spare cases for HP counters and such like, and if they were out of stuff you tapped in the federal stock number on the teleprinter and it would turn up on the next plane.

The first day on the job I got asked to run a cable under the floor of the main equipment room. It was a standard computer room floor with tiles that could be lifted to get access to the cabling. Anyway away I went, and when I got to the other open tile a ring a faces looking down said, “You survived then”. “Why not say’s I” “Well there are snakes down there and nobody has been game to run that cable for weeks!”

You got to see a lot of squashed snakes on the road coming to work. Also a potential hazard was hitting a wombat or a kangaroo. I got a big fright one day nearly hitting a big kangaroo that was warming its feet standing in the middle of the road. It was not in any hurry to move so there were some serious black marks laid down.

Because the humidity around Canberra is normally very low, and the cars had vinyl covered bench style front seats, electrostatic shocks were an enduring hazard. You got to drive around the site quite a lot if you were doing RF things, so there tended to be boot imprints along the bottom of the drivers door where people tried to avoid getting plated.

Lightning is a real hazard at Orroral because everything is so dry. While I was there, several serious strikes took out buried cables and blew big holes in the ground.

Antenna servicing using a cherry picker. Technician in basket gives some idea of scale. This downlink antenna is a 136Mhz yagi array mounted on a hydraulically driven X-Y mount. The signals from the 4 groups of 4 yagis are combined with hybrids to generate the monopulse tracking signals as well as the sum and diversity channels used for data recovery. Photo and text: Ted Barnes.

After a few months on RF I got the chance to switch over to digital. This involved fixing the ADECS computer and the PCM DHE gear. The ADECS was a real orphan, one of 6 made I think, and full of dry joints.

Before a pass the whole RF / PCM / computer train would be made to lock up on dummy data from the collimation tower. Not infrequently the ADECS would fail and a data manager would come out in a big panic. Slamming the left hand door to make it work was not considered an acceptable fix. So I would re-solder a lot of transistors and wait for the next time. It also had a very temperamental tape recorder. It was supposed to work at 800 bpi, but the best it would do was 200bpi. At that density you could read the bits on the tape with a magnetic film viewer. Those were the days!

ADECS 37A. This was one of only two general purpose computers at the station. It had 4k words of 37 bit core memory with a further 2K on a drum memory unit. There was a paper tape reader and punch, a drum printer, and a 200bpi 7 track tape unit along with hardware dedicated to specific satellites. The operators consol was the IBM electric typewriter and a digital read out unit that used incandescent bulbs. The technology level was germanium transistors with one flip flop per board. This computer was used to extract some data from the satellite downlink and forward it at slow speed (2kb/s) in real time to GSFC in the US. Amongst other satellites it was used with OAO-1, the grandfather of the Hubble space telescope. Most data was sent back on 7 track ½” tape. The other computer (not shown), was a Packard Bell PB250. This was kept in a screened room and only used for making antenna tracking paper tapes as a back up to the normally used monopulse tracking. It had a 2K plated wire serial memory. Photo and text: Ted Barnes.

ADECS 37A instruction sheet. Scan: Ted Barnes.

I got very interested in the whole bit / format sync business, and in a lot of ways all that started here. The circuits used in the bit syncs in particular fascinated me. Seeing a band of noise coming in and an orderly line of bits coming out was amazing to me. All taken for granted now, and usually buried deep in a chip that does lots of other stuff as well.

Sometimes it was hard to keep a sense of perspective on the scale of things. On one occasion an operator was having me on that a receiver must be faulty because the signal meter said -140dbm and the book said it should be -139dbm. “Look” says me. “You have a tin can out near the moon somewhere, running about as much power as a small torch bulb, and you are worried about 1 db! All the data lights are locked up so panic not.” On another occasion I got roused about a supposedly faulty transmitter. The digital display showed 148.199999 and the book said it should be 148.200000, thus the transmitter was faulty. That had a simple fix. Bias up the transmit crystal 100 Hz so there was lots of zeros showing.

There was lots of margin usually, especially on the uplink. On one occasion the stow pin jammed the antenna in the zenith position. The commands were sent anyway, and everything responded as it should, even though the satellite was 2000km away on the horizon and so receiving a minor side lobe of the transmit antenna. As I recall the operators had a system of demerit points for stuff ups, and could get credits for fixing other station’s booboos. One hazard to avoid was placing the spacecraft into a roll manoeuvre and have it go over the radio horizon before you turned the thruster off. The Orroral operators were often in credit. Not sure if there was any sort of bonus for them.

A lasting impression I have is how hot it was in the summer, but hey I came from Wellington, NZ. The winter was not so bad to my mind.

If you have 7 track tape recorders you have 7 oscilloscopes to monitor things! Photo and text: Ted Barnes.

There was only one occasion I can remember not being able to get to work because the river was up. I think there was a shift of operators stuck at the station for a couple of days. Normally the ride to and from work was uneventful, but on one occasion I decided to take a short cut which turned into a drama.

One of the people I frequently had in my car was Gaye Moore. She lived on a farm way past Queanbeyan, so had to travel in a big V from her place to Queanbeyan then to the station. For some reason I was to have the car that night, so seeing this dotty line on the map from the station to near her place we took off across country. After travelling along a rough track for a while we came to a ford at a stream. There was a large dragline nearby which did not register at first. I nosed into the water which was about 10m wide. There was an appalling bang and the bonnet seemed to disappear in a cloud of spray. The rats had removed the roadway. I floored it and with much lurching and banging we made it out the other side. I was pretty shaken by all this, but continued on.

The road became a track on the side of a steep hill. A hairpin bend came up. Oops, no brakes; all wet. We slithered around the corner somehow. A few miles later the cloud came down and the visibility reduced so much I had to stop frequently to see if I could see any tire tracks in the grass. After what seemed to be ages we came to a serious river. One of those fords where they have posts marked off in feet of water depth. The first thing was to decide which side of the posts the roadbed was. In the event I guessed right and we started across. The mist meant you could only just see the next post and I had no idea how wide the water was. The depth was such the car periodically started to float and the back would slew around downstream as we lost traction. But we made it, but it took about an hour more than expected. I never went that way again.

The people at the station were a good crowd. There were quite a few BBQs and other social events after hours, but Leonie and I were rather constrained not having a car so we got to walk a lot. We saw an opportunity do serious saving toward a house. At that time there were all sorts of good deals going trying to get people to live in Canberra and settling down there was a real possibility.

Toward the end of 1969 I had to make the decision to say, or go back to my job in NZ. It became clear after the first moon landing that the money for all things space started to dry up big time.

Also we had a presentation about the TDRSS system then being designed which would reduce the need for non US ground stations and so reduce NASA’s costs. So I decided to quit when my year was up and go back to oceanographic electronics. However that year stands out as a magic time, and had a strong influence on my interests and career from then on.

4th September 2008.

One big cherry picker! Antenna is HF tri-band yagi for WWV. Station time was derived from a rubidium clock which kept time to around +/- 5 microseconds, which we thought was amazing. Periodically people would arrive with a couple of cesium clocks to check its accuracy. Photo and text: Ted Barnes.

Photos by Ted Barnes.
Photo restoration by Colin Mackellar.