My Job
I will try to describe the work I found myself involved in. This may be a bit technical at times but I hope to give and idea of the electronic world of the 1950s.
So, after the turmoil of settling in, everyone set about organizing his own specific daily work. The Met. boys had to organize a routine of shifts to cover 24 hours, and as it was much the same work that they had been doing back in New Zealand, it was soon set up.
My own work was slightly different to that which I had been accustomed. Once I had set up a maintenance program there was not a lot of actual electronic work to do. If the gear behaved itself, then apart from simple routine maintenance I was free to do other work.
To start with however there was plenty to do because I had equipment to install for the International Geophysical Year (IGY). The main item of equipment to be used was the seismograph. The rather sparse instructions I had been given said, in part, "set the seismometer on a firm base and run the connecting coax cable to the seismograph".
The seismograph, which is the recording part of the system, had to be in the Met building and as I hoped to have the seismometer head reasonably handy this restricted the area in which to find a "firm base". In fact there was no easily available "firm base" in the immediate area, as it was all volcanic soil. It was great for growing grass but no good at all for mounting a seismometer. Therefore, we would have to make a "firm base". I mentioned this to Noel (the handyman). His eyes lit up and he said, "leave it to me".
Sure enough he soon cranked up the D7 bulldozer, which was part of the original Raoul installation, then he and machine disappeared into the bush. Some days later he said rather proudly "OK, your platform is ready".
There it was, a 3m x 3m x 45cm thick concrete slab. He must have used up the entire year's supply of cement!
On this magnificent plinth I placed the seismometer, which, being only 30cm high by 12cm across looked a little lonely. I dug a trench for the cable and wired it up.
Unfortunately, after running a few tests it was obvious that something was wrong. I eventually found that the seismograph itself was broken. Part of it was a tiny mirror supported by hair-thin copper wire and one of these wires had broken during transit. I managed to make a temporary repair and started the system up.
Now the seismograph is supposed to record remote earthquakes as tiny squiggles on a strip of 35mm photographic film. I had a sample of this film with a typical trace on it so I would know what to look for.
My trace looked nothing like the sample. My trace showed what appeared to be a series of regular earth tremors occurring about every 7 to 10 seconds and the traces were large enough to mask any real earthquakes. We puzzled over this for several days until someone suggested the interval was about the same as that of the waves hitting the beach. That was it
The seismometer was sensitive enough to pick up the vibrations caused by the waves even though the beach was nearly a kilometer away. I had to tell a disbelieving Noel that his magnificent plinth was not firm enough. That it vibrated when waves hit the beach.
There was nothing else for it. I would have to find another site. Eventually after much searching through the bush I found an outcropping of an old lava flow and after spending several
Chris helpingme dig the cable trench. Orange trees in background.
Noel, who felt he had to do something to mark his plinth, installed a damaged toilet on it. As far as I know it is still there and will be something for future visitors to puzzle about if they stumble over it in the bush.
Some time later, I wandered up to the seismometer site to check all was OK. All was not OK.
My laboriously dug cable trench had been dug up and the cable exposed. I heard a noise in the bush and a little further on I found one of Dick's sows, complete with half a dozen piglets, busily rooting about in my cable trench.
I guess it was a nice soft place for her to teach her offspring the finer points of pig rooting.
Now this effort of hers was undoing all my hard work and did not do my temper much good. I started yelling at her and she took off at a run with her piglets doing their best to keep up.
She reached the road and started heading for the farm and the safety of her sty. I followed still running and yelling and throwing stones, reasoning that she would remember all the hassle and not come back.
However the piglets fell behind and started squealing. At that she stopped dead, swung round and let out a loud growling snort.
I stopped, and we looked each other in the eye, then she wheeled round and trotted off at a more sedate pace with her piglets trotting behind.
I let her go and I think we both learned a lesson. She never came back, though thats probably because Dick improved the security of her sty.
THE SEISMOMETER (Boring Technical Bit)
The seismometer, which is the name for the whole installation, consists of the detecting head, the installation of which gave so much trouble, and the recorder or seismograph which had the broken mirror support. The two are connected together by coaxial cable.
The head is essentially a solid mass suspended on two sets of phosphor-bronze leaf springs. The mass made of magnetic material, has a very strong magnetic field and is also very heavy.
This suspended mass is free to move up and down on its springs. Surrounding the mass, very close to it but not touching, are thousands of turns of very fine wire. These are attached to the body of the instrument.
When operating, the unit sits on the ground with nothing moving and no output being generated. Should the ground move, for any reason, the body of the instrument also moves, but the suspended mass, because of its inertia, stays still.
The moving coil cuts the magnetic field and a current is generated in direct proportion to the rate of movement. This current is fed directly to the seismograph. There is no amplification.
The seismograph, housed in the Met office, records the current vibrations produced by the head using a photographic method. Firstly the current is fed to a small coil suspended between the poles of a strong horseshoe magnet by very fine wire. Should an alternating current flow (which is what the earthquake waves produce) the coil will vibrate in sympathy.
Now the coil surrounds and holds a tiny mirror so the mirror vibrates in sympathy with the incoming current. A spot of light is focused onto the mirror down a tube about 40cm long.
This is reflected back to a fixed mirror that reflects it back down the tube, past the suspended mirror and out of the detector.
Here it is focused again to a precise dot of light on a strip of 35mm photographic film.
The original movement of the suspended mirror is magnified many times by the time it reaches the film. Even so, the normal trace on the film is physically only 2 or 3 mm wide. The film is mounted on a drum that rotates six times in 24 hours thus producing a continuous trace with six tracks across the film.
One of my daily duties was to change the film, develop the used one and note the time of any recorded quakes. This information was then passed to the seismic observatory in Wellington as part of the daily Met. report.
The object was not to record the quakes on Raoul as these simply overloaded the system, but to record and time quakes in other parts of the world.
Raoul was another base in a world-wide web that allowed accurate pinpointing of tremors and identifying their type right round the globe.
Timing the seismograph was very important, because the more accurate the timing of the arrival of an earthquake wave, the more accurate the location of its origin.
Timing was done by manually injecting a small current through the deflection coil so as to cause a mark on the trace. This was done several times a day, and the time noted.
I used a Morse key for this purpose and would listen to WWV time signals, counting the seconds and hitting the key at the right instant.
I believed I could get accuracy to within a tenth of a second!! However the experts in Wellington sent us a special chronometer on the mid-year re-supply boat which did the job automatically.
All I had to do was keep it wound up and check its accuracy. I still think my way was better!
TIDE GAUGE.
Another installation I had to make was a tide gauge. Again the instructions were simple enough. "Install the pressure head below max. low tide mark in as sheltered a place as possible". This would be in order for a harbour installation where it could be attached to a wharf pylon or something similar. It was not so easy on an island that had no calm or sheltered areas at all.
The pressure head was connected to a clockwork-driven recording chart by a length of copper tubing. The system required a weekly visit to change the chart and wind the clockwork motor.
I believed that boat cove would be the best place as it was at least a decent dent in the coastline and therefore should be more sheltered than Fishing Rock, which simply stuck out from the shore.
Bad idea!
It was good fun installing it as I could put my underwater skills to good use, but sure enough, on the second trip to replace the recording chart, I couldn't find the pressure head at all. The recorder was fine as it was well out of the way but there was no sign of the rest of the equipment. I eventually found a tangle of copper tubing on the rocks some distance away with the pressure head still attached.
After several attempts at different sites in Boat Cove, all with more or less the same results, I had to try the only other site at Fishing Rock. To the surprise of all it worked well.
This was probably because I found a neat, deep, crevice in the rocks for the head and was able to run the pipe up the loading ramp and concrete it in place.
Anyway, it stayed in place even through the worst of seas that regularly pounded Fishing Rock. The only drawback was, that that particular excuse to visit Boat Cove disappeared.
Boat Cove was a great place to visit . It was fun negotiating the road which was just a glorified track through the bush. We often used the tractor for these trips, it was slow, but there was usually no hurry.
The tractor rumbled along at a gentle pace as set by its hand throttle and this fact gave me a real fright when I let my attention wander. It was a flat straight stretch of road with a steep bank rising on the left side. I wasn't paying much attention, probably gazing out to sea, when the left front wheel drifted into the bank, the front wheels were pulled hard left and we started to climb steeply.
When the load came on the governor reacted by pouring on the power, which is what tractors do. All this took only a few seconds, one minute we were trundling quietly along the next we were trying to climb an impossibly steep bank under full power. I just had time to stamp on the clutch before we rolled, but I got a hell of a fright. Another lesson learned.
I often wonder if any one ever looked at those tide charts or thought about the effort that went into getting them.
COMMUNICATIONS.
All the information garnered during a day at the office had to be transmitted to Wellington. This was done by way of daily radio schedules.
Whoever was on duty when the sched. time came would set the equipment up and call Wellington.
We had two Collins 1 kilowatt HF transmitters and a good antenna system. For reception there was a pair of SuperPro receivers. So communications was usually very good.
The Wellington end was the Post and Telegraph international exchange, and when contact was established you asked for who ever it was you wanted and you were patched through using the normal telephone system.
We became quite familiar with the International operators as we talked to them several times a day. One in particular was our favourite, I never knew her real name as she was simply known as Blossom. She had a great personality and when she was on duty her cheerfulness was always a tonic.
All expedition members were allowed free phone calls to their families once a week and these were always used up. The only difficulty was getting people used to a simplex radio circuit, which means only one person can talk at a time.
The time honoured system of saying "over" when you had finished talking was the only way. It made for rather stilted conversations but people caught on in the end. Good communications was absolutely essential to the well being of the expedition and I made sure maintenance of the comms. equipment took first priority.
THE CYCLORAY RECORDER
(More technical stuff)
This diabolical piece of equipment was one of the most important items on the Island. Its job was to record the details of the data that the radiosonde transmitted back as it ascended through the atmosphere.
In operation the recorder produced, on a paper roll, a record of the balloon's flight. It did this by tracing out the temperature, pressure and humidity as they were transmitted by the radiosonde as it rose through the air. This recording method was the problem. It worked like this.
First there was a drum about 15cm in diameter, which rotated about once a second. Fixed on the drum was a raised spiral. This spiral ran from one end of the drum to the other and made one full turn from end to end.
The recording paper was drawn slowly over the drum which rotated under it. Thus the spiral moved regularly from one side of the recording paper to the other. (left to right)
Held just above and stretched across the paper was a length of typewriter ribbon. Above the ribbon a bar was suspended. This bar was mechanically connected to a relay.
When the relay was pulsed the bar was rapped against the ribbon, which produced a mark on the paper which coincided with where the raised spiral was at that instant.
The relay was pulsed by the output of the receiver which divided its time between the three traces. (still with me?)
The pulses were obtained from a photo electric cell, light source, combination. This combination rotated in synchronism with the drum.
The light source was interrupted every revolution by a meter needle. The meter needle's position depended on the particular radiosonde parameter being received at the time.
So as the receiver divided it's time between parameters and a tapping pulse was generated each revolution by the meter needle, each parameter was traced separately on the recording paper.
I have included this description to indicate just what a mechanical marvel the Cycloray recorder was.
It was an ingenious system which worked reasonably well but a lot of things could go wrong and often did. Music to my ears was the regular tapping sound as the relay pulsed. If the tapping bar worked it meant the rest of the system worked. Any missed taps meant trouble. It got to the stage that I reckoned I could hear missed taps from anywhere on the Island.
To my mind, when a radiosonde flight was in progress, it was great if the only sounds were the regular tapping of the tapping bar and the good clear regularly-changing drone of the radiosonde monitor as it cycled through its data transmissions. That and the sound of paper being shuffled as the Met observers plotted the information as it arrived.
Definitely bad was to note missed taps, which would usually be followed by the exasperated tones of the observer. "This thing's missing taps again!"
I wonder what happened to the old cycloray, I hope it ended up in a museum somewhere. The incoming tech brought a new Brown recorder with him which did away with all the above problems.