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On Wed, 5 Jan 2005 12:15:33 -0800, "Joel Kolstad"
wrote: I'm curious... how is this down? Hi Joel, This may not answer your question, but you can always contact the author of: To: "Richard Clark" Subject: The Dish From: "Gary Peach" Date: Thu, 12 Apr 2001 08:42:21 +0100 Subject: The Dish Something that I've wanted to ask, and it relates to the subject line. "The Dish" is a movie about a NASA communications link in Australia. I remember your file you sent me about calibrating S-Meters (something I still consider and ruminate on, it was excellent writing). However, that file is on another machine and my recollection insists that you might be a participant in the story that is being told in this movie. I did go up to Parkes before the Mission. Parkes is 50Hz and the Resdel Receivers were 60 Hz. Thus a standards converter was necessary. The Yanks supplied a fancy crystal controlled box of tricks about a metre cube. This unit was distinctly unreliable and overly complex for the task which would be more reliably done by having a 50 Hz motor connected to a generator through a belt drive system with pulleys whose diameter were in the ratio 5/6 . This type of device could be duplicated easily so as to have a stand by unit and the technology within the skills of the local electrician to fix. More in a moment about what eventually happened. You may wonder about this all. "The Dish" has just been released, so you may be unaware of the plot line (which I cut and paste from the net): Synopsis: On July 20, 1969, six hundred million people sat glued to their televisions for man's first steps on the moon. It is an image permanently ingrained in our collective consciousness, but one that almost didn't make it to the airwaves. Based on true-life events, The Dish is a waggish homage to the small-town heroes responsible for a historically almost calamitous blunder. Outside the small, sleepy town of Parkes, a team of laid-back astro-technicians led by project director Cliff Buxton and NASA agent Al Burnett ready the Southern Hemisphere's largest satellite dish to transmit the historic broadcast. But amidst a swirling media frenzy and overly effusive civic pride, things start to go awry; the team has lost the signal and must scramble to find the astronauts before NASA discovers their grievous error.. And you thought Sydney 2000 was the first time we showed the world! I sent this on to the two guys detached from Tidbinbilla to Parkes for the actual Mission. Both close friends. The man in charge was so upset that he refuses to discuss the issue. I know him to be a fine Technician, and the other guy is similarly trained. Both EX RAF Radio and RADAR trades, so not only good technically, (they really trained us in those days), (Now they do not train the technical people further than board jockeys and the training facility at RAF Cosford is run as a private college and personnel may take courses to any level including degree level. Private persons may attend the college and many overseas persons now attend, (As did foreign military personnel attend or training facilities back in the 50s) The guy in charge had completed a number of years as a senior instructor with the RAF. When I forwarded this bit of nonsense to him he was indignant about it and said that what he'd heard of the film had made him sick and he refused to see it. Some how or other they had got the power monster going buy substituting transistors of a beefier type in the power output stages. As far as they have said it performed well. Of course Parkes did not have a MASER so their system temperatures could not approach those that we had at Tidbinbilla, we were therefore Prime at Tidbinbilla and Parkes despite its much larger Dish at that time it was only back up. The famous moon landing was handled at Tidbinbilla because of our superior technical performance. superior for two main reasons, 1. we had a MASER which permitted us a system temperature of 40°K and 2. I had tuned the waveguide distribution system to very fine standards such that we could switch between two high power transmitter (20 kW) in less than 3 seconds. In fact I used to do it at the touch of a button The huge waveguide switches have to have a finite time to change over as the stored mechanical energy in the rotors is so great that if the time taken to switch is reduced (without my modification) the switches after a few operations would tear themselves to pieces. If you take a butcher's at my Web page you will see a picture of me working on my home brew Waveguide reflectometer that permitted me to tune the wave guide over the entire bandwidth of interest (2,110 - 2,295 MHz) The lower frequency is the up link and the higher is the downlink. Of course diplexers and filters are used as the signal is a phase modulated carrier therefore CW full power at all times. It is not a practical measure to work simplex to a spacecraft that might be changing attitude quite violently and at a distance from Earth such that even at the speed of light the signal takes 20 Minutes to do the round trip when out at Mars distances. Even to the moon a 3 sec delay is incurred. Anyway enough of my digression "The Dish" is a pure fiction, and both of my friends consider it an insult. As I was at Tidbinbilla and apart from some sabotage three days before launch which made the front page of Newspapers around the world we performed to specification without a hitch. The power supply problem was the three phase input to the power supply for one of the klystrons. The grub screws to all three cables in the circuit breaker bringing in the 60 Hz power that we generated on site with huge mega watt Caterpillar generators. The cable connections arced and vaporised the circuit breaker and the arc continued from the remaining wires and the intense heat melted a hole about 18" diameter through the 3/16" steel casing. Teams of our volunteer technicians worked night and day in shifts non stop to rebuild the very complex power supply. The vaporised circuit breaker had coated the surfaces of all components with a carbon layer. With 45 kV plus floating around at several amps that is not a good situation. However the work was completed on time and I was able to hear Neil Armstrong use my words, "One small step...", a few days later. PS Sorry for the delay, I bin a bit under the weather and I wanted my friends reactions before I made any comment, as Apart from the Power converter week up there I really had nothing to do with the operational side of Parkes. I did meet the famous astronomer Bart Bok. When we arrived there was a doubtful looking character up in the dish surface dressed in shorts and an open brown shop coat. In his hand a bucket of tar and in the other a scrubby little brush. He was up doing some repairs. As our car pulled alongside the Dish he came down and I taking him for a labourer asked him where we could find the person in charge. He was a very kid and approachable person. Later he took me on a guided tour of the structure and I was most impressed. That was a goodish week up in Parkes and the locals were very hospitable. I guess for much of the week I was inebriated in the evenings. And mainly entertained in private homes of the local aristorinocracy. But that is quite another story ![]() -- 73 de Gary7SLL NEWBURY IO91ij RAFARS 2757 73's Richard Clark, KB7QHC |
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