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Aussat link highlights 1987 Jamboree of the Air Amateurs make historic radio link via satellite This year's Jamboree of the Air had a special highlight. Amateur radio operators in Sydney were able to talk to those in Perth via their 2-metre repeaters. This would normally be impossible but Aussat supplied a link via satellite to enable this historic link-up. By ROSS TESTER, VK2KRT Amateur radio operators in Sydney and Perth couldn't believe their ears. VK6 stations by the score were coming up on Sydney's Manly-Warringah Repeater VK2RMB while over in Perth VK2's were thronging in on their repeater VK6RTH. For a while, most operators weren't too sure what was happening. "What an Opening!" was heard more than once. ("Openings" are changes in the ionosphere which permit long distance communication). Openings have occurred, very rarely, to permit Sydney stations to communicate with New Zealand, Southern Queensland, Victoria, even South Australia. But an opening to Perth would be considered an event to eclipse the bicentennial itself! Incidentally , the Australian QSL card from Ross Tester, VK2KRT for the first ever hand-held 2-metre contact across Australia via satellite. Ross was at Narraheen Beach on the east coast. 40 SILICON CHIP record for two metres is held between VK4ZSH (Queensland) and JA7OXL (Japan) - a distance of 6617km. Back to Australia: as more and more operators joined the "pile-up" on two metres, the truth began to emerge. And the truth was even more of an event than a crosscountry opening. The link between Sydney and Perth was actually occuring over a distance of some 72,000km - via one of the Aussat satellites! Very quietly (until amateurs found out about it, that is) amateur communications history was being made in Australia and, probably, the world. It ' s not the first time that amateur radio has gone into space. Amateurs have, on quite a few occasions, launched their own satellite repeaters as "piggy back" payloads on commercial launches. And amateurs the world over remember the Space Shuttle amateur, Dr Owen Garriot, who took along his radio a couple of years back. To the best of our knowledge though, the linking of VKZRMB and VK6RTH via a commercial communications satellite is a world first. And because of the outstanding success of the operation, it certainly won't be the last. The link was first made for a short period on Monday, October 12th. It was made again on Tuesday 13th and left active for "testing" almost continuously until the JOT A weekend of 17th and 18th October. The link was finally removed early on Monday 19th. How it happened Several of the staff at the Aussat Earth Station at Belrose (Sydney) were musing over their morning "cuppa" about JOTA: the international Scout, Guide, Brownie and Venturer's "Jamboree of the Air". JOTA is held each year, on every continent, and Scouts talk to other Scouts both within their own countries and around the world. The various scouting associations have their own amateur licences but thousands of non-Scouting amateurs lend both their stations and their time to assist the Scouts for the two days of JOT A. As you might expect, all the amateur bands are pretty active during the JOT A weekend. There are many more Scouts than stations. Given the vagaries of amateur radio, conditions cannot be guaranteed and communication is sometimes difficult. Naturally, international contacts are considered the "prize" of JOT A but equally important are the contacts between scouts in various parts of the country. Local area repeaters are also in heavy demand but their range is limited to around 100km or so. The Aussat staff had a brainwave: why not see if a Sydney repeater could be linked to the Aussat Earth Station and fed via satellite to another repeater on the other side of Australia? Scouts would get contacts previously only possible on HF and then only with great difficulty. Like many brainwaves, execution proved to be a little more difficult. But with credit to Aussat staff in Sydney and Perth, officials of the radio clubs, the Wireless Institute of Australia (WIA) and the JOT A organisers of the Scouting Association, it started happening. PERTH WESTERN AUSTRALIA ZONE 29 CONFIRM QSL S ,r - DATE GMT MHZ 2 WAY AST 73s HAAI Ql-lc s PSE L ._. Arthur J. Brean 28 Bennion St., Trigg. W.A. 602q Western Australia. From the other side of the continent - the QSL card from Arthur Brean, VK6SY, Trigg, Western Australia. Arthur was just two hundred metres from the Indian Ocean. being line-of-sight to the Belrose Earth Station at just a few hundred metres away across a gully and a couple of ridges. The Manly Warringah Radio Society agreed to have their repeater " hijacked " for the weekend of JOTA. The West Australian Repeater Group were equally as enthusiastic about having their Channel 4 repeater at Herne Hill linked to the Aussat Earth Station at Lockridge in Perth. Then came the Department of Communications. Of course, Aussat holds licences for its satellite services but could they link to the Amateur Service? Finally, approval came through from a new Department: DOC had been merged with the Department of Transport in the meantime and DOT AC finally gave the OK. In the middle of all this negotiation, of course, came the launch of Aussat 3 in August. Needless to say, this was considered a pretty significant event at Aussat, and staff time to work on the "freebie" project was simply non-existent. Then came the logistics First and foremost were the "powers that be" at Aussat. Could they justify giving free satellite time in what is, after all, an extremely expensive business? "Yes. It's great public relations!" Second came the question to the Scouting Association: did they really want such a link? Did they what! And of course, the 2-metre amateur repeaters to be used: the Manly-Warringah repeater (VK2RMB) was a natural choice, Aussats 1 and 2 were launched aboard US Space Shuttles. The Shuttle should go into space again about the middle of next year. DECEMBER1987 41 After the extremely successful launch of Aussat 3 on top of an Ariane rocket from French Guyana, organiser Laurence Adney (VK2ZLA) at Belrose Earth Station was able to devote some time to the JOT A project. Technical Details With the project given official go ahead on all counts, the "nuts and bolts" had to be organised. First was the link from the repeater to Aussat. That was the easy part signal was taken straight off air from the respective repeaters, via a normal 2-metre transceiver (a Yaesu FT230R, loaned for the event by David Folkes, VK2XDF, was used at Belrose.) In perhaps one of the best examples of a "belt and braces" approach, an 8-element Yagi antenna was aimed direct at the Terrey Hills repeater from Aussat Belrose. There was no way it wasn't going to get signal! VK2ZLA also brought in his own 2-metre transceiver to use as a system monitor (talk about carrying coals to Newcastle!) - with one of the most expensive ground planes for his magna-base antenna ever seen (he "borrowed" one of the access doors from a multi-million dollar satellite transponder controller. Yes, it worked very well, thank you). Technical development at Aussat Satellite Frequencies Sydney Downlink .. Uplink .. . . . . Perth Downlink .. Uplink . .. ... 12,575.2825MHz 14,323.2825MHz 12,575.3725MHz 14,325.3725MHz 2-metre Frequencies Sydney, VK2RMB Transmit ... .. .. ... 146.275MHz Receive .... ....... 146.875MHz Dural, VK2WI Transmit .... .. ... ... 146.40MHz Receive ............. 147.00MHz Perth, VK6RTH Transmit ........... . 146.20MHz Receive ......... .... 146.80MHz 42 SILICON CHIP . .. ' ,. , . ~ . , Aussat 1 pictured in the Shuttle cargo bay prior to deployment in space. Australia's third domestic satellite, Aussat 3, was successfully launched by Ariane rocket last August. was carried out by another Aussat staff member, Bruce Boardman (VK2XDF). Bruce designed the interface unit which triggered from the "busy" indicator on the Yaesu FT-230 transceiver to switch the Aussat transponder control from transmit to receive. Unlike the repeaters, the Aussat transponder is designed to operate in a "VOX" mode - the controller had to be hard-wired to achieve what effectively became carrier control. Equipment at the Lockridge end was supplied and fitted by Will McGhie, VK6UU, with technical support by John Sherman and the Aussat staff. One unexpected problem which needed solving was the fact that, when installed, each repeater could be triggered by the " tail" of the other, effectively locking up the system. This was simply solved by including a one second delay in the triggering of the Perth repeater. "Aha!" amateurs all over Sydney are saying. " That's why we kept losing the first word or so if Perth amateurs were too quick on the PTT!" And because of the one second delay at the Perth end, amateurs in Sydney were able to tie up the system completely by not allowing the one second to tail out. "Aha!" amateurs in Perth a re saying. "That's why we couldn't get a word in edgeways when those VK2's were coming through loud and clear! " Of course, there were a few problems with the link itself. One occurred on Friday night when a carrier locked the Perth repeater on. While full remote control was built into the Perth end, Aussat Sydney simply disconnected the link while the Perth boys D-F'd the offender (ie, they used a direction-finder to locate the source of the carrier l. Apart from these minor aberrations though, the link was incredibly successful. Not just for JOT A but for the hundreds of Sydney and Perth amateurs who contacted each other during the unofficial " testing" period on Wednesday, Thursday and Friday. A measure of the success can be gleaned from the hour-meter attached to VK2RMB. On a repeater that would be lucky to see twenty hours use in a week, a single-48 hour period (Thursday/Friday) saw a staggering 38 of hours use! Amateurs on both sides of the continent were impressed, to say the least. Thousands of contacts were made - some very brief, just to make the log for QSL purposes; others much longer. Old friends, even long-lost members of families were re-united thanks to Aussat. Even some records are being claimed: Arthur Brean VK6SY and Ross Tester VK2KRT (the author) are claiming the first 2-metre handheld contact across Australia. VK6SY was just a couple of hundred metres from the Indian Ocean and VK2KRT was at Narrabeen Beach, on the Pacific Ocean. So they cheated - just a bit! One of the best stories to come out was from Michelle, VK2FJJ, who made a chance contact with another operator in Perth, only to find that the Perth amateur lived just a couple of doors from her son. Guess who saved some phone calls! Pity the poor pasties with those thousands of QSL cards. Australia Post will be thanking Aussat all the way to the bank! Satellite details This report would not be complete without details of the "bird" - if only to correct the misinformation being broadcast at the time about the link. The spacecraft used was Aussat 1, the first of the three Aussat satellites launched on August 27, scort 1985 by the US Space Shuttle, Discovery. Aussat 1 is in geostationary orbit some 36,000km above the equator at 160 degrees E. Aussat 1, like the other two Aussats, has 15 operational transponders, 4 x 30 watts and 11 x 12 watts. It is 2.2m in diameter, 6.6m high and weighs approximately 650kg. Expected service life of Aussat 1 is seven years. (The life of the satellite is basically the amount of hydrazine fuel left on board after launch. Satellites drift out of orbit and must be moved back - when the fuel runs out, that's it). All three satellites are controlled by the Belrose Earth Station but can also be controlled from Perth. The Sydney/Perth link used Transponder 13 (maximum output 12 watts). The Aussat earth stations are capable of immense power around 2000 watts - should the situation require it. On the Kuband, from 12 to 14 Gigahertz, rain and cloud can cause considerable signal loss and the power is adjusted accordingly if these condi- AL tions occur. On the JOT A link though such power was not required. In fact, the travelling wave tube amplifiers were barely idling. And next year? Because of the huge success of the link this year, Aussat may look kindly to doing a similar link next year. Similar, but not necessarily the same. Consideration is also being given to using Aussat's South West Pacific Beam to link Sydney and/or Perth to New Zealand (or perhaps even some of the island nations of the region such as Tonga, Fiji, Tahiti and so on). Linking to a foreign country opens up a whole new set of problems, both from a logistic point of view (do they have the infrastructure necessary?) and, of course, legally. Regardless of whether the Aussat link is ever made again, the JOT A stations and the thousands of amateurs who made use of it this time were grateful for the effort made by Aussat staff in allowing them to be a part of this small piece of communications history. ~ PERFOR C Reliable Test Instruments for the Electronics Enthusiast Pocket Size Robust Handhelds LCR Meter EDM-70H • 3½ digits LCD • 6 functions • DC V • AC V DC A • Ohms • Transistor Test • Diode Check $59 I~~~ V A n -+1-c EDM-728 • 3½ digits LCD • 8 functions • DC V • AC V • DC A • AC A • Ohms • Diode Check • Buzzer ••l) $82 I~~~ lll EDM-1111A EDM-1105A • • • • • 3½ digits LCD • 7 functions 0.8% Basic Accuracy • DC V AC V • DC A • AC A Ohms • Transistor Test Diode Check • Buzzer $96 ~1~ 1 DIVISION OF EHONA ENTERPRISES PTY LTD • • • • • • 3½ digits LCD • 9 functions 0.8% Basic Accuracy • DC V AC V • DC A • AC A Ohms • Transister Test Diode Check • Buzzer CAPACITANCE $113 ELC-120 • 3 ½ digits LCD • 1% Basic Accuracy • C: 200pF to 200uF (0.1 pF) • L: 2mH to 200H (1 uH) • 20Mo (0.010) ~1~ 1 $243 SALES SHOWROOM 86 Parramatta Road Phone (02) 519 3933 Camperdown 2050 FAX (02) 550 1378 ~1~ 1 , INTERSTATE DISTRIBUTORS VIC OLD WA Radio Parts Group, Melbourne. 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