June 2008 - AMSAT-BB - mailman.amsat.org

Spanish cubesat
by rct＠uvigo.es 17 Jun '08

17 Jun '08

Dear colleagues, The Telecommunication School at Vigo University, Spain, is developing a cubesat that will be launched by ESA. It will transmit in amateur bands, and the University radioclub (EA1RCT) is collaborating in the project. The design is not yet closed and we can send proposals to the development team. The radioclub is willing to hear ideas from the amateur radio comunity: we would like to have a short list ready by next Thursday, June 26, so any proposal we receive before then will be carefully read. The satellite will be small and lightweight as you know, and it will run on a short electrical budget. Moreover, the time schedule is very tight. One of the main objectives is to test SDR systems in space (not necessarily in amateur bands). Neither the bands, power o full-duplex capability have been established. It could eventually end up with just a telemetry beacon. We would like to hear your opinions about what the amateur radio community would prefer to carry on board, in these three scenarios: · full-duplex communication capability (linear transponder, fm rep, etc) · half-duplex systems (digipeater?) · beacon modes (afsk, psk, cw) Best regards, EA1RCT RadioClub Telecomunicaciones Vigo http://lostrego.uvigo.es

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AO7 status
by John Geiger 17 Jun '08

17 Jun '08

I have been out of the satellite game for awhile, but now am back, after getting the 70cm antenna back up and a second radio to do full duplex with. What is the current status of AO7? The AMSAT page says "non-operational" but I seem to have seen some emails recently that might suggest otherwise. If it is operational, is it always in Mode B now? 73s John AA5JG (ex: W5TD, NE0P) 6M WAS #1275, 6m VUCC #1260 2m VUCC #615, Satellite VUCC #129

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Re: Spanish cubesat
by Sam KC2LRC 17 Jun '08

17 Jun '08

First off all, thank you for giving us the opportunity to toss out our ideas for the satellite! Since the power budget of the cubesat will be very limited, I feel an FM repeater is the way to go. Nihon University's SEEDS II cubesat shows that it is possible to run an FM transmitter for at least a significant time within the power budget of a single unit cubesat, and its signal is very easily received even with simple handheld 435MHz beams. At the same time SO-50, with its 250mW transmitter, shows that such a small transmitter power can still be reliably and clearly received. The FM transmitter involved in this design could be used for other purposes as well. It could be used for SSTV transmissions, AFSK telemetry, or even a digitalker. So if the satelite also has scientific payloads, the same transmitter could first be used to downlink payload data, and then could be switched to repeater mode when the experiments are complete. A BPSK transmitter could also be used but this would limit the audience - there are many hams out there, like me, who don't own all mode VHF/UHF gear. 73, Sam KC2LRC - FN13

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Satellites 101
by Tim Tuck 17 Jun '08

17 Jun '08

Hi all, I've been asked to give a "101" talk about satellites at my local radio club and before I go reinventing the wheel I was wondering if anyone has a slide deck in pdf or pps I could use ? thanks Tim -- VK2XTT :: QF56if :: BMARC :: WIA :: AMSAT =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- Scanned with Copfilter Version 0.84beta3a (ProxSMTP 1.6) AntiSpam: SpamAssassin 3.2.3 AntiVirus: ClamAV 0.91.2/7484 - Mon Jun 16 06:11:46 2008 by Markus Madlener @ http://www.copfilter.org

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Re: LEO
by John W Lee 17 Jun '08

17 Jun '08

AMEN ! On Tue, 17 Jun 2008 17:11:09 -0400 "Jim Danehy" <jdanehy(a)cinci.rr.com> writes: > I am perplexed why some have to be critical of another person's > interest. I am a QRQ CW operator. If you do not like CW that is OK. > I do. We will probably not work on that mode if you don't like it. I > cut my teeth on Oscar 6 and dropped out of satellites in about 1982. > I have not yet tried an FM bird. I am working to get back on LEOs > on CW. I will probably do SSB too. I hope to be on soon. > > There is a saying that if it isn't CW it is just CB. I look forward > to HEO but until then it is LEO. > > Jim W9VNE > Cincinnati, Ohio > EM 79 > _______________________________________________ > Sent via AMSAT-BB(a)amsat.org. Opinions expressed are those of the > author. > Not an AMSAT-NA member? Join now to support the amateur satellite > program! > Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb > > ____________________________________________________________ Sweepstakes!!! Enter for your chance to WIN a summer spa getaway! http://thirdpartyoffers.juno.com/TGL2141/fc/JKFkuJi7UjkWoH7XEreOpxKX0rnHJmj…

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FM satellites versus linear HEOs
by OZ1MY 17 Jun '08

17 Jun '08

Hi all, I think the 14 year old radio amateur got it right :-) The are many aspects to the hobby as he points out. Some of us like one thing others want something else - but I think most of us want both linear transponders on HEO satellites and LEO satellites with FM transponders or linear transponders. As far as I can see, most large AMSAT organizations (DL and NA) are building and hope to launch HEO satellites these days. Small AMSAT organizations may still want to build and launch LEOs perhaps in cooperation with universities in their home country. I can not to see the problem. If the 2 meter band is too crowded and the same in the 70 cm band let us move to higher frequencies. These days with PC control of the transceivers it should not be a large problem to use these higher frequencies even with LEO satellites. 73 OZ1MY Ib

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LEO
by Jim Danehy 17 Jun '08

17 Jun '08

I am perplexed why some have to be critical of another person's interest. I am a QRQ CW operator. If you do not like CW that is OK. I do. We will probably not work on that mode if you don't like it. I cut my teeth on Oscar 6 and dropped out of satellites in about 1982. I have not yet tried an FM bird. I am working to get back on LEOs on CW. I will probably do SSB too. I hope to be on soon. There is a saying that if it isn't CW it is just CB. I look forward to HEO but until then it is LEO. Jim W9VNE Cincinnati, Ohio EM 79

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Re: Spanish cubesat
by Trevor 17 Jun '08

17 Jun '08

First of all my thanks to RadioClub Telecomunicaciones Vigo for inviting suggestions for an Amateur Radio payload for the Spanish cubesat. Personally I'd be keen to see a 435/145 MHz linear transponder for Amateur SSB/CW operation. Clearly the satellite power budget would present a major constraint but perhaps a 30 kHz bandwidth linear transponder running about 100 milliwatts PEP output would be feasable ? Maybe such a transponder could make use of the Software Defined Radio (SDR) system already planned for the cubesat. I wish you every success with whatever you decide to fly on the cubesat. 73 Trevor M5AKA __________________________________________________________ Sent from Yahoo! Mail. A Smarter Email http://uk.docs.yahoo.com/nowyoucan.html

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Re: Frequency Co-ordination.
by Wayne Estes 17 Jun '08

17 Jun '08

Andrew Koenig KE5GDB wrote: The FM birds are all that I have access to at the moment. I personally don't mind the fast paced callsign/grid exchange, but that doesn't seem to float some people's boat. I do just fine. My income is very limited, since being 14 years old doesn't really pay that much. I cannot afford some of these fancy all mode rigs that can even make you a cup of coffee. All I've got in my inventory is several FM UHF and VHF rigs that get me on the FM birds. Amateur Radio is a wide spectrum. There's lots of different things that can take place in different ways. Some rely on the ionosphere to get their contact, and other's rely on the pass predictions. It's not easy to float everybody's boat, but most of the time we seem to get along OK. Wayne W9AE replies: You posess wisdom FAR beyond your age. You will no doubt have a bright future, and I hope that future includes amateur satellites. 73, Wayne Estes W9AE Oakland, Oregon, USA, CN83ik

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Frequency Co-ordination.
by John Hackett 17 Jun '08

17 Jun '08

I believe this mail ought to be forwarded to *ALL* amateur radio satellite organisations. We've - (GM1SXX & LA2QAA) - said it often enough in the last 10 years but if we persist, somebody just might finally get the message. Commander John Brannegan G4IHJ made us aware of the problem in 1994 ... so far, to the best of my knowledge, it's been totally ignored. Please *DO* note the last paragraph. 73 John. <la2qaa(a)amsat.org> To: eu-amsat(a)yahoogroups.com From: allan_gm1sxx(a)hotmail.com Date: Mon, 16 Jun 2008 08:33:45 +0000 Subject: [eu-amsat] The IARU, Satellite Frequency Co-ordination and the CUBESAT Bands. Hi Folks. Having read through the material pointed to by Trevor, it seems the case that unco-ordinated satellites and the proliferation of University CUBESATs on 2M and 70Cms (the prime bands for linear transponder birds), are indeed a problem that is not being addressed, or about to be addressed, any time soon. Sure, there will be talk about addressing the problem, but that's all. As best I can understand, the IARU believes it is an issue for local (National) radio societies. With no-one 'steering the ship', as it were, it's hardly any wonder it ran aground a long time ago. Complaining to your national radio society is unlikely to carry much clout for a satellite builder at the other end of the world. In short, it's a free-for-all. It's not a new problem either, see Altruistic radio amateurs (1994) ftp://ftp.amsat.org/amsat/articles/satgen/sgen268.txt John GM4IHJ noted this growing problem 14 *years* ago, and yet nobody seems to care. Perhaps we really do get what we deserve. It's likely that AMSAT will be a forgotten organisation once the two most useful band segments we are allowed are littered with 'me-too' satellites. Can you imagine a future scenario....not too far in the future. 'Linear transponders on 2m & 70Cms?'.... don't be silly, those are the Cubesat bands :-). 73 Al. GM1SXX __._,_.___ Messages in this topic (1) Reply (via web post) | Start a new topic Messages | Files | Photos | Links | Database | Polls | Members | Calendar MARKETPLACE Blockbuster is giving away a free trial of Blockbuster Total Access to smart movie lovers like you. Change settings via the Web (Yahoo! ID required) Change settings via email: Switch delivery to Daily Digest | Switch format to Traditional Visit Your Group | Yahoo! Groups Terms of Use | Unsubscribe Recent Activity 7 New Files Visit Your Group Real Food Group Share recipes and favorite meals w/ Real Food lovers. Dog Groups on Yahoo! Groups Share pictures & stories about dogs. Moderator Central An online resource for moderators of Yahoo! Groups. . __,_._,___

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