July 2007 - AMSAT-BB - mailman.amsat.org

Call for Papers--2007 ARRL/TAPR Digital Communications Conference
by Ford, Steve, WB8IMY 16 Jul '12

16 Jul '12

Technical papers are solicited for presentation at the 26th Annual ARRL and TAPR Digital Communications Conference to be held September 28-30, 2007 in Hartford, Connecticut. These papers will also be published in the Conference Proceedings (you do NOT need to attend the conference to have your paper included in the Proceedings). The submission deadline is July 31, 2007. Please send papers to: Maty Weinberg ARRL 225 Main St Newington, CT 06111 or you can make your submission via e-mail to: maty(a)arrl.org Papers will be published exactly as submitted and authors will retain all rights. 73 . . . Steve, WB8IMY ARRL

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FS: Kenwood TS-790A + IFD board + TNC31S
by Francisco Costa, CT1EAT 19 Jan '08

19 Jan '08

Dear AMSAT friends My pacsat station is for sale: Kenwood TS-790A 144/432/1200 MHz transciever ============================================ with the following extras: * UT-10 1200 MHz module * Symek IFD-B board (for speed up to 76000 bd) and mods: * extended rx (on 3 bands) * 9600 baud tx/rx * 100ms mute disabled * IFD-B board (38400 baud rx) plus: * Hand microphone * DC cable * Instruction Manual (in english) include schematics * External Control Instruction Manual (in english) * Modifications documentation (in english) All mods were performed by me and no holes were done. This equipment was bought new (1997), and until now there was not a single problem! It was kept on a non smoking environment. Cosmetic is a 8/10 (one minor dent, sort of paint bubble and 4 rotator control box feet "stain", all on top cover) Unfortunatly I don't have the original box anymore. Sorry TNC Symek TNC31S ================ * Tx 9600/Rx 38400 baud card * 128kb RAM * 512kb Flash-EPROM * English mailbox * Kiss autostart including: * RS232 cable plus adapter (DB9) * DC cable * Diskette with software * Original Manuals (english and german) This TNC was bought new (2000), and was used on UO-36 and Tiungsat-1 with great sucess. I did't use it since a long time ago, but I belive it's 100% operational. Cosmetic is 9/10. I will only sale the 2 items together. Price: 1500 Euro Buyer pays shipping. Payment methods: Euro countries: Bank money transfer only! Elsewhere: Western Union or PayPal. Photos: please visit http://ct1eatsale.no.sapo.pt/ Thanks for your attention. See you on P3E or Eagle. 73 F.Costa, CT1EAT www.qsl.net/ct1eat

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Re: VO-52
by Andrew Glasbrenner 01 Sep '07

01 Sep '07

Excellent advice Tom. Let me add a few things if you don't mind. If you cannot implement full doppler computer tuning, the next best practice is to tune the higher frequency, in this case the uplink. Use full duplex and the minimum power required. VO-52 is quite sensitive and overloads easily; expect this to be the norm on FD. Don't forget AO-7. It could be in either Mode U/V (aka Mode B) or Mode V/A (aka Mode A). FO-29 may also be back in time for FD, we just don't know. I expect the majority of points to be made on the transponder satellites; please observe the one QSO per FM repeater rule (1 via AO-27 and SO-50, and 1 each via the L/U and V/U repeaters on AO-51). For the true diehard satellite operator there is AO-16! The 1200 baud BPSK downlink is easily decoded with MixW soundcard software, and the uplink requires Manchester FSK at 1200 baud. This is the tough part. QSOs can be completed via digipeating through the satellite, but the BBS is non-operative. GO-32 is a good bet too if the BBS is up and running. Good Luck on Field Day! 73, Drew KO4MA AMSAT-NA VP Operations -----Original Message----- >From: Thomas McDaniel <tmcdanielsprint(a)earthlink.net> >Sent: Jun 3, 2007 8:44 PM >To: kc6uqh <kc6uqh(a)cox.net>, AMSAT-BB <amsat-bb(a)amsat.org> >Subject: [amsat-bb] Re: VO-52 > >Hi Art, > >I don't know of a site for this satellite with operating information. >However, this is what used to be called a Mode B satellite -- 70 CM LSB >uplink and 2 Mtrs USB downlink with a reverse transponder. Because the >satellite is in a very low orbit I highly recommend a computer controlled >transceiver (FT-847, IC-910, TS-2000 or etc.) and SatPC32 (you can get a >free download to test with from Eric's web site: >http://www.dk1tb.de/indexeng.htm ). We generally use the "one true rule," >that is computer control both up and down link to stay in one spot on the >transponder. > >For antennas, we will be using RH circular beams and automatic tracking, but >I expect you could use an Arrow type antenna with someone manually pointing >in the general direction -- turnstiles, egg beaters or other omnis may work >ok but I haven't tried them. > >Finally, practice before Field Day to "work out the bugs" is highly >recommended. :-) > >73 Tom n0ntx >AMSAT Area Coordinator >Colorado Springs, CO > >----- Original Message ----- >From: "kc6uqh" <kc6uqh(a)cox.net> >To: "AMSAT-BB" <amsat-bb(a)amsat.org> >Sent: Sunday, June 03, 2007 12:45 PM >Subject: [amsat-bb] VO-52 > > >>I am considering using VO-52 for Field Day. Could anyone direct me to a >>site with operating information, not bragg tapes on this satellite. I >>found the Indian site but I could not find any real technical information. >>The AMSAT frequency guide mentions both Indain and Dutch transponders shows >>only one set of frequencies and no suggestion as to USB tX or RX does >>indicate U TX and V receive. Uses turnstile antennas, Rh or Lh Circular? >> >> Thanks, >> Art, >> KC6UQH >> _______________________________________________ >> 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 >> >> >> -- >> No virus found in this incoming message. >> Checked by AVG Free Edition. >> Version: 7.5.472 / Virus Database: 269.8.7/830 - Release Date: 6/3/2007 >> 12:47 PM >> >> > >_______________________________________________ >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

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AO-7 report.
by John Hackett 06 Aug '07

06 Aug '07

A study of the AO-7 eclipse charts for the last 3 years shows a progression toward non-elipse orbits in late 2007 - 2008. In effect, this means that AO-7 in all probability will not change mode unless anything untoward happens. It also means that we appear to have a permanent mode-B LEO linear transponder for the forseeable future ... providing operators follow the recommended operating proceedure. Please *do* decrease your power as the satellite approaches TCA to avaoid FM'ing. This not only helps the satellite, it helps the other operators in the passband. Don't be fooled by propagation anomolies. The mode-B transponder is working well and will continue to do so providing the alligators go and play somewhere else. Under normal circumstances you do NOT !! need a lot of power. Please use only the necessary to maintain adequate communications. If you can't copy people adequately, you should improve your receiving capabilities rather than increasing your uplink power ... remember, aluminium is cheap and it's a lot more user friendly to everyone concerned .... with perhaps the exception of your neighbours. For all intents and purposes, AO-7 is a QRP satellite. Please treat it as such. 73 John. <la2qaa(a)amsat.org>

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ARRL dual moxon turnstyle project questions
by Scott Wilson 05 Aug '07

05 Aug '07

I'm working on building the ARRL dual moxon antennas, but the article isn't very detailed where I'd like it to be and a little over detailed in some places I wish it weren't. If you want to look, this is the URL (http://www.arrl.org/members-only/tis/info/pdf/0108038.pdf) 1. What are acceptable ways to terminate the paralled 75 ohm matching sections? I'm thinking now I'll just terminate them to a couple of ring terminals attached to the mast rather than terminating each one with a bnc and teeing them. 2. How do I feed the 70cm and 2m with the same feedline? should I just tee a 50 ohm line to two equal length 50 ohm sections? 3. This is more of a comment... I'm wagering the uhf version doesn't work at all... measurements are given to the hundreth of an inch - and then you solder a big ring lug to the end of it! 4. Are there any other good techniques for setting the distance between the reflector and driver besides heat shrink? The 70cm antenna is using #14 galvanized wire, and I can't think of anything small enough to hold them in place well. I found that the 3/16 rod for the 2m moxon will work great with 1/4" nylon tubing. Thanks for any feedback - I'll probably have more questions.. I'm sitting here with a half-made 70cm turnstyle, and am about to start on the 2m version. Whew - I'm beginning to think that a $1000 investment in rotators and antennae isn't such a bad idea after all! Scott Wilson NW2S

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Questions for the 2007 BoD Candidates
by Dave hartzell 02 Aug '07

02 Aug '07

I would like to post a set of questions for the AMSAT BoD candidates, as Stefan (VE4NSA) did almost exactly a year ago. It will certainly help me select the best candidates. Since I don't think you need to go so far as to do a YouTube video, please help us understand your positions and the value you would bring (or have brought) to AMSAT. Thanks to the candidates for your time and for running! Without volunteers like you, AMSAT would not be! Questions: * How are you planning to advance AMSAT as a professional organization in terms of management, membership service and transparency? * How often have you been using the existing satellites (e.g. AO-51) in the last year. * What do you consider as the greatest asset AMSAT has? * What do you consider is AMSAT's greatest weakness and how will you address it? * What are you planning to do to ensure a healthy, stable future for AMSAT? Thanks and 73! Dave N0TGD

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AMSAT IRC Channel on Freenode
by Eric H Christensen 01 Aug '07

01 Aug '07

A friend of mine and I were chatting on freenode IRC and was wondering if there was an AMSAT room. When we checked there was not so we unofficially established one to see how much interest there would be. This could be a low-bandwidth back channel that AMSATers worldwide could join into and chat in real time about satellites, during passes get feedback, or people could come to get assistance when they are having problems. I know the IRC channels are being used for the same reason for other projects, why not AMSAT? If you already have an IRC client come join us at irc.freenode.net and join channel #amsat. If you aren't sure about what IRC is take a look at http://en.wikipedia.org/wiki/IRC. Of course I'll be happy to field any questions here. 73s, Eric W4OTN AMSAT Area Coordinator

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Echo Telemetry website
by Patrick McGrane 31 Jul '07

31 Jul '07

Attention: Mineo Wakita This is patrick N2OEQ, Long island New York Mineo- thank you very much for hosting and posting the website with the Echo telemetry. It was very educational. I dont have 9600 baud capability so I cant recieve the telemetry myself. Please post again from time to time. 73, pat

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Re: [eu-amsat] AO-7 report.
by John Hackett 31 Jul '07

31 Jul '07

Drew, It is my understanding from recent correspondance with W3GEY/VK3GEY Jan King ... (Jan 'built' AO-7) ... and earlier correspondence with N1JEZ Mike Seguin (AO-7 control operator) when I first posted the mail re: the timer last year .... that the timer is completely random when the satellite comes out of eclipse and since there are no imminent occurances of eclipse as far as I can see, I assume the mode will not change unless anything 'ontoward' occurs to upset the electronics. High power *can* affect how the control systems behave ... (obviously, I'm not going to mention the command parameters or the power required). If my assumption is wrong, I stand corrected. In either case, listening to the regular operators will confirm the mode. The mode changes can be viewed at ... <http://www.planetemily.com/ao7/stats2.php> The predected eclipse chart at ... <http://www.planetemily.com/ao7/Eclipse.php> Perhaps other operators will obtain different conclusions from the above predictions. Opinions are are invited. That is, after all, precisely why we started the EU-Amsat reflector. I CC'd this mail to the amsat-bb since the number of Stateside users has increased in the last 2 months and this information may be of interest to them too. 73 John. <la2qaa(a)amsat.org> ........................................................................................................................................... >From: Andrew Glasbrenner <glasbrenner(a)mindspring.com> >Reply-To: eu-amsat(a)yahoogroups.com >To: eu-amsat(a)yahoogroups.com >CC: amsat-bb(a)amsat.org >Subject: Re: [eu-amsat] AO-7 report. >Date: Tue, 31 Jul 2007 11:18:04 -0400 (GMT-04:00) >Every time this has happened in the past, several times over the past few >years, the 24hr timer has >activated, switching between A and B. There is >no reason to expect it won't again. > >73, Drew KO4MA ........................................................................................................................................... >From LA2QAA. >A study of the AO-7 eclipse charts for the last 3 years shows a progression >toward non-elipse orbits in late 2007 - 2008. > >In effect, this means that AO-7 in all probability will not change mode >unless anything untoward happens. > >It also means that we appear to have a permanent mode-B LEO linear >transponder for the forseeable future ... providing operators follow the >recommended operating proceedure. > >Please *do* decrease your power as the satellite approaches TCA to avaoid >FM'ing. > >This not only helps the satellite, it helps the other operators in the >passband. > >Don't be fooled by propagation anomolies. The mode-B transponder is working >well and will continue to do so providing the alligators go and play >somewhere else. Under normal circumstances you do NOT !! need a lot of >power. Please use only the necessary to maintain adequate communications. >If >you can't copy people adequately, you should improve your receiving >capabilities rather than increasing your uplink power ... remember, >aluminium is cheap and it's a lot more user friendly to everyone concerned >.... with perhaps the exception of your neighbours. > >For all intents and purposes, AO-7 is a QRP satellite. Please treat it as >such. > >73 John. <la2qaa(a)amsat.org>

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NLASO website
by Bruce Robertson 31 Jul '07

31 Jul '07

Fred: Let me join the chorus of well-wishers for your group's project. In my opinion, it is an excellent one to undertake: the triple-cubesat design seems just about right in terms of volume; and by documenting and open-sourcing your work, you will provide an fine basis for others who might want follow in your footsteps. I think especially of future collaborations between amateurs and university programs, where the amateurs provide the comms expertise, and the university funds a research project, at whose end the comms. are used for amateurs, much like Delfi C3. I note also the Sat on a PCB concept at http://wiki.amsat.dk/index.php I hope in contrast that your project will seriously consider a linear transponder. I think that the clever social engineering of the VO-52 folks has proven that a linear transponder can successfully be shared around the globe by FM users where necessary and SSB/CW users in places where this is a more sensible use of the device. 73, Bruce VE9QRP

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