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

Skeds on AO-07 mode B in CW.
by LU2DPW Juan Cralos 25 Nov '08

25 Nov '08

Hi Sat Fans!! I'm very interesting sked with Central America, Caribean and South Florida stations for possible DX contact on AO-07 Mode B on CW at night passes. I'm worked stations WP4CNU form Puerto Rico and AA4FL & W4DFU from FL,USA in good conditions. I work with minimal elements: FT-726R with 10 W input and my antennas are: a Quad Swiss for VHF and Vertical Diamond X-200 for UHF. Please contact with my e-mail address: lu2dpw(a)yahoo.com.ar Many thanks and see you on CW in this beatifull bird!! 73 all Juan LU2DPW GF05gi Yahoo! Cocina Recetas prácticas y comida saludable http://ar.mujer.yahoo.com/cocina/

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ICOM -820 repair :-(
by Alvaro de Leon Romo 25 Nov '08

25 Nov '08

Hi , after several years my IC820 have some problem , the radio not respond to instructions about to input the high and low power level and now not transmit :-( Some one here know what is the better way to fix this radio ? ICOM AMERICA is the best choice ?? I will fly to Tx so I need the info where to send the radio to reapair ... Is the cost too high ? Many thanks for your valious time Sincerely Al XE2AT _________________________________________________________________ Realiza búsquedas en Internet y llévate hasta ¡Un Auto! http://www.ganabuscando.com/Default.aspx

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another idea for a sat
by Eric Fort 25 Nov '08

25 Nov '08

What would you think of a sat that required no user frequency control for uplink or downlink and carried somewhere between 10 and 30 simultanious conversations? Here's how it can be done and it's a mode that I think deserves more investigation - ACSB, possibly with a twist. for those not familiar with ACSB, it's essentially SSB with a subaudable tone inserted. on recieve that subaudable tone of known frequency can be used for tuning and doppler adjustment. Taken a step further one could use the on sat beacon as the reference "tone" and simply maintain a frequency exactly a certain distance from that. come to think of it we could experiment with this now on the ssb birds we have now. anyone interested in trying this? has it been tried? what do you think? Eric AF6EP

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Re: bbsat ideas...
by k9jkm＠comcast.net 25 Nov '08

25 Nov '08

> Maybe we can fill unused slots with telemetry? Or how about designing a digital channel that features 16 or 32 "slots" accessible to both amateur radio communication and telemetry/control for the cubesat team? Our design could include something like a 50/50 split in bandwidth between amateur radio and the cubesat telemetry. A well-defined user interface document would give the cubesat team access to their bandwidth. By solving the radio problem for the cubesat team we become a part of the mission and we would have a reason for being aboard just about every cubesat in the future. -- 73 de JoAnne K9JKM k9jkm(a)amsat.org

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SO-50 pass at 0728Z tonight
by Bryan Green 25 Nov '08

25 Nov '08

OK, you crazy satellite operators -- it's your newbie here. I shall be active on the 0728Z SO-50 pass tonight. I want to see how far East I can make it. Insomniac operators, have a listen for me, if you would please, and thanks in advance! -- bag KL7CN/W6 CM98fn

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Re: ICOM -820 repair
by Clint Bradford 24 Nov '08

24 Nov '08

> IC-820 repair... Icom hasn't had parts for this rig for over a decade. You are going to have to search the Web for repair people, and ask them how familiar they are with your radio. Clint Bradford, K6LCS / KAF3359 909-241-7666

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viewing iss
by Eric Fort 24 Nov '08

24 Nov '08

on what passes should I be able to see ISS? does it need to be illluminated to see or can it still be seen in eclipse? what magnitude is needed to see it with bare eyes? Eric AF6EP

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AO7 MODE A ORBIT 55724 - Lots of activity!
by Mark Lunday, WD4ELG 24 Nov '08

24 Nov '08

Worked Ed, W0ODD, in Kansas on CW. Heard a bunch of SSB stations. Great signals on mode A. Nice to hear activity! Exciting!! Mark Lunday WD4ELG wd4elg(a)arrl.net http://wd4elg.net

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Re: thought for a neat product, anyone seen one?
by Mark Vandewettering 24 Nov '08

24 Nov '08

I have the same rig, and much the same idea. I haven't gotten very far along with this idea, but here's where my thinking takes me. I've implemented Miller's "Plan 13" algorithm in Python, and currently use it to plan all my satellite operations. On any reasonable laptop, it runs many times faster than real time, even while running in Python, so it seems like overkill to carry a laptop with you to do satellite operations. The laptop is expensive, bulky, and hard to use in the field while aiming an antenna by hand, has limited battery life, etc. Clearly, a more limited computer can do all that we really need. If you look at G6LVB's latest/ greatest antenna tracker: http://www.g6lvb.com/Articles/LVBTracker2/index.htm you can see that he does all that you want using just a PIC microcontroller. My own personal bias is against the PIC though: I prefer the Atmel AVR chips, and in particular have been having a great deal of fun with the Arduino microcontroller board. I suspect that if I back ported my Python code into C and put it on the Arduino, I could still get an update rate approaching 1Hz, which should be good enough for the purposes we desire. The Arduino also has a nice little piggyback ethernet board. Here's what I imagine the usage is. While at home, you plug this thing into your home network. It then contacts celestrak or whatever, and automatically downloads the TLE for current amateur satellites. You can then disconnect the rig from your home network, and it's ready to carry into the field. A couple of buttons on the box allow you to cycle through satellites, giving the elevation and azimuth of the satellite. The Arduino also has a serial port which we can hook to the FT-817, and use it to control the 817 with doppler. It would be a pretty simple project, requiring three modules (arduino, ethernet shield and display) and a few extra buttons etc... Total cost probably around $100 or so. Could probably run off batteries for days. I probably won't get back to working on this until after the first of the year, but if anyone is interested, some enthusiasm might further motivate me to get the software working. Mark

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thought for a neat product, anyone seen one?
by Eric Fort 24 Nov '08

24 Nov '08

Interesting you mention gumstix, it was one of my first ideas for hardware to base something like this on. the nice thing about basing something like a tracker on gumstix is all the software is already written. It should run predict directly or most any other curses based linux app, or for that matter your favorite script interpreter, etc. I also found the lvb tracker 2 shortly after I asked but that seems not to have gone anywhere. It's probably the closest thing to what I'd be looking for but it seems a bit large to lug around as would be a laptop. mostly what I would be looking for is a small unit that I could directly use for frequency control but I'm realizing now that once there you've built that you are only a few transistors away from a full tracker. maybe amsat (or tapr) could do a gumstix refrence platform. Eric AF6EP On Mon, Nov 24, 2008 at 5:06 AM, Ben Jackson <bbj(a)innismir.net> wrote: > Eric Fort wrote: > > I just thought of kind of a neat product for those of us that work sats. > > Has anyone seen anything similar? I have an ft-817 which has a cat > > interface and will operate both ssb and fm. Has anyone seen a little box > > that would adjust the radio frequency for both uplink and downlink while > > displaying azmuth and elevation data? It seems that it would be handy to > > have the frequency control take care of itself while providing data as to > > where I should point the arrow. What do those reading this idea think of > > it? It would seem to me to be quite useful especially for ssb. > > I think it was Mark VandeWettering, KF6KYI, who had a similar idea a few > months ago. Last I heard I think he was toying around with the idea of > using a Gumstix (http://www.gumstix.com/)device<http://www.gumstix.com/%29device>to be the "black box." - > There was a reason he didn't pursue it, but I forget why. > > This is a easily extensible system that can be hacked up to control > doppler and handle basic radio functions. One could probably have a > simple system banged out in an afternoon. As it gets more complicated > (external display to control satellite selection, etc) it gets a touch > harder to make, but still within the realm of possibility. The good part > about Gumstix is that you don't need to get the hardware first to start > working on the software, as it's all based on Linux. > > I think this idea has a lot of promise, and if I had a transceiver that > could computer control, I'd probably start designing it. :) > > -- > Ben Jackson - N1WBV - New Bedford, MA > bbj <at> innismir.net - http://www.innismir.net/ >

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