September 2006 - AMSAT-BB - mailman.amsat.org

San Diego Meeting report
by Jim Sanford 14 Sep '06

14 Sep '06

All: It has come to my attention that the San Diego meeting report has format problems. I've ZERO idea how the format got gooned. I have taken it offline for correction. I will advise, tomorrow or Saturday, when I've fixed the format and reloaded. Thanks & 73, Jim wb4gcs(a)asmat.org James A. Sanford, PE Amsat Eagle Project Manager

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The Eagle has died, my original point.
by Keith Bainbridge 14 Sep '06

14 Sep '06

As I started this thread perhaps I should finish it. My original point was the ratio of Satellite operators to experimenters must be about 50:1, so it makes far more sense to put up a bird that people will and more importantly " can " use than continually developing more and more sophisticated modes etc. The biggest thrill I've had in 25 years as a Ham is to work 67 countries and all continents in the 18 months or so that I discovered AO-40. I'd played with AO 7 etc back in 80-81 but this was " FUN " and thats the point I tried to make with my earlier post. I will donate to P3E as it will give me many options to use the gear I already have. There are no other options for me, living in Western Australia, Leo's are a complete waste of time and money, I can talk to myself on every pass on any satellite going over, no one else will be there to reply !! Well maybe the same 2 or 3 people. If Amsat NA must persue the Eagle option then please be prepared to revert back to AO-13 / AO-40 type birds when it fails. Can we finish this hread of mine now please? 73 Keith -- Keith Bainbridge VK6XH & VK6DXR Vice-President Northern Corridor Radio Group ( VK6ANC ) Amsat NA 35338 TenTec Omni VI, FlexRadio SDR 1000 , 5 Band Spiderbeam. Wireless Institute of Australia Previous calls include VK6DXC, VK6BRK,G6HHV, G0HEI & G1GHZ You're just jealous 'cos the voices only speak to me......... http:/www.qrz.com/vk6xh

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Re: The Mode B tradition
by G0MRF＠aol.com 14 Sep '06

14 Sep '06

In a message dated 9/14/2006 10:39:26 PM GMT Standard Time, bill(a)hsmicrowave.com writes: Hi David, Help me out with the 100,000 single point failures. Are you referring to the complexity of digital gates etc., in the DSP. Isn't P3E going with a digital IF or are they using an analog backup or vice versa? That's the SDX thingy isn't it? Regards...Bill - N6GHz Hello Bruce / Dom. I agree, the UV on Eagle will be apparently analog (ue) to the casual user. But be aware Bruce that it's not "primarily" a software driven transponder. It is in fact TOTALLY software driven. There is no linear IF, just DSP in the core. Or from another viewpoint 100,000 single point failures just waiting to happen. 73 David G0MRF Hello Bill. As I understand it, and perhaps I'm being a little over conservative in my concern, The Eagle design has shifted with respect to the caution of engineering that was shown just 14 months ago. My reference to 100,000 single point failures just waiting to happen was aimed at the UV SDX transponders total reliance on some very impressive but completely untried in space digital electronics. From the various messages on the BB in the past 2 weeks I understand that the line up of the transponder is: U band receiver to 10.7MHz - DSP based core processing the signal at baseband - Then an upconversion process that goes to 10.7MHz then 145MHz. This would appear to place the DSP it's software and its control electronics within a critical path which has large potential for a single failure. For example if one of the junctions in the DSP is 'hit', then the transponder stops working. - There is no plan B. OK, Yes it will be radiation tested, but as I pointed out in a previous mail, it will be launched at the peak of the sunspot cycle and orbital manouvers can go wrong leaving the satellite in the wrong part of the Van Allen belts. Let's look at our own history: AO-10 was placed in a high radiation environment and within a short period the IHU died. However, the RF components in the transponder continued to function and the satellite provided a limited service. Why did it continue to function? Well, I can only guess. But how about the possibility that RF devices with large junctions are less vunerable to radiation than sub 1 micron devices in LSI logic. In AO-7, the RF components are still working 20 years on. I have suggested that a simple signal path be designed around the SDX core. Signals appear to exist at 10.7MHz and adding just a few extra components would allow a malfunctioning SDX to be bypassed. What is really curious is that these fears have been voiced before and reassurances were given by Rick W2GPS. However for some reason, what seems to be a prudent, inexpensive and simple option has been dropped in favour of increased trust in radiation testing or by providing an equally vunerable duplicate DSP unit. Please see original question asked by Drew KO4MA with reply from W2GPS dated July 2005. ============================================================== Drew, See the Eagle specification document at _http://www.amsat.org/amsat-new/eagle/Eagle_Fall_2004.php_ (http://www.amsat.org/amsat-new/eagle/Eagle_Fall_2004.php) It says "To provide a safe backup system in case of a failure in the digital implementation of the linear transponders there will be two S-Band transmitters and either of them will be capable of being driven by the SDR driver or by a traditional analog linear driver. One or more of the receivers will also be capable of analog operation." Rick W2GPS AMSAT LM 2232 -----Original Message----- From: owner-Eagle(a)AMSAT.Org [_mailto:owner-Eagle@AMSAT.Org_ (mailto:owner-Eagle@AMSAT.Org) ] On Behalf Of Andrew Glasbrenner Sent: Sunday, July 24, 2005 7:45 PM To: Robert McGwier; Amsat-Bb Cc: Jim Sanford Subject: [eagle] Re: [amsat-bb] LONG and long overdue report Hi Bob, Thank you very much for the update on the Eagle transponder progress. The SDR based transponders sound very cutting edge and extremely adaptible to AMSAT's needs. I very much look forward to hearing them at the symposium in a few months. I'll have my satellite backpack station that was used for the Dayton demos, and will be glad to offer it up for demonstrating the new transponders. CC Rider is also very exciting and sure to open new realms of small stations and portable operation. As someone primarily looking in from a user/member point of view I would like to offer two comments. First, I'd hate to think we are going to hang our entire mission on just the SDR transponders. Wouldn't it be prudent to include at least a bare bones analog backup transponder? Please tell me this is the plan. Second, I'd like to encourage that software development not lag too far behind the hardware. I'm not a big fan of the idea of writing the code once it's in orbit. One does not have to look too far to find where AMSAT has oversold or overpromised features based on writing the software after launch. Please take these comments in the spirit with which they were offered, with only my desire to see Eagle as succesful as possible. 73 and thanks for your efforts, Drew KO4MA AMSAT #33438

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End of the thread
by Keith Bainbridge 14 Sep '06

14 Sep '06

Frank , I agree, I forgot to mention in my post I was refering to modes U/s and L/S of course. It was great working Brazil with a 1 degree inclination and a 4 minute window to give me WAC on Ao-40, incl antarctica. I cant even work South America on HF from Western Australia, well its damned difficult ! Hopefully we can repeat the fun on P3E, it's contacts in the log that count not which exotic mode was used as far as I'm concerned. See you on P3E one of these days 73 Keith -- Keith Bainbridge VK6XH & VK6DXR Vice-President Northern Corridor Radio Group ( VK6ANC ) Amsat NA 35338 TenTec Omni VI, FlexRadio SDR 1000 , 5 Band Spiderbeam. Wireless Institute of Australia Previous calls include VK6DXC, VK6BRK,G6HHV, G0HEI & G1GHZ You're just jealous 'cos the voices only speak to me......... http:/www.qrz.com/vk6xh

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Re: The Eagle has died, my original point.
by Tony Langdon (ATC) 14 Sep '06

14 Sep '06

> already have. There are no other options for me, living in Western > Australia, Leo's are a complete waste of time and money, I > can talk to Hey, it's not much better on the eastern side! I've largely gone quiet on the sats for the time being, but I would like to have a crack at one of the HEO birds when they go up. U/V, I could probably manage now, though I need to sort out the uplink. S band downlink would be possible with a bit of work (been there, covered that issue). Higher bands at this stage are probably prohibitively expensive. Now, I have the luxury of being able to plant a satellite array in the middle of the back yard! :-) Time to use it might be more of a challenge though. ;)

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Not hearing S-band on AO-51
by Michael Tondee 14 Sep '06

14 Sep '06

I've been trying to get a handle on my S-band receiving setup for a couple of months now. It seems when the bird has been in V-S mode that I've had one problem or another that hasn't allowed me to test it. I don't have an L-band antenna up at the moment so I thought I would at least listen to some passes the past couple of evenings to see how my receive would work. I have a AIDC 3731 downconverter and a small BBQ-grill dish on my Az/El rotator system. The IF of the downconverter is at 123 Mhz. I built another converter that was featued in the AMSAT Journal awhile back. The purpose of this converter is to further reduce the 123 Mhz output to 6 meters where I can feed it into my TS-2000X. Unfortunately I haven't heard anything with this setup. I've had some near overhead passes and once my dish gets above about 30 degrees or so it is pointing at clear sky. I thought maybe my homebrew converter was to blame so I dug up an HT that will receive directly on 123 Mhz. Still nothing. I can hear the noise level increase and decrease if I cut power on and off to the downconverter so I assume it's working. Could I be wrong in that assumption? The other thing is that it's been kind of rainy and overcast here the past couple of evenings. Would this affect my reception? I don't know what I should be trying here. It's pretty new to me. I know a BBQ grill dish isn't the best antenna but it seems to me it should work ok considering people hear the bird with this same downconverter and a small corner reflector plus an HT. Any ideas or suggestions out there? TNX and 73, Michael, W4HIJ AMSAT # 36017

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Mode S on AO-40
by Frank A Cahoy 14 Sep '06

14 Sep '06

Sorry Keith, but I must add a bit more gasoline to the fire. Count me absolutely as one of the "operators". My experiences on AO-40 were the most gratifying as a true blue DXer like nothing I've ever encountered on HF. (My alltime HF DXCC total is 364 worked/confirmed.) I worked 93 entities and nearly a 1000 unique callsigns via this bird. My first real time using an HEO. I'd been on AO-10 (Mode B) but it was, toward the end of its life, a hit and miss situation. My favorite DX QSO via AO-40 was with VK9CD. We both had no more than three degrees of elevation and I had to find a "hole" in my neighbor's trees accross the street to do it. The point is I have a QSL card to prove it. I live in a "rural" area, I suppose. Our town is small (1700 pop.) but crap and corruption on the downlink was NEVER a concern for me. Speaking from a purely operators point of view put Mode S back into the game plan. I hope and pray that P3E will soon be up so that this old DXer doesn't go completely stir crazy. 73 to all. Frank, K0BLT

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TAPR DSP56002 EVM FS/Trade
by Mike Lewis 14 Sep '06

14 Sep '06

Hi All: I've got a TAPR DSP56002EVM / Radio Interface that is now excess to my needs. If anyone is interested in a purchase or trade contact me off list. Thanks, Mike K4MPL

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The Eagle has died.
by Keith Bainbridge 14 Sep '06

14 Sep '06

It's a terrible shame that Amsat has choosen not to continue Mode S on Eagle. I for one will no longer send my hard earned cash as a donation to Eagle or Amsat NA,but to Amsat DL as I'm sure many others will do. The expression "Don't bite the hand that feeds you " comes to mind. I have a full Mode L / S setup here sitting waiting unused since the day AO 40 died, what use are LEO's in Western Australia. Sorry Amsat NA but I wont be renewing my membership next time without mode S. 73 Keiith -- Keith Bainbridge VK6XH & VK6DXR Vice-President Northern Corridor Radio Group ( VK6ANC ) Amsat NA 35338 TenTec Omni VI, FlexRadio SDR 1000 , 5 Band Spiderbeam. Wireless Institute of Australia Previous calls include VK6DXC, VK6BRK,G6HHV, G0HEI & G1GHZ You're just jealous 'cos the voices only speak to me......... http:/www.qrz.com/vk6xh

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AO-51 help Bob
by w7lrd＠comcast.net 13 Sep '06

13 Sep '06

Greetings to any and all L'ers. three passes over the US tonight at 0130Z E.Coast, 0300Z Mid West, 0440Z Left coast. Help Bob get some contacts on L/S. I'm still working out the bugs. 73 Bob W7LRD Seattle

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