July 2011 - AMSAT-BB - mailman.amsat.org

Re: ISS Message Board
by John Becker 26 Jul '11

26 Jul '11

At 12:21 PM 7/26/2011, you wrote: >>>...he is just using the available resources. >I too thought the amateur digital radio equipment on ISS are resources we all can use. I'm sure all of us would not knowingly hog it up for our own benifit... Me too but I'm a bit confused for what. Some seem to use it to post that APRS location Others (who seem to be limited to VHF & UHF) are trying way way to hard to work DX. I may be wrong but they are the reason I have given up completely on it. John, W0JAB John, W0JAB

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Liberty Bell 7
by B J 26 Jul '11

26 Jul '11

With the attention on the end of the final space shuttle mission, the 50th anniversary of the flight of MR-4/Liberty Bell 7 was overlooked. It was the second mission of the Mercury program with Gus Grissom as pilot. http://www-pao.ksc.nasa.gov/history/mercury/mr-4/mr-4.htm 73s Bernhard VA6BMJ @ DO33FL

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LA4FPA JP22
by John Papay 26 Jul '11

26 Jul '11

Erling, LA4FPA, will likely be on the AO-7 pass today around 1952utc. You can track him on aprs.fi using LA4FPA-9. He has been operating from JP32 but is planning for JP22 today. Good luck. 73, John K8YSE

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Doppler Correction?
by John Papay 26 Jul '11

26 Jul '11

The purpose of full doppler correction is to keep your signal in the exact same spot on the receiver in the satellite. It has a finite passband and if you don't correct your uplink, you move within that finite passband. Theoretically a single linear transponder can support many conversations but it will not support the maximum unless everyone stays put at the satellite receiver. Those who don't doppler correct slide within the passband and run into those who are staying put. Of course if you adjust your uplink so you stay put at the satellite, you have to adjust your receiver to hear yourself because of the doppler shift in the other direction. Both uplink and downlink require doppler correction in this case. If you don't have a rig that can be computer controlled or if you are operating portable and can't readily incorporate a laptop into your setup for whatever reason, then by all means manually adjust the highest frequency since that is the one that changes three times faster than the lower frequency in a v/u satellite. You simply do the best you can. However, if you have a home rig that can be computer controlled, then by all means use a computer to adjust your doppler. Stay in one spot in the satellite's passband. You can make faster contacts since you only have to pick up the mic to talk or use the key to send cw. If you are working dx and the window is short, being on frequency and staying put will help put that distant grid in the log. The program does all the work but you must be sure that your keps are current AND your computer clock is accurate to the second. On a high pass when the satellite is overhead, the doppler changes very fast and even a few seconds of clock inaccuracy will have you not hearing yourself in a normal voice. At lower elevations the doppler is not as severe so a few seconds won't make much difference. Use the HO-68 beacon to test your doppler correction. Set your radio for CW with a 500 Hz or better bandwidth. Pick a high pass where the bird will get up over 45 degrees. Tune the beacon in at your AOS and then don't touch the dial. If the CW note stays constant over the entire pass, your system is operating perfectly. Make sure your program settings are such that there are frequent frequency updates. I have mine set at 1 second no matter what. Some older radios will not accept frequency changes while you are transmitting. In that case, make sure you only key down for short periods of time so the radio frequency can be updated. Of course you must adjust your uplink calibration on SatPC32 so that you hear yourself on the downlink. Hearing yourself in a normal voice will be an indication that you have your calibration set properly. Most of the birds stay on frequency, but I've noticed that AO-7 Mode B will be off by 1700Hz when it changes from Mode A to Mode B. Normally we would not observe this phenomenon but since lately we have had this mode change while over North America we are able to experience it. Within a few minutes, the satellite is down to a 1200 Hz offset. I'm not sure what happens on the next pass because it is out of my footprint. The next morning, however, the bird is back to my normal setting. This means the frequency drifts about 1700 Hz back down to it's steady state value. The other birds may have some slight drifting, probably due to spacecraft temperature but it is minimal, less than a few hundred Hz. So when you are trying to make a contact on the first AO-7 pass in Mode B, be prepared to readjust your uplink calibration so you can hear yourself. It may be as much as 1700Hz at the start. In my opinion, everyone that can control their radio for doppler should do so. Doppler correction gives us the maximum usage out of our linear transponders. Why go through the agony of fiddling with your radio when your computer can make your life so much easier. You will never have to apologize for not being on frequency. If I wasn't able to have doppler control on my radio, I wouldn't spend much time on the linear birds, unless of course there was a rare grid to be worked. <grin> 73, John K8YSE

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Trip Report - CN90 Portable Northern California
by David Palmer KB5WIA 26 Jul '11

26 Jul '11

Hi Everyone, This weekend I was able to sneak in some satellite operating during a camping trip with my XYL. We went up to Eagle Lake in Lassen National Forest, which is in Northern California and grid CN90. I had no idea if satellite operation would even be possible from that location (time-wise or terrain-wise) but it turned out it was pretty good! The lake had low mountains around it, not more than a few degrees above the horizon in all directions. I was able to work quite a few satellite passes there, and it was a lot of fun talking to friends in the sat community from that somewhat remote location! The equipment worked well, and I learned the importance of verifying the computer has updated keps before leaving home! My netbook computer had keps that were several months old, which made computer-aided tuning of the linear birds almost impossible! Ugh, lesson learned, and another opportunity to practice manual tuning. Patrick's suggestion of headset and voice recorder really worked well though! I've put some pictures on the website at: http://kb5wia.blogspot.com/2011/07/camping-and-satellites-grid-cn90.html Anyone who worked me and wants a QSL card, just send me an email. 73 de Dave KB5WIA

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ND9M/P: DM35 / DM36
by claryco＠aol.com 26 Jul '11

26 Jul '11

Cori and I will be on from DM36 (possibly the grid line with DM35) on AO27 tomorrow (Monday) at 25/2043Z (approx turn on at 2047Z). Later on, we'll head south a bit and be on from DM34 and then green stamper DM33 after that. I don't know what pass(es) that will be however, but I know that Patrick, WD9EWK, has got those two pretty well covered anyway. We're still running all Arizona counties on HF CW and SSB, which really puts a dent in efficient grid ops, but we'll be turning toward the northeast in a couple days. Then we'll head for the much-in-demand DM66 grid in NM shortly after that. Also, now that we're back in AZ, tracking via APRS (ND9M-7) is more reliable again. 73, Jim, ND9M / VQ9JC Flagstaff, AZ / DM66

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ARISSat-1 Battery
by Clint Bradford 25 Jul '11

25 Jul '11

OK - Charging of the ARISSat-1's battery is scheduled for July 27. And a test this weekend. Will the battery be charged a second time - before EVA-29 on August 3? What is the expected/anticipated battery "charge state" to be after the July 30 test? Good enough for deployment without another charge? Clint Bradford, K6LCS

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ISS Views STS-135 Re-entry
by Clint Bradford 25 Jul '11

25 Jul '11

NASA PHOTO - http://www.nasa.gov/images/content/573236main_iss028e018218_full.jpg Station Crew Views Shuttle Landing This unprecedented view of the space shuttle Atlantis, appearing like a bean sprout against clouds and city lights, on its way home, was photographed by the Expedition 28 crew of the International Space Station. Airglow over Earth can be seen in the background. Image Credit: NASA I have run out of monitors for all these incredible "screensaver/wallpaper" NASA photos ... Clint Bradford, K6LCS

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Steve Bible blogs about ARISSat-1 on EE Times web site.
by Joe Fitzgerald 25 Jul '11

25 Jul '11

Our friends at Microchip are stirring up some interest in our project outside the ham radio world. http://www.eetimes.com/electronics-blogs/chips-in-space/4218140/The-Buildin… -Joe KM1P

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Guildford Talk - The Interplanetary Internet by Lloyd Wood
by Trevor . 25 Jul '11

25 Jul '11

The Amateur Radio satellite OSCAR-36 (UoSAT-12) and the UK-DMC satellite were used for the first tests in space of the "Interplanetary Internet" Lloyd Wood PhD, MSc, MEng, CEng MIET of the University of Surrey Centre for Communication Systems Research (CCSR) will be giving a talk to the AMSAT-UK International Space Colloquium about this exciting pioneering work in bringing the Interplanetary Internet and terrestrial Internet together. His talk will describe how pioneering tests of computer networking on Surrey Satellite Technology's satellites (UoSAT-12 and UK-DMC) were able to integrate the satellites with the terrestrial Internet, and then conduct the first tests in space of the "Interplanetary Internet" that is designed for NASA's deep space missions. The talk takes palce 16:10 - 16:50 BST on Satuday, July 30, there will be a live webstream at http://www.batc.tv/ch_live.php?ch=3 IPv6 in space http://info.ee.surrey.ac.uk/Personal/L.Wood/dtn/interplanetary-internet Delay-Tolerant Networking work: http://personal.ee.surrey.ac.uk/Personal/L.Wood/dtn/ John Lloyd http://www.ee.surrey.ac.uk/CCSR/profiles?s_id=5839& The AMSAT-UK International Space Colloquium to be held July 30-31 at the Holiday Inn, Guildford, GU2 7XZ, England. The event is open to all. Either day passes or full packages comprising overnight accommodation and meals are available. For futher information see http://www.uk.amsat.org/colloquium-2011/ The Colloquium schedule, times in BST (GMT+1), is at http://tinyurl.com/2011ColloquiumSchedule The Spring issue of the AMSAT-UK newsletter OSCAR News can be downloaded free at http://www.uk.amsat.org/on_193_final.pdf Join AMSAT-UK at http://tinyurl.com/JoinAMSAT-UK/ ----

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