Newbie question about AO-07
For some reason, I cannot seem to find info which indicates the mode for the pass...mode A or B. I usually figure it out after listening on 145 downlink and not hearing anything then going to the 29 MHz downlink. Once, I even heard my downlink on 29.45 MHz at the start of the pass only to hear it stop. Was not sure what happened until I started tuning around and discovered the bird had SWITCHED from mode A to mode B in the middle of the pass! So my question is...other than trial and error or listening for the beacons (which won't help if the bird switches during the pass), is there any pattern or location of information for the prediction of the mode? Thanks, as I am thrilled each time I can get through this oldie-but-goodie with 5 watts on CW. What a blast!
An additional question since the batteries have long ceased to function on AO-7, it only works during sunlight passes. Somebody mentioned that this will happen less and less as we get close to winter solstice. Is this because AO7 is in a northerly LEO orbit? If it passes in the southern hemisphere, would it not have MORE available online time? I see http://planetemily.com/ao7/Eclipse.php but it's not a predictor for November 2008 (and I am not sure I understand it anyway). Should I just set Orbitron/HRD for AO7 "in sunlight/illumination" only option?
Mark Lunday WD4ELG wd4elg@arrl.net http://wd4elg.net
AO-7 happens to be in "permenantly sun-lit" conditions. I believe this current period to last fairly long, but I forget now just how much longer, but I think it's on the order of months. AO-7 has a time counter that controls the mode A/B toggle therfore, it will change modes every 24 hours starting at whatever moment the last sun-rise for the spacecraft was(sometime in early August), and always starting in mode-B.
You can look at the logs on http://www.planetemily.com/ao7/main.php , to figure out what mode the satellite was most recently used. I just read the log, and found that the A/B changeover time, these days, is approximately 20:55 UTC. It's likely that the last sunrise AO-7 experienced must have been about 20:55 on Aug 5.
When not in continuous sunlight, it mostly stays in mode-B, never making it the full 24 hours to switch, since the eclipse happens every orbit, or about 1 hour 55 min, for some portion of those orbits.
I'm always impressed when I think about the like-a-rock reliability this old craft has shown! I look forward to perhaps a future craft being launched that is built using the old-style analog hardware prevalent in this old bird.. Something retro, maybe with the old hand-laid harnesses, a clever battery-failsafe scheme, and a dose of enhanced-performance components, it might just last forever!
73's Auke
----- Original Message ----- From: "Mark Lunday, WD4ELG" mlunday@nc.rr.com To: amsat-bb@amsat.org Sent: Friday, October 31, 2008 7:04 PM Subject: [amsat-bb] Newbie question about AO-07
For some reason, I cannot seem to find info which indicates the mode for the pass...mode A or B. I usually figure it out after listening on 145 downlink and not hearing anything then going to the 29 MHz downlink. Once, I even heard my downlink on 29.45 MHz at the start of the pass only to hear it stop. Was not sure what happened until I started tuning around and discovered the bird had SWITCHED from mode A to mode B in the middle of the pass! So my question is...other than trial and error or listening for the beacons (which won't help if the bird switches during the pass), is there any pattern or location of information for the prediction of the mode? Thanks, as I am thrilled each time I can get through this oldie-but-goodie with 5 watts on CW. What a blast!
An additional question since the batteries have long ceased to function on AO-7, it only works during sunlight passes. Somebody mentioned that this will happen less and less as we get close to winter solstice. Is this because AO7 is in a northerly LEO orbit? If it passes in the southern hemisphere, would it not have MORE available online time? I see http://planetemily.com/ao7/Eclipse.php but it's not a predictor for November 2008 (and I am not sure I understand it anyway). Should I just set Orbitron/HRD for AO7 "in sunlight/illumination" only option?
Mark Lunday WD4ELG wd4elg@arrl.net http://wd4elg.net
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I'm always impressed when I think about the like-a-rock reliability this old craft has shown! I look forward to perhaps a future craft being launched that is built using the old-style analog hardware prevalent in this old bird.. Something retro, maybe with the old hand-laid harnesses, a clever battery-failsafe scheme, and a dose of enhanced-performance components, it might just last forever!
Auke, you've hit it on the nose!! The recent generation of "amsat generals" were obsessed or promoted by some ulterior motive other than promoting "amateur satellite communications" under the guise of education..and I suspect some ones finances were involved....I've been in licensed for over 50 years, and we've kept it alive by demos, discussions and education, not by some "go to the store and buy a push button radio" to make it easy!! AO51 FM voice!! Waste of money...
We still see some justifying it under the guise of "education"... hog rot!!
When one promotes something similar to a cell phone operation, I cannot imagine much intrigue??
The last convention sort of proves my point...One report I saw said 80 attendants. Perhpaps some one has an accurate accounting??
We used to have several hundred....
And we never had to promote NASA!! Seems like that should be the other way around...Old ESA is the one to be thanked!!
I think the new board will change some things....
73, Dave, WB6LLO dguimon1@san.rr.com
Disagree: I learn....
Pulling for P3E...
Dave Guimont wrote:
discussions and education, not by some "go to the store and buy a push button radio" to make it easy!! AO51 FM voice!! Waste of money...
What a good job we don't all have the same opinions! The world would be such a dull place...
I think the AO-51 QRP FM modes are great. As a relative newcomer to the hobby (I've been working with commercial radio equipment and electronics for years, and my Dad was an amateur, so I'm more than familiar with the concepts - it's just I've only had my licence a few months) I'm currently restricted by my licence to commercially-produced radios. So, for a lot of people "go to the store and buy a push button radio" is the only way in.
With the QRP FM modes on AO-51 I can work contacts all over Europe and (at least in theory) Africa, Iceland and the Nordic countries. All I need to do this is a little dual-band HT and a homebrew crossed yagi. The aerial and diplexer cost about £5 and took an hour to make, and has rewarded me with about a dozen contacts on AO-51, SO-50 and even one on AO-27 which normally seems to be switched off when it passes over here. So there I have a setup that I can bungee to the back of my bike, or throw on the back seat of the car, or even just carry about with me if there aren't too many people about to get poked by the elements.
Unfortunately the "non-QRP" modes seem to be dominated by the 1kW-into-four-stacked-18-element brigade, who just drown everyone else out. I don't see the point in that, where's the fun in spending all that money putting up a tower and buying a rotator and a set of huge antennas, just to make it easy?
Gordonjcp MM3YEQ
Hello Gordon,
Sorry to hear that you're having a tough time on the non-QRP "pair" on AO-51. Admittedly, it can be frustrating - but don't give up on it. It can be done! I earned Satellite VUCC all handheld with a Yaesu HT and an Arrow antenna, and earned the AMSAT achievement award for 20 states and Canada using only contacts I made running 50 mW (.05-watt) rf out on the same set of 2 AA Duracell batteries. I ended up making a total of 51 contacts at .05-watt and another three at .3-watt (300 mW) rf out before those batteries gave up the ghost. I mention that because only 11 of those 54 total contacts were made on the "QRP pair" on AO-51. I was in the middle of the unorganized mayhem with everyone else for the other 43, on AO-51 and also on AO-27 and SO-50; so, as I said, don't give up. It can be done!
I've said it here before and I'll say it again - I am having more fun on the satellites than I've ever had in amateur radio. And if I hadn't had the ability to start out with a handheld station, I would not have made the necessary investments for all-mode radios, antennas, az/el rotators, etc. I'll never understand how anyone can characterize as a waste of money an activity that inarguably helps operators refine the skills they would most need in a true emergency-communcations situation -- that is, the ability to transmit and receive pertinent information quickly and accurately with minimal repetition. It also seems to me that those of us who regularly use handheld satellite stations are refining those skills on the kind of gear that is among the most necessary and utilized in emergencies.
73 to all,
Tim - N3TL AMSAT Member No. 36820 Athens, Ga. - EM84ha -------------- Original message from Gordon JC Pearce MM3YEQ gordonjcp@gjcp.net: --------------
Dave Guimont wrote:
discussions and education, not by some "go to the store and buy a push button radio" to make it easy!! AO51 FM voice!! Waste of money...
What a good job we don't all have the same opinions! The world would be such a dull place...
I think the AO-51 QRP FM modes are great. As a relative newcomer to the hobby (I've been working with commercial radio equipment and electronics for years, and my Dad was an amateur, so I'm more than familiar with the concepts - it's just I've only had my licence a few months) I'm currently restricted by my licence to commercially-produced radios. So, for a lot of people "go to the store and buy a push button radio" is the only way in.
With the QRP FM modes on AO-51 I can work contacts all over Europe and (at least in theory) Africa, Iceland and the Nordic countries. All I need to do this is a little dual-band HT and a homebrew crossed yagi. The aerial and diplexer cost about £5 and took an hour to make, and has rewarded me with about a dozen contacts on AO-51, SO-50 and even one on AO-27 which normally seems to be switched off when it passes over here. So there I have a setup that I can bungee to the back of my bike, or throw on the back seat of the car, or even just carry about with me if there aren't too many people about to get poked by the elements.
Unfortunately the "non-QRP" modes seem to be dominated by the 1kW-into-four-stacked-18-element brigade, who just drown everyone else out. I don't see the point in that, where's the fun in spending all that money putting up a tower and buying a rotator and a set of huge antennas, just to make it easy?
Gordonjcp MM3YEQ
Sent via AMSAT-BB@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
n3tl@bellsouth.net wrote:
Hello Gordon,
Sorry to hear that you're having a tough time on the non-QRP "pair" on AO-51. Admittedly, it can be frustrating - but don't give up on it. It can be done! I earned Satellite VUCC all handheld with a Yaesu HT and an Arrow antenna, and earned the AMSAT achievement award for 20 states and Canada using only contacts I made running 50 mW (.05-watt) rf out on the same set of 2 AA Duracell batteries. I ended up making a total of 51 contacts at .05-watt and another three at .3-watt (300 mW) rf out before those batteries gave up the ghost. I mention that because only 11 of those 54 total contacts were made on the "QRP pair" on AO-51. I was in the middle of the unorganized mayhem with everyone else for the other 43, on AO-51 and also on AO-27 and SO-50; so, as I said, don't give up. It can be done!
See, that's the thing - I *have*, on quiet passes, got into the non-QRP transponder on AO-51, usually before the rest of Europe is awake ;-) When QRP mode is in use people do seem to spend a bit more time listening. The whole "feel" of the QSO is different, somehow - people seem to be taking more care over it.
In the QRP modes, I can't quite get it with 50mW but the 500mW mode on my HT is plenty - enough to get in. With 5W into the aerial I get pretty much full quieting once the satellite is well up. I know the aerial must be pretty effective, because I can lift one of the more distant repeaters with full quieting on 500mW, that I can barely even hear with the rubber duck!
Not bad, I thought, for something built (as I've probably said before) out of a scrap length of wood, some ally tubing, some hydraulic pipe for the driven element (kunifer - bit too floppy really, but it's what was lying about) and some brazing rods for the 70cm part.
I've said it here before and I'll say it again - I am having more fun on the satellites than I've ever had in amateur radio. And if I hadn't had the ability to start out with a handheld station, I would not have made the necessary investments for all-mode radios, antennas, az/el rotators, etc. I'll never understand how anyone can characterize as a waste of money an activity that inarguably helps operators refine the skills they would most need in a true emergency-communcations situation -- that is, the ability to transmit and receive pertinent information quickly and accurately with minimal repetition. It also seems to me that those of us who regularly use handheld satellite stations are refining those skills on the kind of gear that is among the most necessary and utilized in emergencies.
Exactly. If you really are in an emergency, you're not going to be able to pop online and order a nice new antenna from Waters and Stanton, now are you?
Gordon
participants (5)
-
Auke de Jong -
Dave Guimont -
Gordon JC Pearce MM3YEQ -
Mark Lunday, WD4ELG -
n3tl＠bellsouth.net