Re: [amsat-bb] ANS-199 AMSAT News Service Special Bulletin - AMSAT Fox-1C Launch Opportunity Announced
Hi, AMSAT can open a Project at KICKSTARTER in technology tag. https://www.kickstarter.com/discover/categories/technology I saw a lot of project getting 300, 400% more than originally goal. Some of then looks like a stupid idea, but that´s no matter they get the found´s, and what make no sense for me can be a good deal to others :) Already donated via PAYPAL today, but in my opinion would be great if AMSAT-NA use this way also to get founds for the project! Please think about it, I believe that donations don´t need to come only from amateur radio satellite operators, but also from everyone who likes electronics, science and technology. 73 Fabiano Moser CT7ABD PY5RX On Sat, Jul 19, 2014 at 10:50 PM, Phil Karn k...@ka9q.net wrote: On 07/19/2014 02:04 PM, Jerry Buxton wrote: other three would be ready to fly if other opportunities came up. If you're going to spend the time developing them, why not partner for free launches (ELaNa) for more than one? The opportunities for an FM transponder and educational outreach are good. I still have universities looking to partner. Ah, because launches are scarce and expensive, and (re)developing even the same old thing consumes much of AMSAT's limited resources. And they're limited because we have yet to interest more than a tiny niche in what we're doing. It's great to have universities looking to partner, but what do they bring to the table, really? Are we sure they're not just looking for free spectrum? one flying soon, so that we can learn how well they work and apply those lessons to Fox-2 while we're working out the design. We already know how well they'll work because we've done the same thing many times before. I hate to say it, but this is no longer rocket science. The physics is well understood, and those same physics tell us how we could accomplish so much more with our (currently) limited resources. --Phil ___ 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 ___ 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
Re: [amsat-bb] ANS-199 AMSAT News Service Special Bulletin - AMSAT Fox-1C Launch Opportunity Announced
On 07/19/2014 09:23 PM, Robert Bruninga wrote: I cannot believe that. The equilibrium of a nominally black (solar panels on all sides) spacecraft is something like about 0 to 30 C (32F to 90F) a very benign operational range. The only time you DO have thermal issues is when you DO have attitude control and have things that are not equally over time seeing the sun and dark sky. See Dick's paper for the details; I'm just quoting his results. I know the basic physics of heat transfer in space but I would never call myself an expert. He is. But I can do a back-of-the-envelope calculation that tells me he's right. The solar cells they're using have an absorptivity and emissivity that is both 0.98, as I recall, so a cubesat covered with them is essentially a perfect blackbody. A blackbody cube with one face normal to the sun at 1 AU will reach an equilibrium temperature of -21.35 C. The problem is that the ratio of radiating area to absorbing area for a cube is 6:1 (with the sun normal to one surface). A sphere would be warmer because its ratio of radiating to absorbing area is only 4:1. A thin flat plate normal to the sun (like a solar wing) would be even warmer -- 2:1. And that -21.35 C figure is for continuous sunlight. Throw in eclipses and things get much worse. Yes, it would be a little better when the sun shines on a corner rather than normal to a face, and Earth albedo and IR radiation will warm things a little, but not enough to matter. --Phil PS: Temperature of 10 cm blackbody cube at 1 AU: Area facing sun: .01 m^2 Solar constant: 1367.5 W/m^2 Absorbed power = 13.675 W Total radiating area: .06 m^2 Emissivity = 1.0 (perfect blackbody) Stefan-Boltzmann constant = 5.6703e-8 W/(m^2K^4) T = (13.675 W / (5.6703e-8 * 1.0 * .06)) ** (1/4) = 251.8K == -21.35 C ___ 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
Re: [amsat-bb] ANS-199 AMSAT News Service Special Bulletin - AMSAT Fox-1C Launch Opportunity Announced
Hi All, I could start writing all kinds of angry E-mails, but I have always resisted to reply on these kind of threads. I'm glad the AMSAT-BB is not reflecting the great community that is amateur radio and the many exciting things we are doing for our community to keep communications alive. I will go back to work on SDR transponders, D-ATV cubesats, CODEC2 speech downlinks and FUNcube linear transponder improvements, but you guys are not interested I hear, so I will shut up. Wouter PA3WEG On Sun, Jul 20, 2014 at 12:59 PM, Phil Karn k...@ka9q.net wrote: On 07/19/2014 09:23 PM, Robert Bruninga wrote: I cannot believe that. The equilibrium of a nominally black (solar panels on all sides) spacecraft is something like about 0 to 30 C (32F to 90F) a very benign operational range. The only time you DO have thermal issues is when you DO have attitude control and have things that are not equally over time seeing the sun and dark sky. See Dick's paper for the details; I'm just quoting his results. I know the basic physics of heat transfer in space but I would never call myself an expert. He is. But I can do a back-of-the-envelope calculation that tells me he's right. The solar cells they're using have an absorptivity and emissivity that is both 0.98, as I recall, so a cubesat covered with them is essentially a perfect blackbody. A blackbody cube with one face normal to the sun at 1 AU will reach an equilibrium temperature of -21.35 C. The problem is that the ratio of radiating area to absorbing area for a cube is 6:1 (with the sun normal to one surface). A sphere would be warmer because its ratio of radiating to absorbing area is only 4:1. A thin flat plate normal to the sun (like a solar wing) would be even warmer -- 2:1. And that -21.35 C figure is for continuous sunlight. Throw in eclipses and things get much worse. Yes, it would be a little better when the sun shines on a corner rather than normal to a face, and Earth albedo and IR radiation will warm things a little, but not enough to matter. --Phil PS: Temperature of 10 cm blackbody cube at 1 AU: Area facing sun: .01 m^2 Solar constant: 1367.5 W/m^2 Absorbed power = 13.675 W Total radiating area: .06 m^2 Emissivity = 1.0 (perfect blackbody) Stefan-Boltzmann constant = 5.6703e-8 W/(m^2K^4) T = (13.675 W / (5.6703e-8 * 1.0 * .06)) ** (1/4) = 251.8K == -21.35 C ___ 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 ___ 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
Re: [amsat-bb] ANS-199 AMSAT News Service Special Bulletin - AMSAT Fox-1C Launch Opportunity Announced
I was not going to post but since no one else has, I thought there needs to be a correction to a statement made in case some younger people are reading the thread. Phil said: Good analogy, actually. They returned to the moon six times (succeeding on five) because they had excess hardware originally built in the expectation that the first attempts would fail. There were actually seven manned missions to the moon. Six succeeded. Apollo 13 never landed on the moon and returned to earth safely. Apollo 11,12,14,15,16, and 17 landed. 12 American astronauts walked on the moon. Sent from Rick's iPad2 ___ 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
Re: [amsat-bb] ANS-199 AMSAT News Service Special Bulletin - AMSAT Fox-1C Launch Opportunity Announced
I need to receive the foot in mouth award. The key word I read past was They RETURNED to the moon six... I'll just go back to the my radios and hide. Sent from Rick's iPad2 On Jul 20, 2014, at 9:27 AM, Rick Walter wb3...@gmail.com wrote: I was not going to post but since no one else has, I thought there needs to be a correction to a statement made in case some younger people are reading the thread. Phil said: Good analogy, actually. They returned to the moon six times (succeeding on five) because they had excess hardware originally built in the expectation that the first attempts would fail. There were actually seven manned missions to the moon. Six succeeded. Apollo 13 never landed on the moon and returned to earth safely. Apollo 11,12,14,15,16, and 17 landed. 12 American astronauts walked on the moon. Sent from Rick's iPad2 ___ 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
Re: [amsat-bb] ANS-199 AMSAT News Service Special Bulletin - AMSAT Fox-1C Launch Opportunity Announced
I must quickly point out some real data: www.warehouse.funcube.org.uk Which shows an equilibrium of around +20 degrees after 64 minutes of sunlight. Black solar cells on a black surface but some polished Aluminium in the structure. During eclipse, The Earth facing side begins to increase in temperature at around -16 degrees, but then cools down rapidly as the cube rotates. The temperature is still heading down rapidly as it exits eclipse after 34 minutes and at around -24C on the outside surfaces. Thanks David -Original Message- From: Phil Karn k...@ka9q.net To: amsat-bb amsat-bb@amsat.org Sent: Sun, 20 Jul 2014 11:59 Subject: Re: [amsat-bb] ANS-199 AMSAT News Service Special Bulletin - AMSAT Fox-1C Launch Opportunity Announced On 07/19/2014 09:23 PM, Robert Bruninga wrote: I cannot believe that. The equilibrium of a nominally black (solar panels on all sides) spacecraft is something like about 0 to 30 C (32F to 90F) a very benign operational range. The only time you DO have thermal issues is when you DO have attitude control and have things that are not equally over time seeing the sun and dark sky. See Dick's paper for the details; I'm just quoting his results. I know the basic physics of heat transfer in space but I would never call myself an expert. He is. But I can do a back-of-the-envelope calculation that tells me he's right. The solar cells they're using have an absorptivity and emissivity that is both 0.98, as I recall, so a cubesat covered with them is essentially a perfect blackbody. A blackbody cube with one face normal to the sun at 1 AU will reach an equilibrium temperature of -21.35 C. The problem is that the ratio of radiating area to absorbing area for a cube is 6:1 (with the sun normal to one surface). A sphere would be warmer because its ratio of radiating to absorbing area is only 4:1. A thin flat plate normal to the sun (like a solar wing) would be even warmer -- 2:1. And that -21.35 C figure is for continuous sunlight. Throw in eclipses and things get much worse. Yes, it would be a little better when the sun shines on a corner rather than normal to a face, and Earth albedo and IR radiation will warm things a little, but not enough to matter. --Phil PS: Temperature of 10 cm blackbody cube at 1 AU: Area facing sun: .01 m^2 Solar constant: 1367.5 W/m^2 Absorbed power = 13.675 W Total radiating area: .06 m^2 Emissivity = 1.0 (perfect blackbody) Stefan-Boltzmann constant = 5.6703e-8 W/(m^2K^4) T = (13.675 W / (5.6703e-8 * 1.0 * .06)) ** (1/4) = 251.8K == -21.35 C ___ 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 ___ 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
Re: [amsat-bb] ANS-199 AMSAT News Service Special Bulletin - AMSAT Fox-1C Launch Opportunity Announced
Hi Phil, The reality is, even with no battery heater on FUNcube-1 we seem to have an acceptable battery temperature of between 0 and +5C. The temp sensor is, of course, actually external to the battery itself. Our orbit is sun synchronous so we suffer eclipses for approx 33% of the orbit ..but then we are relatively close to the earth! I would also comment that any active attitude control system will consume power...which we don't have much of.. Probably, if you need continuous operation of the radio system, then a 2U with deployable solar panels is the minimum configuration for a CubeSat operating on microwave bands with an active attitude control system. best 73 Graham G3VZV -Original Message- From: g0...@aol.com Sent: Sunday, July 20, 2014 3:41 PM To: k...@ka9q.net ; amsat-bb@amsat.org ; bruni...@usna.edu Subject: Re: [amsat-bb] ANS-199 AMSAT News Service Special Bulletin - AMSAT Fox-1C Launch Opportunity Announced I must quickly point out some real data: www.warehouse.funcube.org.uk Which shows an equilibrium of around +20 degrees after 64 minutes of sunlight. Black solar cells on a black surface but some polished Aluminium in the structure. During eclipse, The Earth facing side begins to increase in temperature at around -16 degrees, but then cools down rapidly as the cube rotates. The temperature is still heading down rapidly as it exits eclipse after 34 minutes and at around -24C on the outside surfaces. Thanks David -Original Message- From: Phil Karn k...@ka9q.net To: amsat-bb amsat-bb@amsat.org Sent: Sun, 20 Jul 2014 11:59 Subject: Re: [amsat-bb] ANS-199 AMSAT News Service Special Bulletin - AMSAT Fox-1C Launch Opportunity Announced On 07/19/2014 09:23 PM, Robert Bruninga wrote: I cannot believe that. The equilibrium of a nominally black (solar panels on all sides) spacecraft is something like about 0 to 30 C (32F to 90F) a very benign operational range. The only time you DO have thermal issues is when you DO have attitude control and have things that are not equally over time seeing the sun and dark sky. See Dick's paper for the details; I'm just quoting his results. I know the basic physics of heat transfer in space but I would never call myself an expert. He is. But I can do a back-of-the-envelope calculation that tells me he's right. The solar cells they're using have an absorptivity and emissivity that is both 0.98, as I recall, so a cubesat covered with them is essentially a perfect blackbody. A blackbody cube with one face normal to the sun at 1 AU will reach an equilibrium temperature of -21.35 C. The problem is that the ratio of radiating area to absorbing area for a cube is 6:1 (with the sun normal to one surface). A sphere would be warmer because its ratio of radiating to absorbing area is only 4:1. A thin flat plate normal to the sun (like a solar wing) would be even warmer -- 2:1. And that -21.35 C figure is for continuous sunlight. Throw in eclipses and things get much worse. Yes, it would be a little better when the sun shines on a corner rather than normal to a face, and Earth albedo and IR radiation will warm things a little, but not enough to matter. --Phil PS: Temperature of 10 cm blackbody cube at 1 AU: Area facing sun: .01 m^2 Solar constant: 1367.5 W/m^2 Absorbed power = 13.675 W Total radiating area: .06 m^2 Emissivity = 1.0 (perfect blackbody) Stefan-Boltzmann constant = 5.6703e-8 W/(m^2K^4) T = (13.675 W / (5.6703e-8 * 1.0 * .06)) ** (1/4) = 251.8K == -21.35 C ___ 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 ___ 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 ___ 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
Re: [amsat-bb] ANS-199 AMSAT News Service Special Bulletin - AMSAT Fox-1C Launch Opportunity Announced
a different slant-not wanting to enter the fm vs linear ongoing debate or the easy sat concept-I started satellites not because it was easy, but because it was hard, and at times still is! This was back in the days of the RS satellites. I believe if you present the challenge they will come. Unfortunately we need the money upfront not after the fact. Perhaps this incremental effort toward HEO or MEO is required, however we (AMSAT's) have been doing this for a long time and I think should have had our ducks lined up by now. We're a bunch of cleaver people and should develop a method getting the necessary funds for launches. Everything is now bottom line driven. We should just do it. 73 Bob W7LRD Seattle - Original Message - From: Paul Stoetzer n...@arrl.net To: Phil Karn k...@ka9q.net Cc: amsat-bb@amsat.org Sent: Saturday, July 19, 2014 12:28:12 PM Subject: Re: [amsat-bb] ANS-199 AMSAT News Service Special Bulletin - AMSAT Fox-1C Launch Opportunity Announced Are FM repeater satellites what we all want in orbit? No. Personally, I'd like a Mode J linear transponder in a sun synchronous circular orbit of about 2,000km (if we can't get anything to HEO). However, the Fox-1A, Fox-1B, Fox-1C, and Fox-1D satellites will eventually lead to the Fox-2 series of satellites. The software designed transponders on board the Fox-2 series will be capable of operating in any number of digital communications modes as well as operating as linear transponders. AO-51's V/U FM repeater was probably the most popular amateur satellite ever launched. Since the loss of AO-51, AMSAT-NA membership has been declining and is at the point where membership dues alone do not sustain the operating costs of the organization. Right now, those who are mildly interested in amateur satellites have one satellite to try with a minimal investment: SO-50, which is a satellite that for about half the days of each month is not convenient for most people who work 9-5 and sleep 10-6 and has a weak downlink that is often very difficult for newcomers to hear. Even experienced satellite operators are at times heard to transmit without being able to hear the satellite. With EO-80 (QB50p2), Fox-1A, and Fox-1C hopefully in orbit and operational next year, there will be three easily heard FM satellites (the 9 dB advantage of the 2m downlinks on these satellites will be quite welcome) - two in sun synchronous orbits with relatively consistent pass times. Having those satellites in orbit will mean that more hams get bitten by the satellite bug, join AMSAT, and progress to improving their stations to operate on the linear transponders and, potentially, on digital satellites. Bottom line - an AMSAT with more satellites in orbit means an AMSAT with more members and that's how we are eventually going to get our ideal satellites in orbit. 73, Paul, N8HM On Sat, Jul 19, 2014 at 2:54 PM, Phil Karn k...@ka9q.net wrote: On 07/18/2014 12:08 PM, Joseph Spier wrote: Fox-1C is the third of four Fox-1 series satellites under development, with Fox-1A and RadFXsat/Fox-1B launching through the NASA ELANA program. Fox-1C will carry an FM repeater system for amateur radio for use by radio hams and listeners worldwide. YET ANOTHER analog satellite? I'm not interested. ___ 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 ___ 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 ___ 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
Re: [amsat-bb] ANS-199 AMSAT News Service Special Bulletin - AMSAT Fox-1C Launch Opportunity Announced
Getting the $125,000 to launch a 1U cubesat into LEO should be plenty doable, but raising $10-$15 million for a launch to HEO? AMSAT-DL has been raising funds for P3E now for nearly a decade. If they thought they had a chance of success, I'm sure there'd be a much more public push to raise those funds. Unfortunately, there are not enough amateur radio operators interested in the amateur satellite program to put up that kind of money. Million dollar DXpeditions are doable because of the broad interest among the amateur radio community in funding those projects. A good number of amateur radio operators are only vaguely aware of the amateur satellite program and consider it to be quite esoteric. Heck, on the extremely rare occasion that the amateur satellite program merits a mention in a QST column these days, it's often in WB8IMY's Eclectic Technology column. That, unfortunately, shows you how the amateur radio community as a whole views the amateur satellite program. The bottom line is that AMSAT-NA needs a significant boost in membership and visibility and that boost needs to be soon. Putting two satellites into orbit that nearly every single ham will be able to easily hear (even a $30 Baofeng and it's stock duck should hear high passes of the Fox-1 satellites) along with the accompanying publicity should provide that boost. ARISSat-1 and the heavy publicity in QST and other amateur radio news sources is what got me involved in amateur satellites, though it would take me another two years before I really got into it seriously. Now I've really been bitten by the bug: 293 grids, 48 states, 4 Canadian provinces, and 27 DXCCs in my log plus I've done two public demonstrations of amateur satellites and assisted the AMSAT booth and demo station at Dayton. That's all because of a project derided by many on this board as a waste of AMSAT's time and resources! 73, Paul, N8HM On Sun, Jul 20, 2014 at 12:42 PM, Bob- W7LRD w7...@comcast.net wrote: a different slant-not wanting to enter the fm vs linear ongoing debate or the easy sat concept-I started satellites not because it was easy, but because it was hard, and at times still is! This was back in the days of the RS satellites. I believe if you present the challenge they will come. Unfortunately we need the money upfront not after the fact. Perhaps this incremental effort toward HEO or MEO is required, however we (AMSAT's) have been doing this for a long time and I think should have had our ducks lined up by now. We're a bunch of cleaver people and should develop a method getting the necessary funds for launches. Everything is now bottom line driven. We should just do it. 73 Bob W7LRD Seattle From: Paul Stoetzer n...@arrl.net To: Phil Karn k...@ka9q.net Cc: amsat-bb@amsat.org Sent: Saturday, July 19, 2014 12:28:12 PM Subject: Re: [amsat-bb] ANS-199 AMSAT News Service Special Bulletin - AMSAT Fox-1C Launch Opportunity Announced Are FM repeater satellites what we all want in orbit? No. Personally, I'd like a Mode J linear transponder in a sun synchronous circular orbit of about 2,000km (if we can't get anything to HEO). However, the Fox-1A, Fox-1B, Fox-1C, and Fox-1D satellites will eventually lead to the Fox-2 series of satellites. The software designed transponders on board the Fox-2 series will be capable of operating in any number of digital communications modes as well as operating as linear transponders. AO-51's V/U FM repeater was probably the most popular amateur satellite ever launched. Since the loss of AO-51, AMSAT-NA membership has been declining and is at the point where membership dues alone do not sustain the operating costs of the organization. Right now, those who are mildly interested in amateur satellites have one satellite to try with a minimal investment: SO-50, which is a satellite that for about half the days of each month is not convenient for most people who work 9-5 and sleep 10-6 and has a weak downlink that is often very difficult for newcomers to hear. Even experienced satellite operators are at times heard to transmit without being able to hear the satellite. With EO-80 (QB50p2), Fox-1A, and Fox-1C hopefully in orbit and operational next year, there will be three easily heard FM satellites (the 9 dB advantage of the 2m downlinks on these satellites will be quite welcome) - two in sun synchronous orbits with relatively consistent pass times. Having those satellites in orbit will mean that more hams get bitten by the satellite bug, join AMSAT, and progress to improving their stations to operate on the linear transponders and, potentially, on digital satellites. Bottom line - an AMSAT with more satellites in orbit means an AMSAT with more members and that's how we are eventually going to get our ideal satellites in orbit. 73, Paul, N8HM On Sat, Jul 19, 2014 at 2:54 PM, Phil Karn k...@ka9q.net wrote: On 07/18/2014 12:08 PM, Joseph
Re: [amsat-bb] ANS-199 AMSAT News Service Special Bulletin - AMSAT Fox-1C Launch Opportunity Announced
On 7/20/2014 12:00 PM, Paul Stoetzer wrote: IN PART The bottom line is that AMSAT-NA needs a significant boost in membership and visibility and that boost needs to be soon. I gave up on AMSAT when it seemed that the main afford was put into FM in and FM out satellites. Membership ran out many (15) years ago. John ___ 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
Re: [amsat-bb] ANS-199 AMSAT News Service Special Bulletin - AMSAT Fox-1C Launch Opportunity Announced
The Fox-1 series of satellites will lead to the Fox-2 series with many more interesting modes and capabilities. Yes, the priority is on building and launching the Fox-1 series, but a good portion of that work will be done by next year and then the lessons learned can be applied to constructing and launching the Fox-2 series. The reality is, of course, that FM satellites are extremely popular. I have read through much of the AMSAT-BB archives and I find a ton more posts about grid and country activations from back when AO-51 was alive than what you see now. Getting on the linear satellites is not expensive or complicated at all, but for whatever reason, we just have not been able to communicate that it's both fun, extremely rewarding, and that won't break the bank doing it to the amateur radio community as a whole, so for those of us who enjoy chasing grids, states, provinces, DX, etc, we do rely on the availability of FM satellites to activate those areas. Also remember that AMSAT is a membership organization. If members are not happy with the direction of the organization, they are free to select directors who prioritize what the membership desires. Non-members, however, have no voice in the proceedings. 73, Paul, N8HM On Sun, Jul 20, 2014 at 1:19 PM, John Becker w0...@big-river.net wrote: On 7/20/2014 12:00 PM, Paul Stoetzer wrote: IN PART The bottom line is that AMSAT-NA needs a significant boost in membership and visibility and that boost needs to be soon. I gave up on AMSAT when it seemed that the main afford was put into FM in and FM out satellites. Membership ran out many (15) years ago. John ___ 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 ___ 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
Re: [amsat-bb] ANS-199 AMSAT News Service Special Bulletin - AMSAT Fox-1C Launch Opportunity Announced
This is great news. I thank all the AMSAT volunteers, past and present for this opportunity. GO FOX, GO! 73 Clayton W5PFG On Jul 18, 2014 2:11 PM, Joseph Spier w...@vfr.net wrote: AMSAT NEWS SERVICE ANS-199 The AMSAT News Service bulletins are a free, weekly news and infor- mation service of AMSAT North America, The Radio Amateur Satellite Corporation. ANS publishes news related to Amateur Radio in Space including reports on the activities of a worldwide group of Amateur Radio operators who share an active interest in designing, building, launching and communicating through analog and digital Amateur Radio satellites. The news feed on http://www.amsat.org publishes news of Amateur Radio in Space as soon as our volunteers can post it. Please send any amateur satellite news or reports to: ans-editor at amsat.org. In this edition: * AMSAT Fox-1C Launch Opportunity Announced SB SAT @ AMSAT $ANS-199.01 ANS-199 AMSAT News Service Special Bulletin AMSAT News Service Bulletin 199.01 From AMSAT HQ KENSINGTON, MD. DATE July 18, 2014 To All RADIO AMATEURS BID: $ANS-199.01 - AMSAT Fox-1C Launch Opportunity Announced AMSAT is excited to announce a launch opportunity for the Fox-1C Cubesat. AMSAT has teamed with Spaceflight Inc. for integration and launch utilizing Spaceflight's SHERPA system to a sun-synchronous orbit in the third quarter of 2015. Fox-1C is the third of four Fox-1 series satellites under development, with Fox-1A and RadFXsat/Fox-1B launching through the NASA ELANA program. Fox-1C will carry an FM repeater system for amateur radio for use by radio hams and listeners worldwide. Further details on the satellite and launch will be made available as soon as released. AMSAT has an immediate need to raise funds to cover both the launch contract and additional materials for construction and testing for Fox-1C. We have set a fundraising goal of $125,000 dollars to cover these expenses over the next 12 months, and allow us to continue to keep amateur radio in space. Donations may be made through the AMSAT webpage at www.amsat.org, by calling (888) 322-6728 or by mail to the AMSAT office at 10605 Concord Street, Kensington, MD 20895, USA. Please consider a recurring, club, or corporate donation to maximize our chance of success with this mission. Also watch our website at www.amsat.org,follow us on Twitter at AMSAT, or on Facebook as The Radio Amateur Satellite Corporation for continuing news and opportunities for support. AMSAT is a 501(c)3 non-profit corporation and donations may be tax-deductible. [ANS Thanks AMSAT Board of Directors for the above information] - /EX In addition to regular membership, AMSAT offers membership in the President's Club. Members of the President's Club, as sustaining donors to AMSAT Project Funds, will be eligible to receive addi- tional benefits. Application forms are available from the AMSAT Office. Primary and secondary school students are eligible for membership at one-half the standard yearly rate. Post-secondary school students enrolled in at least half time status shall be eligible for the stu- dent rate for a maximum of 6 post-secondary years in this status. Contact Martha at the AMSAT Office for additional student membership information. 73, This week's ANS Editor, Joe Spier, K6WAO k6wao at amsat dot org ___ 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 ___ 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
Re: [amsat-bb] ANS-199 AMSAT News Service Special Bulletin -AMSAT Fox-1C Launch Opportunity Announced
I personally am going to ask my local Amateur Radio Club to throw a donation on the Fox 1C project. I challenge you to present the same request along to your own local clubs. I do numerous Radio Merit Badge presentations for the Boy Scouts and one of the things I love to do is to throw in a satellite contact opportunity. Yes linear passes are fun and very capable, but the concept of showing them that this kind of technology is available and doable with just a simple hand held radio and an antenna that you can hold in your hand is much more in the realm of I could do this too if I had an Amateur Radio license feeling. Right now, we only one FM bird up there that can be counted on, SO-50, Fox 1A and 1B are still a year off. (Lituanicasat-1 will be decaying within days, and maybe two if the French FM satellite opens up soon). Thus the opportunities for these basic but, Oh for the Scouts, downright exciting communication events is quite limited. The AO-27 contact we did in one of those Radio Merit Badge workshops (Before it died), sealed the deal for a Scout and his dad who were attending and they both ended up getting their tickets. You can wow them with big ticket equipment and complexity (Smoke and mirrors), but fun and excitement will get them hooked. Often times, simple is better. An additional challenge for the HEO, MEO and Linear or nothing folks out there is, instead of buying the next accessory for your already ample station, give a donation to the FOX project (Or other national AMSAT-esque project, FM, Linear or Digital), and let's get the ball rolling on many new opportunities out there just waiting. You donation may help get another Scout/young person hooked on our aspect of the hobby. Tom Schuessler, N5HYP ___ 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
Re: [amsat-bb] ANS-199 AMSAT News Service Special Bulletin - AMSAT Fox-1C Launch Opportunity Announced
Yes, that is exactly the temperatures of PCSAT in similar eclipse periods. IE, anything more or less uniformly BLACK (solar panels) no matter the shape and size will assume that average temperature with 35% eclipses. This is because the absorbtivity and emissivity of black are both 0.9. (assuming there is some thermal communication within the spacecraft to move the heat evenly (such as an aluminum frame)... If it ever gets into a 0% eclipse period (full sun) those average temps will rise to about 30-40C. Still safe for most electronics. Bob, WB4APR On Sun, Jul 20, 2014 at 11:09 AM, Graham Shirville g.shirvi...@btinternet.com wrote: Hi Phil, The reality is, even with no battery heater on FUNcube-1 we seem to have an acceptable battery temperature of between 0 and +5C. The temp sensor is, of course, actually external to the battery itself. Our orbit is sun synchronous so we suffer eclipses for approx 33% of the orbit ..but then we are relatively close to the earth! I would also comment that any active attitude control system will consume power...which we don't have much of.. Probably, if you need continuous operation of the radio system, then a 2U with deployable solar panels is the minimum configuration for a CubeSat operating on microwave bands with an active attitude control system. best 73 Graham G3VZV -Original Message- From: g0...@aol.com Sent: Sunday, July 20, 2014 3:41 PM To: k...@ka9q.net ; amsat-bb@amsat.org ; bruni...@usna.edu Subject: Re: [amsat-bb] ANS-199 AMSAT News Service Special Bulletin - AMSAT Fox-1C Launch Opportunity Announced I must quickly point out some real data: www.warehouse.funcube.org.uk Which shows an equilibrium of around +20 degrees after 64 minutes of sunlight. Black solar cells on a black surface but some polished Aluminium in the structure. During eclipse, The Earth facing side begins to increase in temperature at around -16 degrees, but then cools down rapidly as the cube rotates. The temperature is still heading down rapidly as it exits eclipse after 34 minutes and at around -24C on the outside surfaces. Thanks David -Original Message- From: Phil Karn k...@ka9q.net To: amsat-bb amsat-bb@amsat.org Sent: Sun, 20 Jul 2014 11:59 Subject: Re: [amsat-bb] ANS-199 AMSAT News Service Special Bulletin - AMSAT Fox-1C Launch Opportunity Announced On 07/19/2014 09:23 PM, Robert Bruninga wrote: I cannot believe that. The equilibrium of a nominally black (solar panels on all sides) spacecraft is something like about 0 to 30 C (32F to 90F) a very benign operational range. The only time you DO have thermal issues is when you DO have attitude control and have things that are not equally over time seeing the sun and dark sky. See Dick's paper for the details; I'm just quoting his results. I know the basic physics of heat transfer in space but I would never call myself an expert. He is. But I can do a back-of-the-envelope calculation that tells me he's right. The solar cells they're using have an absorptivity and emissivity that is both 0.98, as I recall, so a cubesat covered with them is essentially a perfect blackbody. A blackbody cube with one face normal to the sun at 1 AU will reach an equilibrium temperature of -21.35 C. The problem is that the ratio of radiating area to absorbing area for a cube is 6:1 (with the sun normal to one surface). A sphere would be warmer because its ratio of radiating to absorbing area is only 4:1. A thin flat plate normal to the sun (like a solar wing) would be even warmer -- 2:1. And that -21.35 C figure is for continuous sunlight. Throw in eclipses and things get much worse. Yes, it would be a little better when the sun shines on a corner rather than normal to a face, and Earth albedo and IR radiation will warm things a little, but not enough to matter. --Phil PS: Temperature of 10 cm blackbody cube at 1 AU: Area facing sun: .01 m^2 Solar constant: 1367.5 W/m^2 Absorbed power = 13.675 W Total radiating area: .06 m^2 Emissivity = 1.0 (perfect blackbody) Stefan-Boltzmann constant = 5.6703e-8 W/(m^2K^4) T = (13.675 W / (5.6703e-8 * 1.0 * .06)) ** (1/4) = 251.8K == -21.35 C ___ 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 ___ 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 ___ 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
Re: [amsat-bb] ANS-199 AMSAT News Service Special Bulletin - AMSAT Fox-1C Launch Opportunity Announced
Thanks for the FOX-1 thermal data! (36 C variation per orbit) PCSAT (10 cubesat) has less than 15C variation on its sides with its 0.6 RPM spin and 35% eclipses, but this is because the sides are made of 1/8 aluminum and have a huge 1/8 center deck that is thermally connected to the center of each face, providing great communication from the sun side to the other sides. Notice, this was a HEAVY satellite because we just overbuilt it to make sure the heat was evenly distributed. On Sun, Jul 20, 2014 at 10:41 AM, g0...@aol.com wrote: I must quickly point out some real data: www.warehouse.funcube.org.uk Which shows an equilibrium of around +20 degrees after 64 minutes of sunlight. Black solar cells on a black surface but some polished Aluminium in the structure. During eclipse, The Earth facing side begins to increase in temperature at around -16 degrees, but then cools down rapidly as the cube rotates. The temperature is still heading down rapidly as it exits eclipse after 34 minutes and at around -24C on the outside surfaces. Thanks David -Original Message- From: Phil Karn k...@ka9q.net To: amsat-bb amsat-bb@amsat.org Sent: Sun, 20 Jul 2014 11:59 Subject: Re: [amsat-bb] ANS-199 AMSAT News Service Special Bulletin - AMSAT Fox-1C Launch Opportunity Announced On 07/19/2014 09:23 PM, Robert Bruninga wrote: I cannot believe that. The equilibrium of a nominally black (solar panels on all sides) spacecraft is something like about 0 to 30 C (32F to 90F) a very benign operational range. The only time you DO have thermal issues is when you DO have attitude control and have things that are not equally over time seeing the sun and dark sky. See Dick's paper for the details; I'm just quoting his results. I know the basic physics of heat transfer in space but I would never call myself an expert. He is. But I can do a back-of-the-envelope calculation that tells me he's right. The solar cells they're using have an absorptivity and emissivity that is both 0.98, as I recall, so a cubesat covered with them is essentially a perfect blackbody. A blackbody cube with one face normal to the sun at 1 AU will reach an equilibrium temperature of -21.35 C. The problem is that the ratio of radiating area to absorbing area for a cube is 6:1 (with the sun normal to one surface). A sphere would be warmer because its ratio of radiating to absorbing area is only 4:1. A thin flat plate normal to the sun (like a solar wing) would be even warmer -- 2:1. And that -21.35 C figure is for continuous sunlight. Throw in eclipses and things get much worse. Yes, it would be a little better when the sun shines on a corner rather than normal to a face, and Earth albedo and IR radiation will warm things a little, but not enough to matter. --Phil PS: Temperature of 10 cm blackbody cube at 1 AU: Area facing sun: .01 m^2 Solar constant: 1367.5 W/m^2 Absorbed power = 13.675 W Total radiating area: .06 m^2 Emissivity = 1.0 (perfect blackbody) Stefan-Boltzmann constant = 5.6703e-8 W/(m^2K^4) T = (13.675 W / (5.6703e-8 * 1.0 * .06)) ** (1/4) = 251.8K == -21.35 C ___ 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 ___ 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
Re: [amsat-bb] ANS-199 AMSAT News Service Special Bulletin - AMSAT Fox-1C Launch Opportunity Announced
Hummh, We get an equilibrium of a cube to be about 55F (13C) when exposed to the sun on one side and all the other sides radiating to cold space. (assuming they are thermally connected). I wonder why the big difference between our calculations? Bob, WB4aPR On Sun, Jul 20, 2014 at 6:59 AM, Phil Karn k...@ka9q.net wrote: On 07/19/2014 09:23 PM, Robert Bruninga wrote: I cannot believe that. The equilibrium of a nominally black (solar panels on all sides) spacecraft is something like about 0 to 30 C (32F to 90F) a very benign operational range. The only time you DO have thermal issues is when you DO have attitude control and have things that are not equally over time seeing the sun and dark sky. See Dick's paper for the details; I'm just quoting his results. I know the basic physics of heat transfer in space but I would never call myself an expert. He is. But I can do a back-of-the-envelope calculation that tells me he's right. The solar cells they're using have an absorptivity and emissivity that is both 0.98, as I recall, so a cubesat covered with them is essentially a perfect blackbody. A blackbody cube with one face normal to the sun at 1 AU will reach an equilibrium temperature of -21.35 C. The problem is that the ratio of radiating area to absorbing area for a cube is 6:1 (with the sun normal to one surface). A sphere would be warmer because its ratio of radiating to absorbing area is only 4:1. A thin flat plate normal to the sun (like a solar wing) would be even warmer -- 2:1. And that -21.35 C figure is for continuous sunlight. Throw in eclipses and things get much worse. Yes, it would be a little better when the sun shines on a corner rather than normal to a face, and Earth albedo and IR radiation will warm things a little, but not enough to matter. --Phil PS: Temperature of 10 cm blackbody cube at 1 AU: Area facing sun: .01 m^2 Solar constant: 1367.5 W/m^2 Absorbed power = 13.675 W Total radiating area: .06 m^2 Emissivity = 1.0 (perfect blackbody) Stefan-Boltzmann constant = 5.6703e-8 W/(m^2K^4) T = (13.675 W / (5.6703e-8 * 1.0 * .06)) ** (1/4) = 251.8K == -21.35 C ___ 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 ___ 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
Re: [amsat-bb] ANS-199 AMSAT News Service Special Bulletin - AMSAT Fox-1C Launch Opportunity Announced
On 07/19/2014 09:23 PM, Robert Bruninga wrote: Yes, but with who? 95% of everyone in view is more than 45 degrees OUT of the main beam. Directional antennas have zero value on LEO birds that need to serve everyone in view at the same time. And if you only serve those in the main beam, then the duration is under 1 minute. Run the link budgets. With reasonable numbers (transmit power 100 mW, range 1,000 km, Rx T = 50K) you only need a few dB of transmit gain to get megabits/sec into a 60 cm DBS dish at 10 GHz. A few dB can easily cover an entire hemisphere, though you might want to squash the pattern to cover it more uniformly (as the GPS satellites do). The big reason to use attitude control isn't high on-axis antenna gain, it's AVOIDING ANTENNA NULLS. Fading was the major factor in every one of the modulation/coding schemes I've designed for AMSAT. It forces me to use noncoherent (DBPSK) modulation, which even with FEC can cost as much as 4-5dB over coherent BPSK. And that's WITHOUT fading. Fading is a major headache in coding design because you need to know how long a fade will last to know how long to make your interleaver, and you simply don't know when the spacecraft is unstabilized. At least I had a good idea with AO-40 because the fading was caused by the spacecraft spin so it was quite predictable. But ARISSat-1 was completely unstabilized and I didn't even have an antenna pattern, so I basically had to pull a maximum fade duration out of my butt. Same with FOX-1, although it's somewhat less severe in the data-under-voice mode since it's the fade duration relative to the data rate that matters, and the data rate in that mode is so extremely low. But it's a serious problem in the high speed (data only) mode. And for truly interesting data rates (hundreds of kilobits/sec and up), slow fading is simply intolerable. Attitude stabilized antennas are the only way. --Phil ___ 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
Re: [amsat-bb] ANS-199 AMSAT News Service Special Bulletin - AMSAT Fox-1C Launch Opportunity Announced
On 07/20/2014 06:27 AM, Rick Walter wrote: I was not going to post but since no one else has, I thought there needs to be a correction to a statement made in case some younger people are reading the thread. Phil said: Good analogy, actually. They returned to the moon six times (succeeding on five) because they had excess hardware originally built in the expectation that the first attempts would fail. There were actually seven manned missions to the moon. Six succeeded. Apollo 13 never landed on the moon and returned to earth safely. Apollo 11,12,14,15,16, and 17 landed. 12 American astronauts walked on the moon. That's exactly what I said. They *returned* to the moon (i.e., after landing the first time on Apollo 11) six times, succeeding on five. Three missions went to the moon without landing: Apollos 8, 10 and 13, for a total of nine Apollo lunar missions. Two more (7 9) remained in earth orbit. --Phil ___ 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
Re: [amsat-bb] ANS-199 AMSAT News Service Special Bulletin - AMSAT Fox-1C Launch Opportunity Announced
On 07/20/2014 08:09 AM, Graham Shirville wrote: Hi Phil, The reality is, even with no battery heater on FUNcube-1 we seem to have an acceptable battery temperature of between 0 and +5C. The temp sensor is, of course, actually external to the battery itself. You must be using different solar cells, or perhaps you don't fully cover the exterior with them. I did wonder why Dick didn't consider the same thing for Fox-1; if you're going to dissipate some of the electricity they generate in resistance heaters, you might consider covering less than 100% of the surface with them and cover the remainder with thermal blankets. I haven't worked out this alternative, and as I said I'm not a thermal design expert. At the time I believe Dick said he was considering gold plating the inside surfaces of the cells to isolate them from the interior, since there was little or no room for any other kind of insulation. In that case you would no longer have thermal equilibrium and my back of the envelope calculation would not apply. There's one additional factor to make things worse, though I haven't quantified it. Space-rated solar cells are getting good enough that the spacecraft as a whole actually converts a non-insignificant amount of the sunlight hitting it into transmitted RF, and that power is no longer available to keep the spacecraft warm. So it gets even colder. That's right, turn on the transmitter and the spacecraft cools down -- at least if the solar cells are not thermally isolated from the interior. Our orbit is sun synchronous so we suffer eclipses for approx 33% of the orbit ..but then we are relatively close to the earth! Yes, and you do pick up longwave IR from the earth even on the night side. According to my copy of Spacecraft Thermal Control Handbook Vol 1, this is only about 150 W/m^2 in LEO, so it doesn't seem to help that much. Albedo is greater (about 250 W/m^2) but only over the subsolar point so again it doesn't help much on average. It *would* help a lot if you could insulate those sides facing dark sky, and that's where attitude control comes in. During his after-dinner talk at the AMSAT Symposium a couple of years ago, astronaut Sam Durrance described just how cold that dark sky is. He flew with Ron Parise on the Astro-1 and -2 shuttle missions. Because these were astronomy missions, the shuttle payload bay spent long periods pointed at dark sky, as opposed to its usual practice (when not docked to the ISS) of keeping the payload bay toward earth. He said it got so cold near the orbiter's overhead windows that they had to don sweaters. But the real issue that Dick drove home to me in his talk was just how variable the thermal situation was when you can't control your attitude and when eclipse durations and beta angles vary so drastically over a year. Even if you could design for acceptable equilibrium temperatures under one set of conditions you can't maintain them as they vary so much. I would also comment that any active attitude control system will consume power...which we don't have much of.. Yes, but active attitude control lets you keep those panels pointed at the sun to produce much more power on average. Only two of the six surfaces of a 1U cubesat even need solar cells with my stabilized design. You can do much better with deployable, steerable panels -- which pretty much demands active attitude control. The fact that virtually every military, commercial and scientific spacecraft launched today is three-axis stabilized should settle the question: active attitude control is the way to go, if you can do it. --Phil ___ 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
Re: [amsat-bb] ANS-199 AMSAT News Service Special Bulletin - AMSAT Fox-1C Launch Opportunity Announced
On 07/20/2014 10:00 AM, Paul Stoetzer wrote: A good number of amateur radio operators are only vaguely aware of the amateur satellite program and consider it to be quite esoteric. Precisely. Huge az/el yagi arrays don't help that image either. Nor does an occasional, brief, noisy pass of an FM voice-only satellite carrying 1 QSO at a time do much to impress a young person with a mobile phone in his pocket that he can use to talk or message anywhere in the world. The term easysat doesn't seem appropriate when said FM voice satellite requires pointing an ungainly-looking 2m antenna at the sky even if that antenna is very small by usual ham satellite standards. Most mobile phones don't even have visible external antennas anymore. I'm not trying to make ham radio into a utility to compete with either the Internet or mobile phones. That's not what it's for. But for those who'd like to learn, hands-on, about modern communication technology -- for which ham radio *IS* still uniquely suited -- you have to offer something that's actually halfway modern! I can't do anything about the occasional, brief passes of a LEO without going to a higher altitude orbit. But I certainly *can* do far better with a LEO satellite and a ~1/2 meter ground antenna by: 1. Adding 3-axis attitude control to the spacecraft. 2. Moving up to the microwave bands. 3. Going digital. Instead of one voice conversation (interrupted by deep, noisy fades) you could support many. Although the LEO passes would still be occasional and brief, alternatives to real-time voice would be available. Bulk data (including recorded and possibly lengthy voice messages) could be sent up and delivered to an entirely different part of the globe. For those who don't really care to talk, satellite-generated data (e.g., telemetry, imagery) can be multiplexed with the downlink data. The bottom line is that AMSAT-NA needs a significant boost in membership and visibility and that boost needs to be soon. Putting two satellites into orbit that nearly every single ham will be able to easily hear (even a $30 Baofeng and it's stock duck should hear high passes of the Fox-1 satellites) along with the accompanying publicity should provide that boost. Suppose it were just as easy and cheap to build or buy an amateur digital microwave satellite earth terminal? In this age of mobile microprocessors that would at one time have been considered supercomputers; handheld GPS receivers; Sirius/XM receivers with postage-stamp antennas; and direct broadcast satellite dishes -- just to mention a few now-widespread consumer items -- do you really think it so impossible to set our sights as hams just a little higher than 1960s technology? --Phil ___ 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
Re: [amsat-bb] ANS-199 AMSAT News Service Special Bulletin - AMSAT Fox-1C Launch Opportunity Announced
On 07/18/2014 12:08 PM, Joseph Spier wrote: Fox-1C is the third of four Fox-1 series satellites under development, with Fox-1A and RadFXsat/Fox-1B launching through the NASA ELANA program. Fox-1C will carry an FM repeater system for amateur radio for use by radio hams and listeners worldwide. YET ANOTHER analog satellite? I'm not interested. ___ 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
Re: [amsat-bb] ANS-199 AMSAT News Service Special Bulletin - AMSAT Fox-1C Launch Opportunity Announced
Are FM repeater satellites what we all want in orbit? No. Personally, I'd like a Mode J linear transponder in a sun synchronous circular orbit of about 2,000km (if we can't get anything to HEO). However, the Fox-1A, Fox-1B, Fox-1C, and Fox-1D satellites will eventually lead to the Fox-2 series of satellites. The software designed transponders on board the Fox-2 series will be capable of operating in any number of digital communications modes as well as operating as linear transponders. AO-51's V/U FM repeater was probably the most popular amateur satellite ever launched. Since the loss of AO-51, AMSAT-NA membership has been declining and is at the point where membership dues alone do not sustain the operating costs of the organization. Right now, those who are mildly interested in amateur satellites have one satellite to try with a minimal investment: SO-50, which is a satellite that for about half the days of each month is not convenient for most people who work 9-5 and sleep 10-6 and has a weak downlink that is often very difficult for newcomers to hear. Even experienced satellite operators are at times heard to transmit without being able to hear the satellite. With EO-80 (QB50p2), Fox-1A, and Fox-1C hopefully in orbit and operational next year, there will be three easily heard FM satellites (the 9 dB advantage of the 2m downlinks on these satellites will be quite welcome) - two in sun synchronous orbits with relatively consistent pass times. Having those satellites in orbit will mean that more hams get bitten by the satellite bug, join AMSAT, and progress to improving their stations to operate on the linear transponders and, potentially, on digital satellites. Bottom line - an AMSAT with more satellites in orbit means an AMSAT with more members and that's how we are eventually going to get our ideal satellites in orbit. 73, Paul, N8HM On Sat, Jul 19, 2014 at 2:54 PM, Phil Karn k...@ka9q.net wrote: On 07/18/2014 12:08 PM, Joseph Spier wrote: Fox-1C is the third of four Fox-1 series satellites under development, with Fox-1A and RadFXsat/Fox-1B launching through the NASA ELANA program. Fox-1C will carry an FM repeater system for amateur radio for use by radio hams and listeners worldwide. YET ANOTHER analog satellite? I'm not interested. ___ 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 ___ 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
Re: [amsat-bb] ANS-199 AMSAT News Service Special Bulletin - AMSAT Fox-1C Launch Opportunity Announced
On 07/19/2014 12:28 PM, Paul Stoetzer wrote: Are FM repeater satellites what we all want in orbit? No. Personally, I'd like a Mode J linear transponder in a sun synchronous circular orbit of about 2,000km (if we can't get anything to HEO). Getting a launch opportunity is difficult and expensive. Going digital is not. However, the Fox-1A, Fox-1B, Fox-1C, and Fox-1D satellites will eventually lead to the Fox-2 series of satellites. I've been hearing that for years, so please forgive my skepticism. Tony AA2TX himself told me that the analog Fox-1 would be followed by the digital Fox-2. Now we have Fox-1B, Fox-1C, etc, that will also be analog. Forgive me if I feel a little like Achilles racing the tortoise. I originally joined AMSAT as a technical volunteer in mid 1980, shortly after the Phase III-A launch failure. At the time, AMSAT was doing some very impressive things. Many weren't even being done (or were just starting to be done) in the commercial world: the use of digital command and telemetry links, the use of onboard computers, even the use of ground computers to steer antennas. AMSAT had shown how to locate an emergency beacon by measuring its Doppler shift through a LEO transponder -- which eventually became the SARSAT (Search and Rescue Satellite) payload on many US and Russian LEO weather satellites. And AMSAT was showing how to do it all on a low budget, with resourcefulness replacing brute force bucks. I was blown away by clever little tricks like spinning a satellite by painting one side of its antennas black and the other side white. This was ham radio at its best. But that was 1980. It's now 34 years later and we're still doing the same old thing. Meanwhile, mobile phones and the Internet have gone from the exotic to the commonplace -- and I don't have to tell you that they're 100% digital. TV broadcasting is also now digital, few cable TV systems still carry analog signals, and FM and shortwave broadcasting are in a digital transition. When AMSAT showed how to use an inexpensive hand-held radio to communicate with a satellite, no one had ever seen such a thing. Now digital satellite broadcasting and GPS are nearly universal in cars, hikers and boaters carry SPOT units, and you can buy handheld Iridium phones that will work anywhere on the globe. All digital, of course. Yet AMSAT continues to fly one analog satellite after another. Why? All these outside developments have rendered FCC Part 97.1, the Basis and Purpose of the Amateur Service, almost completely obsolete with the singular exception of personal technical education and possibly (some) emergency communications. You want to further international goodwill by talking to people in other countries? Get on the Internet. You want to call your wife to see if she needs anything? Pick up your mobile phone. Further the technical art? Go work for a communications RD company, because it isn't happening in ham radio anymore. How are we justifying our spectrum by doing the same thing over and over again, while the world passes us by? Appealing to what the members want doesn't fly with me, because the members are a tiny fraction of our potential audience. AMSAT keeps wondering why it can't seem to grow beyond a tiny niche; it need look no further for the reason. Nor does an appeal to simplicity and cost carry any weight. Mobile phones, GPS units and Sirius/XM receivers may not be simple but that doesn't keep them from being cheap and easy to use. It's their very complexity (if you consider digital to be complex -- which I don't) that makes them cheap and easy to use. But by design they are impossible to take apart and learn from. That's where the amateur service can still play a big role. For those who want to learn communications technology by hands-on experimentation there is still simply nothing like it. But where are the amateur digital voice satellite systems to take apart and study? At least a linear transponder could repeat an efficient digital signal, but with the trend to FM even that is no longer possible. If an amateur satellite carries any digital links at all, they are slow and generally limited to telemetry and command, not user-to-user communications. Many don't even use modern modulation and error-correction methods, making them that much harder to access with the small antennas to which most hams are now limited because of CCRs and other restrictions. Far from being elitist or hard to use, digital represents the *only* way forward. It's time to move into the 21st century. --Phil ___ 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
Re: [amsat-bb] ANS-199 AMSAT News Service Special Bulletin - AMSAT Fox-1C Launch Opportunity Announced
Getting a launch opportunity is difficult and expensive. Going digital is not. The Fox satellites each have four designated experiment cards. Assemble a team and pitch a proposal for 1D, or 1C if you can do it in a hurry. 73, Drew KO4MA ___ 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
Re: [amsat-bb] ANS-199 AMSAT News Service Special Bulletin - AMSAT Fox-1C Launch Opportunity Announced
On 7/19/2014 1:54 PM, it was wrote: YET ANOTHER analog satellite? I'm not interested. I hear yeah ! ___ 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
Re: [amsat-bb] ANS-199 AMSAT News Service Special Bulletin - AMSAT Fox-1C Launch Opportunity Announced
On 7/19/2014 3:24 PM, Phil Karn wrote: However, the Fox-1A, Fox-1B, Fox-1C, and Fox-1D satellites will eventually lead to the Fox-2 series of satellites. I've been hearing that for years, so please forgive my skepticism. Tony AA2TX himself told me that the analog Fox-1 would be followed by the digital Fox-2. Now we have Fox-1B, Fox-1C, etc, that will also be analog. Forgive me if I feel a little like Achilles racing the tortoise. Ah, but the plan always was to build four of the Fox-1 series, which is a series of FM analog transponders. Initially, one had a launch and the other three would be ready to fly if other opportunities came up. If you're going to spend the time developing them, why not partner for free launches (ELaNa) for more than one? The opportunities for an FM transponder and educational outreach are good. I still have universities looking to partner. Look at it this way... we are clearing the shelves with 3 out of 4 of the intended Fox-1 going to orbit, that really means that we can pretty much call it a day with Fox-1 and move on to Fox-2 now. We will build them all and be done with them all by next May. There will be more than one flying soon, so that we can learn how well they work and apply those lessons to Fox-2 while we're working out the design. It's only the beginning! Jerry Buxton, NØJY ___ 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
Re: [amsat-bb] ANS-199 AMSAT News Service Special Bulletin - AMSAT Fox-1C Launch Opportunity Announced
Hey, this sounds like a terrific opportunity. Not only did AMSAT work on securing our new launch opportunities ... but we are in a position to offer a launch opportunity for a mode/radio/experiment for those who can contribute to amateur radio in space instead of complain about it. -- 73 de JoAnne K9JKM k9...@amsat.org -Original Message- From: amsat-bb-boun...@amsat.org [mailto:amsat-bb-boun...@amsat.org] On Behalf Of Andrew Glasbrenner Sent: Saturday, July 19, 2014 15:43 To: 'Phil Karn'; 'Paul Stoetzer' Cc: amsat-bb@amsat.org Subject: Re: [amsat-bb] ANS-199 AMSAT News Service Special Bulletin - AMSAT Fox-1C Launch Opportunity Announced Getting a launch opportunity is difficult and expensive. Going digital is not. The Fox satellites each have four designated experiment cards. Assemble a team and pitch a proposal for 1D, or 1C if you can do it in a hurry. 73, Drew KO4MA ___ 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 ___ 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
Re: [amsat-bb] ANS-199 AMSAT News Service Special Bulletin - AMSAT Fox-1C Launch Opportunity Announced
On 07/19/2014 01:42 PM, Andrew Glasbrenner wrote: Getting a launch opportunity is difficult and expensive. Going digital is not. The Fox satellites each have four designated experiment cards. Assemble a team and pitch a proposal for 1D, or 1C if you can do it in a hurry. 73, Drew KO4MA I see no reason to consider a digital satellite an experiment. Not in 2014, anyway. Besides, there are several other critical technical hurdles AMSAT must first overcome if we are to do anything interesting with a cubesat. First and foremost among them is ATTITUDE CONTROL! Passive bar magnets (or nothing at all, as on ARISSat-1) no longer cut it. The lack of attitude control forces us to use simple omnidirectional antennas, which in turn keeps us on the crowded and narrow VHF/UHF bands. Worse, there's really no such thing as an omnidirectional antenna so our links are plagued by frequent deep fades of unlimited (or at least unknown) duration. Fading has driven every one of my modulation/coding designs for AMSAT telemetry links -- at the expense of making them much less power-efficient. And power efficient means smaller ground antennas, and that means a cheaper and more accessible ground station for the average ham. And THAT means a much larger potential AMSAT membership. With attitude control, our satellite could use directional antennas on the microwave bands. Directional antennas on higher frequencies mean much better link budgets. You could easily do MEGABITS PER SECOND between LEO and small ground antennas! A lack of attitude control also plagues thermal design. I learned this from Dick Janssen KD1K's talk at the Symposium a few years ago when he said Fox-1 was the most difficult thermal design he'd ever done for AMSAT. And he's done many. The problem is that without attitude control you have to cover every available surface with solar cells to guarantee power in any attitude, and solar cells are excellent thermal radiators. Those not facing the earth or the sun face dark sky, radiating away much of the spacecraft's heat. I think he found the equilibrium temperature of a 1U cubesat to be something like -30 or -40 C! The team had no choice but to add resistance heaters to keep the payload (especially the batteries) warm. I can't think of a more painful use of scarce, hard-earned, expensive DC power in space. Attitude control would completely solve this problem too. In LEO the most common form of attitude control is local vertical/local horizontal, the mode the ISS uses most of the time. You'd designate one face as nadir-pointing; here you would mount antennas and earth observation cameras. With circularly polarized antennas, you'd still have a degree of freedom around the yaw axis, i.e., you could rotate around the local vertical with no effect on the RF links. The opposite (zenith-facing) side would have a solar cell, as would one of the four remaining sides. The remaining three would be covered with thermal blankets to insulate the spacecraft from the dark sky they'd face all the time. (Not being a thermal designer I haven't calculated what the new equilibrium temperature would be. But it would obviously solve Dick's problem. He might even have to leave part of those surfaces exposed to radiate excess heat!) You see how this works? At low beta angles, when the sun is in or near the orbital plane, you point the side with the solar cell forward at local sunrise. At local noon you yaw 180 degrees so the cell faces the sun as it sets behind you. At higher beta angles you simply yaw to track the sun as it passes off to one side; in the limiting case of a beta angle of 90 degrees (continuous sunlight) you'd simply keep the spacecraft yawed at a constant +90 or -90 degrees. And you only need to buy two expensive solar cells instead of (nearly) six. Attitude control systems for cubesats already exist. You can buy one for $200,000 from suppliers serving the burgeoning cubesat community (most of which considers ham radio completely irrelevant except as a source of free spectrum). But that's not the AMSAT way. I am sure that if we brought enough clever minds together (along with some good mechanical engineers and craftsmen) we could design and build our own attitude control system for far less. But to attract all those people to do all these new (in AMSAT) things, you have to stop doing the same old thing over and over. You have to make a conscious choice to stand back and actually innovate at the systems level instead of relegating digital to the status of an experiment on the same old primitive spacecraft bus. Look at all the attention and excitement generated by the ISEE-3 Reboot project. That's because they're actually doing something new and challenging. They say they've gotten donations from many people far outside the usual space groupie segment of the population. It's also caught the imagination of at least a few hams, including the AMSAT-DL gang which has been using their 20m Bochum dish to
Re: [amsat-bb] ANS-199 AMSAT News Service Special Bulletin - AMSAT Fox-1C Launch Opportunity Announced
On 07/19/2014 02:04 PM, Jerry Buxton wrote: other three would be ready to fly if other opportunities came up. If you're going to spend the time developing them, why not partner for free launches (ELaNa) for more than one? The opportunities for an FM transponder and educational outreach are good. I still have universities looking to partner. Ah, because launches are scarce and expensive, and (re)developing even the same old thing consumes much of AMSAT's limited resources. And they're limited because we have yet to interest more than a tiny niche in what we're doing. It's great to have universities looking to partner, but what do they bring to the table, really? Are we sure they're not just looking for free spectrum? one flying soon, so that we can learn how well they work and apply those lessons to Fox-2 while we're working out the design. We already know how well they'll work because we've done the same thing many times before. I hate to say it, but this is no longer rocket science. The physics is well understood, and those same physics tell us how we could accomplish so much more with our (currently) limited resources. --Phil ___ 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
Re: [amsat-bb] ANS-199 AMSAT News Service Special Bulletin - AMSAT Fox-1C Launch Opportunity Announced
On 7/19/2014 4:50 PM, Phil Karn wrote: Ah, because launches are scarce and expensive, and (re)developing even the same old thing consumes much of AMSAT's limited resources. And they're limited because we have yet to interest more than a tiny niche in what we're doing. But you arguing about something that has already happened. That makes no sense. Arguing for doing something different, as you also did just a bit ago today, makes sense. Why did the U.S. go back to the moon so many times? I don't know. But we did, and that is done. You could argue now that it had been done before, why did we do it over and over, it was the same old thing. That doesn't change the facts. There is an audience for these FM satellites. It's great to have universities looking to partner, but what do they bring to the table, really? Are we sure they're not just looking for free spectrum? Both universities that I am working with are building amateur radio ground stations and interesting the students in becoming hams. We all benefit from that. And some other universities want to fly an ADAC system. We may benefit from that on Fox-2. one flying soon, so that we can learn how well they work and apply those lessons to Fox-2 while we're working out the design. We already know how well they'll work because we've done the same thing many times before. I hate to say it, but this is no longer rocket science. The physics is well understood, and those same physics tell us how we could accomplish so much more with our (currently) limited resources. We have already learned a great deal from an engineering process perspective, as well as about cramming a lot into a little cubesat. Not rocket science, but certainly for a large all volunteer group a valuable step toward what it will take to build something more complex. I think you over estimate the ability of an all-volunteer workforce, in terms of churning out satellites akin to how a business does it. Amateur radio is a hobby! You see lemons. I see lemonade. But by all means, let's go for pink lemonade and keep on talking about Fox-2 opportunities while people enjoy what we have already done with the Fox-1 series! Jerry Buxton, NØJY ___ 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
Re: [amsat-bb] ANS-199 AMSAT News Service Special Bulletin - AMSAT Fox-1C Launch Opportunity Announced
On 07/19/2014 03:32 PM, Jerry Buxton wrote: But you arguing about something that has already happened. That makes no sense. None of the Fox satellites have yet flown, so they haven't already happened. Why did the U.S. go back to the moon so many times? I don't know. But we did, and that is done. You could argue now that it had been done before, why did we do it over and over, it was the same old thing. That doesn't change the facts. Good analogy, actually. They returned to the moon six times (succeeding on five) because they had excess hardware originally built in the expectation that the first attempts would fail. And when they did return, they began to do some serious scientific exploration that made it worthwhile. Unfortunately, the public *did* see this as the same old thing and Congress quickly withdrew support. As everyone knows, NASA canceled the last three Apollo lunar missions and humans haven't left earth orbit since Apollo 17. (Strictly speaking, even Apollo never left earth orbit, since the moon orbits the earth.) Yet NASA has always managed to find support for new and interesting things in space even without a human presence. The two keys to public interest have always been 1) exploration and 2) photography. Apollo certainly did that in its time. More recently, stunning pictures from the surface of Mars and of the moons and backlit rings of Saturn have done much to keep NASA going even as it flails aimlessly in its human program. Sure, the ISS returns some pretty good pictures of earth but so do many robotic spacecraft. And the ISS certainly isn't exploring much of space from only 400 km up. That's why most people don't find it very exciting. Both universities that I am working with are building amateur radio ground stations and interesting the students in becoming hams. We all benefit from that. And some other universities want to fly an ADAC system. We may benefit from that on Fox-2. I'm hearing privately that many university groups really are after us for only our spectrum. Or our spectrum plus a ready-made telecommunications system they can use for their purposes without having to worry about the details. I actually don't oppose this categorically as some do, but I insist on *some* benefit back to the amateur service, such as an interesting new communications system to experiment with and to learn from. Some aren't even willing to go that far. --Phil ___ 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
Re: [amsat-bb] ANS-199 AMSAT News Service Special Bulletin - AMSAT Fox-1C Launch Opportunity Announced
The lack of attitude control forces us to use simple omnidirectional antennas, which in turn keeps us on the crowded and narrow VHF/UHF bands. Worse, there's really no such thing as an omnidirectional antenna so our links are plagued by frequent deep fades of unlimited (or at least unknown) duration. Fading has driven every one of my modulation/coding designs for AMSAT telemetry links -- at the expense of making them much less power-efficient. And power efficient means smaller ground antennas, and that means a cheaper and more accessible ground station for the average ham. And THAT means a much larger potential AMSAT membership. With attitude control, our satellite could use directional antennas on the microwave bands. Directional antennas on higher frequencies mean much better link budgets. Yes, but with who? 95% of everyone in view is more than 45 degrees OUT of the main beam. Directional antennas have zero value on LEO birds that need to serve everyone in view at the same time. And if you only serve those in the main beam, then the duration is under 1 minute. A lack of attitude control also plagues thermal design I think he found the equilibrium temperature of a 1U cubesat to be something like -30 or -40 C! I cannot believe that. The equilibrium of a nominally black (solar panels on all sides) spacecraft is something like about 0 to 30 C (32F to 90F) a very benign operational range. The only time you DO have thermal issues is when you DO have attitude control and have things that are not equally over time seeing the sun and dark sky. PCSAT is now 13 years in orbit and the above range is what it sees. And that range is over a 2 month period. THe orbit-by-orbit temperature changes are less than +/- 10 degrees C. The extremes are due to the seasons of the orbit. When it is seeing eclipses it averages to about 10C and when it is in full sun for weeks at a time, it gets up to 30 C (90F) I do agree that attitude control is nice to have, but my point is that it only makes the thermal problem much worse and that gain is of no value for a LEO where it must see everyone in a footprint at the same time. (Remmebr you cannot have wide beamwidth and gain at the same time). Gain for HEO's of course is another matter! (think AO-10, AO-13 and AO-40) Bob, WB4APR ___ 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
