[amsat-bb] Re: SuitSat-II question
Don't get me wrong, the use of the suit is a marketing master-stroke. But am I right that it's basically only there for support (both mechanically and politically)? Yeah, I think it's mostly for media impact. The sight of a lifeless suit floating away from the station is Stanley Kubrick-ish creepy. Rich, N8UX ___ Sent via amsat...@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
[amsat-bb] Re: SuitSat-II question
Greg has picked up on the basic point of the endeavor for AMSAT. We are learning about and developing a modular system that will be adaptable to many projects. This particular project is useful for both ARISS and AMSAT We will have an array of building blocks to configure for missions as they become available, as well as test new technology. Gould - Original Message - From: Greg D. ko6th_g...@hotmail.com To: amsat-bb@amsat.org Sent: Friday, July 03, 2009 10:17 PM Subject: [amsat-bb] SuitSat-II question Hi folks, I just watched the video of Gould Smith talking about SuitSat-II. Nice job. But it left me wondering... With a new battery, solar cells, custom electronics package, switches, and antennas, what is the Suit itself needed for? At least in the original SuitSat, we used the battery pack (I think), and even that's being replaced. Don't get me wrong, the use of the suit is a marketing master-stroke. But am I right that it's basically only there for support (both mechanically and politically)? Greg KO6TH _ Windows Live™ SkyDrive™: Get 25 GB of free online storage. http://windowslive.com/online/skydrive?ocid=TXT_TAGLM_WL_SD_25GB_062009 ___ Sent via amsat...@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...@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
[amsat-bb] More Future Thoughts
It's interesting to watch how the desperation to have assets in high orbit has driven the ideas ever more grandiose here on the old -BB. We've moved from putting a simple transponder (as if there were such a thing) 35,000 miles over our head to landing a repeater a quarter million miles away on the Moon and using robotic rovers to lay directional antennas along the lunar surface... What's next, a Jovian constellation of amateur satellites? This is almost directly the result of having added the government into the fictional scenario. Whenever a new idea starts with, maybe we can get the government to give us a ride... then what follows can be as ostentatious as we like because of the perception that the government can afford to do really BIG things. And we invariably try to justify that they should want to do this because of emergency communication. It would seem to be more constructive to substitute the words big magical genie in your plans everywhere you use the word government or NASA. That way when you write, if we could just get a big magical genie to give us a ride to the Moon... the reality will sink in and it probably won't seem like such a grand idea before it sees the light of day. We need to disabuse ourselves of the ridiculous notion that the government is anxious and willing to stuff our pockets with cash just because when all else fails. Need we be reminded that we're in the midst of the worst global economic recession since the great depression? Tax revenues are low while debt is unbelievably high. Politicians may be stupid but they're going to easily sniff out the nonsense of spending millions of dollars so a few hundred radio hams can enjoy their high-tech hobby. (And who really wants them to do that anyway? What would be your reaction if you read the news tomorrow that the government was going to spend $20 million tax dollars to help promote Frisbee golf, coin collecting, or some other hobby?) When life gives you lemons you make lemonade. We can't get to HEO, so what can we do? I think our best option is to create a lot more interesting things to do at LEO since we know we can get there; but let's make sure we aren't leaving a stone un-turned. What about other orbits that may not be as desirable as HEO but that offer better coverage than low-earth? I recall reading something from G0RMF about adapting a CubeSat to include some sort of a propulsion system to get to a mid-Earth orbit: http://g0mrf.com/MEOSAT.htm I have no idea if this is viable, but it seems to me that if we want to place assets higher than LEO these are the kinds of ideas we should be kicking around on the BB and perhaps leave the moon base installation ideas for AMSAT members in 2050 to figure out how to make work and to fund. -- 73 de Jeff, KE9V AMSAT-NA AMSAT-DL ___ Sent via amsat...@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
[amsat-bb] Antenna Question
Happy Independence Day. Does anyone recognize the following antennas? I purchased them years ago and they were part of a system I never installed. Over the years, one of the elements has been damaged and, even though I can fix it myself, I'd like to know who made these. Doggonit, I cannot upload to my webpage (something else yet to figure out). Suffice it to say, my description may not do the antennas justice. There are two of them, a 2m and 70cm made out of sched 40 PVC. They appear to be a turnstile type antenna with two aluminum elements at the top and two at the bottom 90° out of phase from each other (top and bottom). In other words, if looking at a compass, the top two elements would be at N and S, the bottom two at E and W. This is the same on both antennas as they are a matching set. These antennas were in an old QST, but I have since gotten rid of all those magazines and cannot find the article online. Any ideas or suggestions? Tnx, Joel, W4JBB ___ Sent via amsat...@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
[amsat-bb] Re: The Moon is our Future / antennas
Hello David, Principally, the same as the Fyllingsdales BMEWS steerable phased array, yes ??. We have some info on it on OBSERVATIONS. http://www.observations.biz) 73 John. la2...@amsat.org . From: g0...@aol.com Date: Fri, 3 Jul 2009 19:21:08 -0400 To: kd6...@comcast.net; amsat-bb@amsat.org Subject: [amsat-bb] The Moon is our Future / antennas In a message dated 03/07/2009 20:46:44 GMT Standard Time, kd6...@comcast.net writes: Building a prototype that works on Earth for project like this is only a few percent of the effort required. Treating it as a radio club project won't be effective as people need to sign up for a 5-year project. Hi all. John is absolutely right in saying the complexity cannot be easily compared to a terrestrial radio project. One other thing that stands an almost zero chance of succeeding is a dish antenna that needs to point towards the earth. If NASA and the ISS have trouble with moving parts on the solar array you can imagine how much more difficult it would be on the moon. However, how about this. The problem with the higher bands is power generation / path loss / antenna gain. Any higher band like 1.2, 2.4 or 5.8G would need a high gain antenna to offset the increased path loss. But, instead of a conventional steerable dishwith its unreliable moving joints...How about an electrically steerable array of patches / dipoles / or any other type of antenna element. But how to 'point' it? Well. actually I think Tom Clark provided the answer for that with his proposal of a few years ago. The principle is this: If you have 2 arrays. One say on 5.6G uplink and one on 5.8G downlink, then the receiving array can electrically look in different directions for a signal from the Earth. Once the receiver has identified a signal and optimised the RX Antenna, the information on the direction of the Earth i.e. the direction of the strongest incoming signal can be used to configure the transmit array which will then beam a signal back to earth with high ERP. Directional, high gain, and no moving parts. Thanks David G0MRF ___ Sent via amsat...@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 _ Drag n’ drop—Get easy photo sharing with Windows Live™ Photos. http://www.microsoft.com/windows/windowslive/products/photos.aspx ___ Sent via amsat...@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
[amsat-bb] Re: Antenna Question
Sounds like the QHTennas, made by N4QH. Reviewed in QST in 2005, then he stopped producing them just a few months later. Near as I could figure out, they are a conventional turnstile design, but with the 2 dipoles separated by the length of the phasing line, and no reflector. George, KA3HSW - Original Message - From: Joel Black jbbl...@charter.net To: amsat-bb@amsat.org Sent: Saturday, July 04, 2009 9:50 AM Subject: [amsat-bb] Antenna Question Happy Independence Day. Does anyone recognize the following antennas? I purchased them years ago and they were part of a system I never installed. Over the years, one of the elements has been damaged and, even though I can fix it myself, I'd like to know who made these. Doggonit, I cannot upload to my webpage (something else yet to figure out). Suffice it to say, my description may not do the antennas justice. There are two of them, a 2m and 70cm made out of sched 40 PVC. They appear to be a turnstile type antenna with two aluminum elements at the top and two at the bottom 90° out of phase from each other (top and bottom). In other words, if looking at a compass, the top two elements would be at N and S, the bottom two at E and W. This is the same on both antennas as they are a matching set. These antennas were in an old QST, but I have since gotten rid of all those magazines and cannot find the article online. Any ideas or suggestions? Tnx, Joel, W4JBB ___ Sent via amsat...@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
[amsat-bb] Re: AMSAT Forum videos from Dayton Hamvention
Hi Steve! Videos of the six presentations at the AMSAT Forum at the 2009 Dayton Hamvention are now on the AMSAT website. Click on this link http://www.amsat.org/amsat-new/information/videoNews.php or go to the AMSAT website and click on AMSAT Video News about halfway down the page in the left column. Thanks for your work with the camcorder at Dayton! During the AMSAT Forum, I had asked if videos would be made available in some form - and it's nice that they have. I will look at them when I return home tomorrow, and have access to broadband. A question... regarding Richard Garriott, you uploaded one video of Richard speaking during the AMSAT Forum at the HamVention: 1. Richard Garriott's forum talk (mislabeled on the web site as the Banquet presentation, actual length about 15 minutes) on his visit to the ISS. Is there any chance of posting Richard's talk at the AMSAT/TAPR Banquet the night before the AMSAT Forum? I thought I saw you with the camcorder there as well. That talk was longer, and would be a great addition to what Richard said at the Forum. 73! Patrick WD9EWK/VA7EWK http://www.wd9ewk.net/ ___ Sent via amsat...@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
[amsat-bb] Re: AMSAT Forum videos from Dayton Hamvention
Yes indeed. Richard's presentation at the AMSAT forum was a much shorter version of the one he gave at the Banquet the night before and it would be great to have that in the archives. 73 -- David KG4ZLB www.kg4zlb.com Patrick STODDARD (WD9EWK/VA7EWK) wrote: Hi Steve! Thanks for your work with the camcorder at Dayton! During the AMSAT Forum, I had asked if videos would be made available in some form - and it's nice that they have. I will look at them when I return home tomorrow, and have access to broadband. A question... regarding Richard Garriott, you uploaded one video of Richard speaking during the AMSAT Forum at the HamVention: Is there any chance of posting Richard's talk at the AMSAT/TAPR Banquet the night before the AMSAT Forum? I thought I saw you with the camcorder there as well. That talk was longer, and would be a great addition to what Richard said at the Forum. 73! Patrick WD9EWK/VA7EWK http://www.wd9ewk.net/ ___ Sent via amsat...@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 -- David KG4ZLB www.kg4zlb.com ___ Sent via amsat...@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
[amsat-bb] Re: Antenna Question
Oh My! Somebody else has my warped sence of humor:-) Just ask my granddaughter. I goof with her all the time with stuff like this. Like when she asks to get on the computer and I tell her she will break it if she does:-) RoD KD0XX --- On Sat, 7/4/09, David - KG4ZLB kg4...@googlemail.com wrote: From: David - KG4ZLB kg4...@googlemail.com Subject: [amsat-bb] Re: Antenna Question To: amsat-bb@amsat.org Date: Saturday, July 4, 2009, 11:28 AM How can you upload a web page if you have your dog on it ? Move the dog first then try! ;-) Happy 4th all! 73 -- David KG4ZLB www.kg4zlb.com Joel Black wrote: Happy Independence Day. Doggonit, I cannot upload to my webpage (something else yet to figure out). ___ Sent via amsat...@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...@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
[amsat-bb] Re: Antenna Question
The product review is in the August 2004 QST. If you have access to the reviews page you can find it under the Q listings by manufacturer. Jim KQ6EA --- On Sat, 7/4/09, George Henry ka3...@att.net wrote: From: George Henry ka3...@att.net Subject: [amsat-bb] Re: Antenna Question To: amsat bb amsat-bb@amsat.org Date: Saturday, July 4, 2009, 8:51 AM Sounds like the QHTennas, made by N4QH. Reviewed in QST in 2005, then he stopped producing them just a few months later. Near as I could figure out, they are a conventional turnstile design, but with the 2 dipoles separated by the length of the phasing line, and no reflector. George, KA3HSW - Original Message - From: Joel Black jbbl...@charter.net To: amsat-bb@amsat.org Sent: Saturday, July 04, 2009 9:50 AM Subject: [amsat-bb] Antenna Question Happy Independence Day. Does anyone recognize the following antennas? I purchased them years ago and they were part of a system I never installed. Over the years, one of the elements has been damaged and, even though I can fix it myself, I'd like to know who made these. Doggonit, I cannot upload to my webpage (something else yet to figure out). Suffice it to say, my description may not do the antennas justice. There are two of them, a 2m and 70cm made out of sched 40 PVC. They appear to be a turnstile type antenna with two aluminum elements at the top and two at the bottom 90° out of phase from each other (top and bottom). In other words, if looking at a compass, the top two elements would be at N and S, the bottom two at E and W. This is the same on both antennas as they are a matching set. These antennas were in an old QST, but I have since gotten rid of all those magazines and cannot find the article online. Any ideas or suggestions? Tnx, Joel, W4JBB ___ Sent via amsat...@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...@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
[amsat-bb] Re: The Moon is our Future / antennas
- Original Message - From: g0...@aol.com To: kd6...@comcast.net; amsat-bb@amsat.org Sent: Saturday, July 04, 2009 1:21 AM Subject: [amsat-bb] The Moon is our Future / antennas In a message dated 03/07/2009 20:46:44 GMT Standard Time, kd6...@comcast.net writes: Building a prototype that works on Earth for project like this is only a few percent of the effort required. Treating it as a radio club project won't be effective as people need to sign up for a 5-year project. Hi all. John is absolutely right in saying the complexity cannot be easily compared to a terrestrial radio project. One other thing that stands an almost zero chance of succeeding is a dish antenna that needs to point towards the earth. If NASA and the ISS have trouble with moving parts on the solar array you can imagine how much more difficult it would be on the moon. However, how about this. The problem with the higher bands is power generation / path loss / antenna gain. Any higher band like 1.2, 2.4 or 5.8G would need a high gain antenna to offset the increased path loss. But, instead of a conventional steerable dishwith its unreliable moving joints...How about an electrically steerable array of patches / dipoles / or any other type of antenna element. But how to 'point' it? Well. actually I think Tom Clark provided the answer for that with his proposal of a few years ago. The principle is this: If you have 2 arrays. One say on 5.6G uplink and one on 5.8G downlink, then the receiving array can electrically look in different directions for a signal from the Earth. Once the receiver has identified a signal and optimised the RX Antenna, the information on the direction of the Earth i.e. the direction of the strongest incoming signal can be used to configure the transmit array which will then beam a signal back to earth with high ERP. Directional, high gain, and no moving parts. Thanks David G0MRF Hi David, G0MRF The following article from G3RUH is a good additional answere to your message. http://www.amsat.org/amsat/articles/g3ruh/110.html I have extracted from it the most important following part: 73 de i8CVS Domenico Extracted from G3RUH article THE EARTH MOVES Moon Downlink The maximum total excursion of 9.5° is the same as the beamwidth of a 5 wavelength diameter dish antenna. This has a gain of some 20 dbi, and represents an upper limit for an unsteered Moon-based antenna. However the higher the frequency used, the smaller mechanically is the antenna, which makes 2.4 or 5.6 GHz a good choice. Five wavelengths is 60 cm and 26 cm diameter respectively; quite small. For a given TX e.i.r.p., signal strength received at Earth depends only on the mechanical size of the RX antenna; frequency is irrelevant [1]. Noise level however is not, and S-band (2.4 GHz) is a sensible downlink choice because very low noise performance is robustly obtainable off the shelf. An example, 1 watt transmitted from a 20 dbi gain dish on the Moon, received on a 1.2m dish at Earth with a system noise temperature of 100K results in a signal to noise ratio in 2.4 kHz bandwidth of 10.5 db. (Note that frequency matters not). This would support one rather noisy SSB voice signal. Alternatively it would carry an error-free 2400 bps binary PSK data transmission without coding, 9600 bps with modest coding [2]. ___ Sent via amsat...@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
[amsat-bb] The Moon is not our future
Thanks to all contributors for an enjoyable thread, with some very interesting ideas, however, there is a fundamental obstacle to transponders on the Moon. The science packages used and left on the Moon by the Apollo astonauts had radioactive heat sources which prevented the electronics from being destroyed by the extreem cold of the lunar night. I don't believe there is any likelyhood that we can fly a radioactive source on an amateur radio payload. 73 John G7HIA ___ Sent via amsat...@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
[amsat-bb] Re: Antenna Question
Yeah, I found the review on the ARRL web site by searching for QHTenna. Looking at the pictures, it appears that the dipoles are separated by about 1/4 wave in free space, which is physically longer than a 1/4 wave phasing line would be. And I'd think that the phasing line would have to be 1/2 wavelength, after introducing a 1/4 wave offset between the dipoles, correct? In answer to Joel's original question, there is a link at www.qhtenna.com for questions or support for owners of existing QHTennas. They should be pretty easy to duplicate, at any rate. George, KA3HSW - Original Message - From: Jim Jerzycke kq...@pacbell.net To: amsat bb amsat-bb@amsat.org; George Henry ka3...@att.net Sent: Saturday, July 04, 2009 1:54 PM Subject: Re: [amsat-bb] Re: Antenna Question The product review is in the August 2004 QST. If you have access to the reviews page you can find it under the Q listings by manufacturer. Jim KQ6EA --- On Sat, 7/4/09, George Henry ka3...@att.net wrote: From: George Henry ka3...@att.net Subject: [amsat-bb] Re: Antenna Question To: amsat bb amsat-bb@amsat.org Date: Saturday, July 4, 2009, 8:51 AM Sounds like the QHTennas, made by N4QH. Reviewed in QST in 2005, then he stopped producing them just a few months later. Near as I could figure out, they are a conventional turnstile design, but with the 2 dipoles separated by the length of the phasing line, and no reflector. George, KA3HSW ___ Sent via amsat...@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
[amsat-bb] Re: Antenna Question
I would suggest that you don't need a phasing line if the dipoles are spaces a quarter wave and that both are fed by equal length cables. George Henry wrote: Looking at the pictures, it appears that the dipoles are separated by about 1/4 wave in free space, which is physically longer than a 1/4 wave phasing line would be. And I'd think that the phasing line would have to be 1/2 wavelength, after introducing a 1/4 wave offset between the dipoles, correct? ___ Sent via amsat...@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
[amsat-bb] Re: More Future Thoughts
At 11:13 PM 7/4/2009, Jeff Davis wrote: What about other orbits that may not be as desirable as HEO but that offer better coverage than low-earth? I recall reading something from G0RMF about adapting a CubeSat to include some sort of a propulsion system to get to a mid-Earth orbit: This idea does have merit. As you've implied, we'd probably never get a ride directly to such an orbit, so some means of (relatively) foolproof and (relatively) inexpensive means of propulsion would need to be utilised. Someone would also need to do the delta-V calculations, to see what sort of orbit would be feasible for such a small satellite to achieve. There's also the possible issue of the satellite spending most of its life in the Van Allen belts, unless we can get the altitude just right. 73 de VK3JED / VK3IRL http://vkradio.com ___ Sent via amsat...@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
[amsat-bb] Re: Antenna Question
That's them. Thanks, George and, David, I got the dog off the webpage. ;) Tnx, Joel, W4JBB George Henry wrote: Sounds like the QHTennas, made by N4QH. Reviewed in QST in 2005, then he stopped producing them just a few months later. Near as I could figure out, they are a conventional turnstile design, but with the 2 dipoles separated by the length of the phasing line, and no reflector. George, KA3HSW - Original Message - From: Joel Black jbbl...@charter.net To: amsat-bb@amsat.org Sent: Saturday, July 04, 2009 9:50 AM Subject: [amsat-bb] Antenna Question Happy Independence Day. Does anyone recognize the following antennas? I purchased them years ago and they were part of a system I never installed. Over the years, one of the elements has been damaged and, even though I can fix it myself, I'd like to know who made these. Doggonit, I cannot upload to my webpage (something else yet to figure out). Suffice it to say, my description may not do the antennas justice. There are two of them, a 2m and 70cm made out of sched 40 PVC. They appear to be a turnstile type antenna with two aluminum elements at the top and two at the bottom 90° out of phase from each other (top and bottom). In other words, if looking at a compass, the top two elements would be at N and S, the bottom two at E and W. This is the same on both antennas as they are a matching set. These antennas were in an old QST, but I have since gotten rid of all those magazines and cannot find the article online. Any ideas or suggestions? Tnx, Joel, W4JBB ___ Sent via amsat...@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...@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
[amsat-bb] Re: More Future Thoughts
At 02:52 AM 7/5/2009, you wrote: AMSAT as a whole (I mean the membership) needs a new challenge and dream that will bring out the very best in it to build what ever comes up. The Moon could be that new challenge as we have NEVER designed anything that would actually LAND and operate in that hostile environment. Is it viable, who knows! We can only ask ourselves that question and then step up to the challenge. Well, the challenge as I see it is not so much in the RF side of things, but being to take advantage of the available (relatively affordable) launch opportunities available (i.e. LEO), then coming up with a way to being able to move the bird into an orbit more suitable. Yes, propulsion hasn't been AMSAT's strong point, but for most of the last 20 years, I only recall LEOs being put up (AO-40 being the only exception I can recall in that timeframe). So the challenge is to find a means of propulsion that is relatively safe, inexpensive and lightweight, but can move a satellite into a significantly higher orbit (e.g. MEO). I'd imagine that such a form of propulsion is probably only found in science fiction, but how close can one get in the real world? Are there any universities working on cheaper ways to move satellites around, once launched, that need a suitable test mass (that happens to have a transponder or two on board)? 73 de VK3JED / VK3IRL http://vkradio.com ___ Sent via amsat...@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
[amsat-bb] Re: controller and Rotator help
Since no one has replied thought I might give it another try, while perhaps not many are familiar with MacDoppler software, I hope some would be with the hardware and wouldn't mind offering some help? thanks happy 4th On Jul 3, 2009, at 4:47 PM, myles landstein wrote: Hoping to get some real world advice from those that are using MacDoppler and a compatible Rotor /Controller set up as this will be my first time getting a rotator and controller. I wanted to solicit some advice on two fronts, the rotor controller basically for ease of use with MacDoppler and rotor reliability. My first thoughts were towards a Yaesu 5500 and maybe the PrimeTec controller or maybe the LVB tracker as it's less costly. I read a few reviews but not much was out there in general but especially on the PrimeTec... Anyone using the PrimeTec? What are you using as a controller? would appreciate any comparisons pro's cons tips tricks you might have My biggest concern really is the Rotator. I am in a situation such that after installation, getting back to the roof for repairs would be rather difficult. So i am trying to identify the 'best' small/moderate sized rotator (az/el) as possible /practical. Will be turning a small M2 2m and 440 circular pol beam Not really sure how reliable the 5500 is for long term use. so if there was a 'better' more reliable and or longer lasting rotor out there i'd strongly consider it The only thing I thought of as a alternative was the AlphaSpid but comparing reviews I seem to come out about the same between it and the 5500 -hoping some real world responses might help me break the 'tie' Since this is all new stuff and I am not finding the usual quality 'google' results /reviews (PrimeTec) I would greatly appreciate any help or experience /advice on this from someone that went down this road already and willing to share some first hand info on what they use. thanks very much grateful for any advice. Going to Dayton '10 It will get better with more support! Myles D Landstein N2EHG myles.landst...@gmail.com Myles Landstein myles.landst...@gmail.com please note my new email address dti will soon be eliminated , gmail is my new home update your dir ___ Sent via amsat...@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
[amsat-bb] Re: controller and Rotator help
Myles, My antennas/rotor are disassembled right now, as we are trying to sell the house. When it was all together, I used an older version of MacDoppler Pro, a Mac G4 tower with a serial card, and an Endeavour Auto Tracker ( http://endeavour-usa.com/ autotracker.htm ) driving a Yaesu 5400 rotor. The system worked FB. Had I to do it over, I might not choose the Endeavour interface unit. It requires a serial port on the Mac, and I'm not sure if a serial-to USB converter would work right with it (an Imac, for instance, has no provision for a serial card). MacDoppler is an excellent program with great support. The 5400 was purchased used and has been up on my roof for a number of years with no problems. A friend of mine (who may not subscribe to this list) is using a Mac, MacDoppler and a Yaesu 5400. I will email him and see what he is using for an interface unit (I think his Mac is USB-only), and let you know. Bill Howell N5AB On Jul 4, 2009, at 8:12 PM, myles landstein wrote: Since no one has replied thought I might give it another try, while perhaps not many are familiar with MacDoppler software, I hope some would be with the hardware and wouldn't mind offering some help? thanks happy 4th On Jul 3, 2009, at 4:47 PM, myles landstein wrote: Hoping to get some real world advice from those that are using MacDoppler and a compatible Rotor /Controller set up as this will be my first time getting a rotator and controller. I wanted to solicit some advice on two fronts, the rotor controller basically for ease of use with MacDoppler and rotor reliability. My first thoughts were towards a Yaesu 5500 and maybe the PrimeTec controller or maybe the LVB tracker as it's less costly. I read a few reviews but not much was out there in general but especially on the PrimeTec... Anyone using the PrimeTec? What are you using as a controller? would appreciate any comparisons pro's cons tips tricks you might have My biggest concern really is the Rotator. I am in a situation such that after installation, getting back to the roof for repairs would be rather difficult. So i am trying to identify the 'best' small/moderate sized rotator (az/el) as possible /practical. Will be turning a small M2 2m and 440 circular pol beam Not really sure how reliable the 5500 is for long term use. so if there was a 'better' more reliable and or longer lasting rotor out there i'd strongly consider it The only thing I thought of as a alternative was the AlphaSpid but comparing reviews I seem to come out about the same between it and the 5500 -hoping some real world responses might help me break the 'tie' Since this is all new stuff and I am not finding the usual quality 'google' results /reviews (PrimeTec) I would greatly appreciate any help or experience /advice on this from someone that went down this road already and willing to share some first hand info on what they use. thanks very much grateful for any advice. Going to Dayton '10 It will get better with more support! Myles D Landstein N2EHG myles.landst...@gmail.com Myles Landstein myles.landst...@gmail.com please note my new email address dti will soon be eliminated , gmail is my new home update your dir ___ Sent via amsat...@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...@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
[amsat-bb] Future satellites
An interesting question for the short term is what can we do with 1 watt of RF from a LEO satellite. RS-10 and RS-12 were interesting as they required only omnidirectional antennas but they had a lot of power available as they were attached to much larger satellites. AO-16 was a small satellite but was capable of only 1200 bps data using uncoded BPSK and simple vertical antennas. Given the type of hardware developed for Suitsat-2, we should be able to do a lot more. Using modern error-correcting codes 4800 bps is possible using omnidirectional antenas and with modern codecs that can carry 4 voice channels or 3 voice channels plus 40 PSK31-like channels. With 10 dBi of gain at the ground station the data rate and number of voice channels could be quadrupled. The downlink could also be split between 2 voice channels for use with omnidirectional antennas and 8 voice channels for high-gain antennas. 73, John KD6OZH I have extracted from it the most important following part: 73 de i8CVS Domenico Extracted from G3RUH article THE EARTH MOVES An example, 1 watt transmitted from a 20 dbi gain dish on the Moon, received on a 1.2m dish at Earth with a system noise temperature of 100K results in a signal to noise ratio in 2.4 kHz bandwidth of 10.5 db. (Note that frequency matters not). This would support one rather noisy SSB voice signal. Alternatively it would carry an error-free 2400 bps binary PSK data transmission without coding, 9600 bps with modest coding [2]. ___ Sent via amsat...@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
