Linear transponder versus FM transponder for LEO satellites
Hi, The e-mail from I8CVS brings the issue up again. Why not just be happy to get one more transponder for us to use ? If you do not want to use a FM transponder so that be it.
It is interesting to note that there are far more operators on the FM transponder satellites than on the linear satellites in Low Earth Orbit.
Anyway the choice is made by the ones who make and finance the satellites and transponders.
With a height of 500 km FM is probably the way to go. The dopper shift is large. It may be a bad choice for a linear transponder unless you assume that everyone are using full doppler tracking :-)
Sumbandilasat it a very good satellite for operators working portable or mobile. The downlink is strong and it will be better to use it once things settle down. Every time we have a new satellite we have very many wanting to try it out.
I think we should say thank you to our friends in SA for a new one.
73 OZ1MY Ib
I still to this day fail to see how hard it is to twist a VFO knob.
Have we all become soo much appliance operators that we all have forgot to know how to turn a VFO knob to keep someone in tune?
All my early days of Oscar operations we were constantly twisting the large knob. that is what it's for.
wow. un real..
Joe WB9SBD
*The Original Rolling Ball Clock http://www.idle-tyme.com*
OZ1MY wrote:
Hi, The e-mail from I8CVS brings the issue up again. Why not just be happy to get one more transponder for us to use ? If you do not want to use a FM transponder so that be it.
It is interesting to note that there are far more operators on the FM transponder satellites than on the linear satellites in Low Earth Orbit.
Anyway the choice is made by the ones who make and finance the satellites and transponders.
With a height of 500 km FM is probably the way to go. The dopper shift is large. It may be a bad choice for a linear transponder unless you assume that everyone are using full doppler tracking :-)
Sumbandilasat it a very good satellite for operators working portable or mobile. The downlink is strong and it will be better to use it once things settle down. Every time we have a new satellite we have very many wanting to try it out.
I think we should say thank you to our friends in SA for a new one.
73 OZ1MY Ib
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Hi Joe, WB9SBD
The problem here with many new and young satellite operators is like to have many young sparrow that don't know how good is the flavour of wheat
73" de
i8CVS Domenico
----- Original Message ----- From: "Idle-Tyme" nss@mwt.net To: "OZ1MY" oz1my@privat.dk Cc: "AMSAT-BB" amsat-bb@amsat.org Sent: Monday, November 09, 2009 7:17 PM Subject: [amsat-bb] Re: Linear transponder versus FM transponder forLEO satellites
I still to this day fail to see how hard it is to twist a VFO knob.
Have we all become soo much appliance operators that we all have forgot to know how to turn a VFO knob to keep someone in tune?
All my early days of Oscar operations we were constantly twisting the large knob. that is what it's for.
wow. un real..
Joe WB9SBD
*The Original Rolling Ball Clock http://www.idle-tyme.com*
OZ1MY wrote:
Hi, The e-mail from I8CVS brings the issue up again. Why not just be happy to get one more transponder for us to use ? If you do not want to use a FM transponder so that be it.
It is interesting to note that there are far more operators on the FM transponder satellites than on the linear satellites in Low Earth Orbit.
Anyway the choice is made by the ones who make and finance the satellites and transponders.
With a height of 500 km FM is probably the way to go. The dopper shift is large. It may be a bad choice for a linear transponder unless you assume that everyone are using full doppler tracking :-)
Sumbandilasat it a very good satellite for operators working portable or mobile. The downlink is strong and it will be better to use it once things settle down. Every time we have a new satellite we have very many wanting to try it out.
I think we should say thank you to our friends in SA for a new one.
73 OZ1MY Ib
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
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11/09/09 06:11:00
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
i8CVS Domenico wrote... The problem here with many new and young satellite operators is like to have many young sparrow that don't know how good is the flavour of wheat
Joe WB9SBD wrote
I still to this day fail to see how hard it is to twist a VFO knob.
Have we all become soo much appliance operators that we all have forgot to know how to turn a VFO knob to keep someone in tune?
OZ1MY wrote: Why not just be happy to get one more transponder for us to use ? ... It is interesting to note that there are far moreoperators on the FM transponder satellites than on the linear satellites in Low Earth Orbit.
...I think we should say thank you to our friends in SA for a new one.
I find it easy to on side with many of these and similar comments. I don't believe they are mutually exclusive. It is easy to agree to all these. And another BIG THANK YOU from EN19 too!
So rather than waiting for an expensive and probably impossible ride for an AMSAT built satellite LEO or otherwise, FM vs Linear Transponder, perhaps it is time for AMSAT UK, DL, NA et al to be proactive and DONATE a transponder and antennas to the next university CubeSat or Pico sat project. Something such as PE1RAH William Leijenaar's transponder board. A RFP to all those universities now in the planning stages could be sent, an international AMSAT review committee struck to evaluate the merits of those submissions and then finally an annual ( or more often ) donation of the hardware. And to heck with ITAR. If AMSAT NA is hamstrung then I authorize them to take my life membership and transfer the remaining unused portion to AMSAT DL, UK etc.
We buy, they ride and in the spirit of the "Delfi Model" we all win.
And then there is the Genso initiative to assist those universities in near-whole-earth-orbit data acquisition.
Wow.. Why wouldn't they buy into that.
I've stated it here before and I'll repeat it. I don't believe we will ever see another HEO. We amateurs need to connect with, mentor to and volunteer for cube sat and pico sat efforts that are being initiated at the university level. They have the funding, sweat equity and the rides.
And a final reminder, they don't need a ham licence to download telemetry for their science experiments on UHF. They really don't need us. We need them. UHF; we are the secondary user.
Well, actually one more final reminder. We cannot on one hand dumb everything down to an FM HT experience and on the other hand with the AO-40 model do CC-Rider, baud rates in excess of 9K6 etc. There is even a smaller installed base of equipment for those modes than the linear transponder SSB on UHF and VHF. So I don't buy into the argument that FM is the only way to go just because there are more handy talkies than SSB base stations. If that was valid then AO-40 with all it's exotic modes should never have got off the drawing board.
What would y'all do with a dozen FO-29's or VO-52's or a dozen DO-64's with a working voice transponder or even a dozen SO-67's? They are being planned and built right now all around that world in universities and they will be flying with or without us. We can standby and wait. Then complain after they are launched. Or you can check out what your local university is doing right now and get involved. They all need to set up and learn how to run a ground station and that is an expertise you have and they need. You can train them to get their licences so they can do their command and control. There are lots of ways to contribute other than writing a chegue.
We have a political saying up here "If you didn't vote, you have no business complaining about your government". There is an analogy for amateur radio.
Stepping off the soap box...
73, Alan VE4YZ EN19kv AMSAT LM 2352 http://www.wincube.ca
It was mentioned ...
We amateurs need to connect with, mentor to and volunteer for cube sat and pico sat efforts that are being initiated at the university level.
Hmmm, sounds close to what was discussed at the October Board of Director's meeting and early information released on www.amsat.org ... and the ANS news bulletins ... and more details coming via the AMSAT Journal ... plenty already going on the university front!
[From the current amsat web page] Key University Space Projects Under Development
Barry Baines, WD4ASW, AMSAT President reported at the Annual Meeting that the Board of Directors has agreed to participate in two exciting University-based cooperative programs.
* First, AMSAT is having serious discussions with the University of Florida, Gainesville to locate the AMSAT Lab on campus. This will put our lab in a state of the art engineering facility. This is also the home of the UF SwampSat CubeSat development team. * The Board of Directors has agreed to partner with SUNY-Binghamton and the IBM Systems Engineering Integration Center to mentor senior level engineering students for the development of the NextGen CubeSat as their 'capstone' engineering project. Projects at SUNY-Binghamton are planned to initially address the development of deployable solar cells and super capacitor power systems.
[From the AMSAT News Service posted after the BoD meeting and Symposium]
SB SAT @ AMSAT $ANS-291.01 AMSAT Says "We're Going Back to Space"
AMSAT News Service Bulletin 291.01
From AMSAT HQ SILVER SPRING, MD.
October 18, 2009 To All RADIO AMATEURS BID: $ANS-291.01
The Board of Directors has adopted the Engineering Task Force recommendation that low-cost launch options be immediately pursued. The AMSAT engineering team will develop a 1U CubeSat design effective immediately. Tony Monteiro, AA2TX, Vice-President of Engineering said, "We are recommending an approach that gets AMSAT back up in space with new satellites by leveraging the skills and technology we have today."
The new AMSAT CubeSat's initial capability is planned to add to the popular low-earth orbit FM transponder fleet allowing hams to continue to use their existing handheld and portable antenna systems. This also allows an accessible entry path for new satellite operators to get started. The existing FM satellites are starting to show their age.
The flight version of ARISSat-1 has been developed to fit into the CubeSat model. AMSAT's flexible Software Defined Transponder (SDX), simplified IHU, power control subsystem, external interfaces to ex- perimental payloads and cameras will now allow a modular approach to mission design using proven subsystems and components. The ARISSat-1 mission planned in 2010 will be the initial flight test of AMSAT's modular satellite.
Here are some of the highlights ...
+ AMSAT will develop comparable AO-51 level of performance packaged into a 1U CubeSat. This includes a U-V transponder, V telemetry, U command receiver, IHU, power control. This can be done with our modular design.
+ This will be a U/V FM Transponder, not done before in a 1U CubeSat, which can be worked with a HT and a simple antenna. CubeSat power limitations are planned to be addressed through research and devel- opment of deployable solar-cells.
+ AMSAT will make our open-design satellite modules and technology available for other satellite teams to build into their missions.
+ This new approach will provide a reliable radio link for future CubeSats allowing university teams to concentrate on their scientific objectives.
+ The modular nature of the AMSAT CubeSat system will allow add-on missions utilizing several different types of modulation and band- width. These can be pursued with future low-cost CubeSat launch opportunities.
AMSAT President, Barry Baines, WD4ASW Annual Meeting Powerpoint Presentation has been posted at http://www.amsat.org
[ANS thanks the AMSAT Board of Directors for the above information]
/EX
SB SAT @ AMSAT $ANS-291.02 AMSAT, IBM, SUNY-Binghamton Announce NextGen CubeSat Development
AMSAT News Service Bulletin 291.02
From AMSAT HQ SILVER SPRING, MD.
October 18, 2009 To All RADIO AMATEURS BID: $ANS-291.02
AMSAT will work with a university student engineering team to develop the NextGen Cubesat.
NextGen Program Manager, Alex Harvilchuck, N3NP introduced this new program at the AMSAT Symposium. Alex revealed program goals and its initial plans with a paper in the Proceedings and presentations to the AMSAT Board of Directors and to the attendees during Symposium sessions.
NextGen consists of AMSAT volunteer mentors working with IBM Global Services Systems Engineering Division, and SUNY-Binghamton (also called University of Binghamton) senior level engineering students participating in their 'capstone' engineering project.
Alex summarized the NexGen program goals:
+ Intial analysis of ARISSat-1, documenting the systems, and analysis of the lessons learned from ARISSat-1 and other prior spacecraft to create a building block architecture for future satellites.
+ Open, modular, evolutionary, and documented design based on this analysis.
+ Redesigning the ARISSat-1 Power Systems into a next generation power system using supercapacitors instead of batteries and reducing the footprint of some of the boards.
+ Analysis and modification to the structure to incorporate deployable solar panels with a scalable design that will work for 1U, 2U and 3U sizes.
+ Design a Picosat-class bus structure that AMSAT, or any other Univer- sity, can use for 1U, 2U, or 3U CubeSat spacecraft. AMSAT could make the open design available at low-to-no-cost to qualified University groups.
+ An Engineering Model of the NextGen CubeSat spacecraft bus will be on display at the Dayton Hamvention AMSAT Booth for everyone to study.
Alex summarized, "Starting with our initial core team of 34 students, plus advisers, mentors and volunteers at Binghamton University this will be an ongoing effort. It is not a one time event, but the start of a stable, evolutionary design process that will further STEM (Sci- ence, Technology, Engineering & Mathematics) with the Next Generation of engineers and amateur radio operators. We are looking for other individuals and University/School teams to participate in all aspects of the spacecraft design - RF Systems - Guidance, Navigation, Control & Experiment Systems - Power & Structure Systems."
Volunteer mentors are needed! Even if you only have an hour a week, you can mentor a student over the phone or you can peer review a document that the students are working on. If you have more than an hour a week, you can implement a small design change to an existing subsystem; you could respin the board layout to meet a reduced form factor; you could redesign a module to use different technology. Contact Alex via e-mail at amsat@elkmtn.org .
AMSAT's Board of Directors has approved the support of the University of Binghamton NextGen Cubesat Proposal and agreed to provide $1,200.00 in immediate funding to the Binghamton Foundation to support student expenses and initially budgeted $10,000.00 to cover material costs associated with hardware development between September 2009 and May 2010. The Board will review progress at the end of the first semester.
[ANS thanks Alex, N3NP and AMSAT Board of Directors for the above information]
/EX
SB SAT @ AMSAT $ANS-291.03 Discussions Continue For New AMSAT Lab Site
AMSAT News Service Bulletin 291.03
From AMSAT HQ SILVER SPRING, MD.
October 18, 2009 To All RADIO AMATEURS BID: $ANS-291.03
AMSAT President, Barry Baines, WD4ASW discussed an opportunity under serious discussions with the University of Florida, Gainesville to locate AMSAT's satellite laboratory on campus.
Among discussions over the past 12 months, AMSAT has had conversa- tions with several universities concerning a potential relationship. This opportunity arose out of an amateur radio talk given at The Villages ARC by Dave, AA4KN and Drew, KO4MA in April. This lead to contact with UF's Dr. Norman Fitz-Coy. A Memorandum of Understanding has been drafted and is currently under review by legal teams. At this time there is no timeframe for bringing about a formal conclusion as the MOU discussions continue and internal UF approval still needed.
Relocating the AMSAT Lab from the 'Eastern Shore' to 'The Swamp' offers significant potential:
+ Location on a major university campus in a state-of-the-art building
+ Integrated into a facility focused on small satellite development with clean room installation at the host's expense (not AMSAT)
+ Potential for student projects focused on AMSAT needs
+ Broadening of AMSAT's presence in the wider university community
+ Potential research/development opportunities for AMSAT and AMSAT members
+ Establishing a program that offers significant traction for education outreach
[ANS thanks AMSAT President, Barry Baines, WD4ASW for the above information]
/EX
-- 73 de JoAnne K9JKM k9jkm@amsat.org Editor, AMSAT News Service Copy Editor, AMSAT Journal
JoAnne covered a lot of ground. We are also working at having presences at CubeSat and related meetings where many graduate and undergraduate students are present. W5DID's initiative to institute a reduced rate for students in AMSAT membership is a recognition of the need to attract, and keep, new members whose careers will be in space science and technology. Reaching out works both ways. It gets them interested in communications, not just telemetry, and will make it easy to integrate communications packages in research satellites.
We amateurs need to connect with, mentor to and volunteer for cube sat and pico sat efforts that are being initiated at the university level.
Yep, we are doing that.
Alan WA4SCA
OZ1MY wrote:
I think we should say thank you to our friends in SA for a new one.
73 OZ1MY Ib
Well said, Ib!
In the US we have an old saying, "Don't look a gift horse in the mouth". It means do not be critical of others' generosity. It applies here. The Sumbandila team could have just ignored the amateurs and left no room for a secondary payload. As I understand it the repeater makes use of their secondary command and control radio system, which is likely why it is FM based. Frankly I am embarrassed by the complaining and such that has been posted on their blog and here on the -bb by a very few short-sighted amateurs.
There are more university sized satellites being launched every year. Instead of complaining about this or that, how about building some hardware and offering it to these projects. Offer to help them with some problem they have, and perhaps they will help us with our need to get payloads into orbit.
73, Drew KO4MA
In the US we have an old saying, "Don't look a gift horse in the mouth". It means do not be critical of others' generosity. It applies here. The Sumbandila team could have just ignored the amateurs and left no room for a secondary payload. As I understand it the repeater makes use of their secondary command and control radio system, which is likely why it is FM based. Frankly I am embarrassed by the complaining and such that has been posted on their blog and here on the -bb by a very few short-sighted amateurs.
73, Drew KO4MA
I concur it is nice of them to allow the "repeater"...
one can argue over what kind of amateur payload someone puts in "their bird"...and it is pretty pointless since it is their bird for their purposes.
However at the least if it is going to use amateur frequencies, it should in my view have a communication purpose otherwise we are going to see the bands become cheap telemetry bands for payloads which more and more seem to have nothing to do with amateur radio, other then using the frequencies.
anyway the freq sure sounded "wild"
Robert WB5MZO _________________________________________________________________ Hotmail: Trusted email with powerful SPAM protection. http://clk.atdmt.com/GBL/go/177141665/direct/01/
Hello, Ib!
It is interesting to note that there are far more operators on the FM transponder satellites than on the linear satellites in Low Earth Orbit.
Very true. KO4MA spoke to this point at the AMSAT Symposium in Baltimore last month, and I see this anytime I go out to hamfests and struggle to work a couple of stations on nice VO-52 passes. On AO-51 or SO-50 passes, many more than 2 QSOs are made.
I enjoy both the FM and linear satellites, and will continue working both (including AO-7, which I'm now starting to try more often). And, yes, all of this is 100% portable - perfect for road trips, and air travel. :-)
Sumbandilasat it a very good satellite for operators working portable or mobile. The downlink is strong and it will be better to use it once things settle down. Every time we have a new satellite we have very many wanting to try it out.
The SO-67 passes this weekend certainly brought out a large crowd. Everyone trying to make some QSOs to give the new satellite a workout. :-) The downlink is very easy to hear, even if it takes a bit of work to get through the uplink. I am looking forward to more opportunities to work this satellite.
I think we should say thank you to our friends in SA for a new one.
Yes, a big "thank you" to the SA AMSAT crew for the amateur payload, and the South African government and taxpayers for allowing this payload on their satellite.
73!
Patrick WD9EWK/VA7EWK http://www.wd9ewk.net/
participants (9)
-
Alan P. Biddle -
Alan VE4YZ -
Andrew Glasbrenner -
i8cvs -
Idle-Tyme -
JoAnne Maenpaa -
OZ1MY -
Patrick STODDARD (WD9EWK/VA7EWK) -
Rocky Jones