September 2006 - Eagle (INACTIVE)

Proposed Eagle Antenna Arrays
by Louis McFadin 01 Oct '06

01 Oct '06

Here is a proposal for arranging the Eagle antennas that Stan Wood and I worked out today. By moving the 2M dipoles to the corners we have sufficient room for full sized elements over the ground plane. The 2M antennas should get about 8dB. Three L band patches in cavities should give us greater than 12 dB gain. By putting the S1,S2 and C band patches in hex shaped cups we maximize the available space. The cup arrays can be NC machined out of a solid blank and therefore attain precise control of the spacing. It may also serve as heat a radiating device. Each patch will be circular polarized and fed with a single feed from it's matching amplifier. The 70 CM Circular polarized patch should have around 6 dB gain. We will look at getting more gain on 70 cm. Seven S1 patches will be mounted on top the 70CM patch. They should get about 15dB gain. Tom's S2 interferometric patches are included. Omni antennas similar to that used on P3D will be required on the opposite side of the spacecraft. There should also be room for the Sun Sensors on both sides of the spacecraft. Lou McFadin W5DID w5did(a)mac.com

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Presidents club reception - San Francisco
by R.Haighton 27 Sep '06

27 Sep '06

Hi All, As members of the Board of Directors and members of the Eagle group, You are invited to the "Presidents Club" reception on Friday Evening October 6th 7.00 pm. The object of this reception is to allow the major financial Supporters of AMSAT , our Prominent designers and Builders, and the Board of directors to meet, exchange views, and Gain enlightenment on the various aspects of our organization. I look forward to seeing you there. 73 Robin Haighton VE3FRH

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Eagle 2007 budget input
by Jim Sanford 26 Sep '06

26 Sep '06

All: Attached is my input for the 2007 budget. It is based on a few inputs, some carried over items from 2006 that we didn't (but need to) do, and my best guess on a couple of things. 73, Jim wb4gcs(a)amsat.org

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Antenna Plans
by Dick Jansson-rr 26 Sep '06

26 Sep '06

It is well that the antenna plans are starting to congeal. I do have some comments upon the diagram that John presented, herewith attached. 1) There is an option, whether employed or not, that the U band could be the stacked CP patch design previously shown, with the L band array mounted thereon, also as previously shown. 2) The U band antenna currently shown in John's design could use a modification of the dipole design used for all of the AMSAT-DL P3 satellites. We call that "design adaptation" (not stealing!). 3) The V band antennas are of a great concern as shown in John's design. The P3D V antennas were more than 880mm end-to-end span, and a nominal 144mm spaced off of the spaceframe. Three of these on top of the Eagle seems to me to be of a gargantuan, unwieldy concept. These antennas would greatly impact the spacecraft envelop as mounting in a launcher. John has talked of a bent-end antenna design, is that really practical from an RF sense? I am wondering if some form of dual-feed full-wave V band loop might not serve better in this application. Stan Wood had shown such a full-wave loop design for the Small Eagle that was only about 50mm high. Properly designed, it would not necessarily have to be 144mm high, so I am led to believe. Can some astute antenna designer look at this for us? I feel that we need to look at the options. Dick Jansson --------------------------- <mailto:rjansson@cfl.rr.com> rjansson(a)cfl.rr.com ---------------------------

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Another New Rocket Fails
by Tom Clark, K3IO 26 Sep '06

26 Sep '06

>From the "It Really Is Rocket Science" department -- this one from New Mexico -- see http://news.bbc.co.uk/2/hi/science/nature/5377958.stm

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Eagle power requirements
by Louis McFadin 25 Sep '06

25 Sep '06

Jim, Do we have any idea how much power Eagle will require in the two different modes 1 In sunlight and 2 during eclipse? Should we design for the 10 hour orbit that Ken used for his studies? In that orbit the worst case eclipse is about two hours and most of the time it is far less. I know we have asked that question before. Maybe it's time to get serious about establishing a power budget. The answers to these questions will drive much of the design of the spacecraft. Lou

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Where we're heading for bands and services
by Jim Sanford 25 Sep '06

25 Sep '06

Team: The Eagle Chief Technology Officer (W2GPS), the AMSAT VP Engineering (N4HY) and I met (electronically) to discuss the Eagle payload complement. We have decided the following should be our recommendation to the board of directors of AMSAT for their ratification. This is what will be presented to the BoD: 1. Services to be provided, as defined at the San Diego meeting et seq: Class 0 is linear transponder users Class 1 is SMS text message service users Class 2 is weak signal voice grade digital channel Class 3 is strong signal, large antenna, higher bandwidth signal (think compressed full motion video) 2. Primary class 0 payload: U/V with a design goal that it be usable over 75% of the orbit. 3. Primary class 1 payload: U/V for the reasons discussed at San Diego. 3. Primary Class 2 and 3 ACP payload: S2/C usable over 75% of the orbit. This coverage to be accomplished by using electronically de-spun phased arrays on S2 and C. At San Diego, we discussed S2 vs. S1. S2 was technically superior, but other issues caused us to shy away from it. Upon reflection, the leadership has decided to proceed down the technically superior path, S2 uplink. 4. Secondary Class 0 payload: L/S1 -if and when the power budget and antenna pointing (fixed, nadir-pointing array) can support. We recognize that it may not be usable in many areas due to elevated noise floor resulting from 802.xx devices, as discussed in San Diego and documented in measurements and analysis. NO PERFORMANCE LEVEL IS TO BE PROMISED. 5. Secondary ACP Class 2 uplink: A separate L receiver feeding same DSP and C-band downlink when fixed nadir-pointing antenna array supports. This second receiver will share the L-band LNA and antenna with the L/S1 Class 0 payload. The greater level of service for S2 users should encourage people who can to use S2 rather than L. NO PERFORMANCE LEVEL IS TO BE PROMISED. 6. Use of all secondary payloads will be subject to acceptable costs in power, heat, and/or mass, as assessed by analysis or testing. They are to be turned off if regulatory constraints are imposed post launch. They will not be flown at all if shown to be not feasible through analysis or testing. This is what I will present to the board at Symposium for their concurrence. Please contain this discussion within the Eagle team until the Board makes a decision. I request your comments within the next 48 hours so that I can finish the budget tonight and begin crafting my presentation to the board and my follow-on presentation at Symposium. We need to bring this to closure so that we can present decisions at Symposium, and move out smartly from there. Thanks. Very 73, Jim wb4gcs(a)amsat.org <mailto:wb4gcs@amsat.org> UNQUOTE

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New Modus Vivendi for Eagle/Engineering and my analysis of our needs
by Robert McGwier 25 Sep '06

25 Sep '06

We have what I consider to be a firm decision on how to proceed. I am proud of where we are a year into my tenure. The details clearly need to be fleshed out but we have a way forward that I suspect technical people and user people can rally behind since it involves compromise and calculation. Rick Hambly has provided some necessary leadership here and I choose to get behind it to implement it. It is not everyone's ideal choice but it is a choice I can support. For your information, we need desperately to get our act together on several different fronts and these are organizational in nature. I need to modify my role significantly now. I believe Jim will be much more comfortable now that we have a reasonably clear direction. He has fixed my greatest concern in that he has demonstrated usable internet connectivity that he can check wherever he is doing his normal daily living which requires travel. I believed he was completely ineffective when he could not communicate in a timely fashion. I saw emails get answered that were clearly "four generations" old in a thread and it aggravated me a lot. That has been completely fixed in my opinion recently. It is clear that with team member scattered over the world and the continent, effective telecommunications are absolutely required to effectively manage this project. I did not view this as fixed until two weeks ago. I now view it as fixed. Since I am a known commodity to many of you, many of you come to me with things that should go directly to Jim. This undermines Jim in his attempt to manage the project. In addition, dealing with you individually actively hinders me doing exactly those things I need to do on an organizational level and slows some technical work that I personally responsible for. Jim and I have repeatedly run into things we thought the other was doing. Jim has fixed his telecom problems and I am now a reflector. Jim works for me since Eagle is engineering but this is going to be an organizational lead where I do composite budgets and make facilities available from the organization but I am not going to do daily management. Direct stuff to Jim. Let me give three examples of those things I am going to be concentrating on in the next 30 days. 1) IHU-3 code since P3E needs a control mechanism to integrate. 2) Finishing a top level mechanical analysis, laying out design principles in spreadsheet form so we can place equipment inside our chosen model, and put the attitude control system in. I will be concentrating on helping the sensor team (welcome back Alan) get the big picture right. 3) SDR things that I am uniquely qualified to do, inextricably committed to doing, or am required to help with in a "hands on" way. It is clear that we have won the battle to get the kinds of transponders we need to make this a new and different spacecraft. It will be technically challenging and that will be the fun part! I am no longer needed to lead the transponder team is my read and it needs someone who can dedicate themselves to that aspect of this. The team I have helped to assemble has an amazing collection of talent in it. Managed correctly, this team simply cannot fail. I need someone to step up and take over the transponder management and Jim should now take charge of finding that person. I do not wish to do more than advise Jim on his selection when he has some choices. For Jim to succeed in implementing these transponders, he needs to find someone he can work with so I bow out of the selection except to give solicited advise. Jim and I discussed this and I agree with his assessment that the team is better off being lead elsewhere. It would be my suggestion to Jim that the person he picks understands that this is really two teams being forced into the same "bucket": linear and ACP and they must be welded into an RF team. I think we are close to announcing a construction, integration, testing facility. We will know in 30-45 days. I need to budget time for doing the planning on taking care of organizational business in the area of getting this lab going and getting our engineering house in order totally, not just for Eagle. This is exciting since I think we can set up a long term facility that is closer to the corporate offices, and can help our organization's educational status, and more. This is going to require a serious effort to complete by the end of the year. I believe this is the best use of my time for AMSAT in general and Eagle in particular outside of those specific technical tasks I have undertaken. HPSDR and GnuRadio are, in my opinion, the most important technical projects outside of AMSAT for OUR future. They will have a large impact on amateur radio in general, and AMSAT in particular. We have engineering management things to get right with our sister organization TAPR. This will heat up in the next few months. After I get the top level mechanical analysis work done with Bob Davis and Dick Jansson, I need to pass off that hat to someone who can live with it day to day. Should we actually make the organizational move on a laboratory that I think we are about to make, I will give my recommendation to Jim but I will need to back out of making this selection and limit my role to computation. The recommendation will be obvious if this falls into place. As V.P. Engineering I will insist on being on all peer review committees and exactly how that will function will be worked out with Jim. Any further advice to the teams will be directed to individuals but will ALL contain CC to Jim. As an organizational matter, we need Jim to succeed and he needs to take the lead. He will have my support (and my friendly cattle prod) to do exactly that. Bob N4HY -- AMSAT VP Engineering. Member: ARRL, AMSAT-DL, TAPR, Packrats, NJQRP/AMQRP, QRP ARCI, QCWA, FRC. ARRL SDR Wrk Grp Chairman "You see, wire telegraph is a kind of a very, very long cat. You pull his tail in New York and his head is meowing in Los Angeles. Do you understand this? And radio operates exactly the same way: you send signals here, they receive them there. The only difference is that there is no cat." - Einstein

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IF switching
by Howard Long 24 Sep '06

24 Sep '06

Folks, I believe that I read somewhere recently (although I can't seem to find it now) that the concept of an IF switching matrix has been discounted. I don't know what the reason for this was, however on the basis that it seems clear that no-one is sure what bands may or may not be useable or available over the next few years, is it worth re-addressing this for feasibility? Howard

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Conference Papers
by Robert McGwier 23 Sep '06

23 Sep '06

If you have an outstanding paper, they must be in by tomorrow evening and the earlier the better. Jean and Emily need to go to print on Monday. Bob -- AMSAT VP Engineering. Member: ARRL, AMSAT-DL, TAPR, Packrats, NJQRP/AMQRP, QRP ARCI, QCWA, FRC. ARRL SDR Wrk Grp Chairman "You see, wire telegraph is a kind of a very, very long cat. You pull his tail in New York and his head is meowing in Los Angeles. Do you understand this? And radio operates exactly the same way: you send signals here, they receive them there. The only difference is that there is no cat." - Einstein

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