March 2007 - Eagle (INACTIVE) - mailman.amsat.org

Major Eagle events
by Jim Sanford 12 Apr '07

12 Apr '07

All: I send this separate note to advise you of some major developments with Eagle. Many of you are already aware of them, but in case I missed someone, I send this separate update. Two nights ago, I authorized expenditure of funds for purchase of components and construction of four prototypes of the UHF receiver designed by John Stephenson, KD6OZH. The boards will be distributed as follows: one to Juan Rivera, WA6HTP, for Acceptance Testing followed by limited vacuum and thermal testing one to be demonstrated at Dayton one to the SDX folks for their development one to be put through the ATP either here by me, or wherever anyone else wants to evaluate. This will then become available as needed for demonstrations or SDX development Events leading to this decision: Design by John and Peer review Development of ATP by Juan and peer review Assembly of a procurement, construction, and test team of Project Oscar members under Juan's leadership PCBoard layout by John. Peer review of schematic to board correlation in progress Development of costed Bill of Materials (BOM) by the Project Oscar team. This was a LOT of work, and actually resulted in some tweaks to design and component selection Peer review of the BOM in progress I have authorized $4100 for this effort. A small fraction of this cost includes consumables for surface mount construction and some assembly tools which will become AMSAT property and will be used again. AMSAT costs were reduced by a significant amount of "scrounging." I submitted some of this information for publication in ANS, but don't yet know if I was ahead of the deadline or not.. If I was late, I hope it will appear next week. This seems to me a huge step. We have completed one design cycle on one component and are now about to transition, for that one component, from the concept exploration/definition phase into construction of hardware. Prototype hardware, yes, but we will soon have some real test results and something real to show. The short list above belies a whole lot of work by a whole lot of folks, alll of whom I thank. Many of you participated in the earlier reviews of John's design and Juan's ATP. The near-frantic effort over the last few weeks by John and the Project Oscar folks (many of whom I'm just getting to know through various emails and echolink conferences) has been intense. As we progress with procurement and construction, I will receive and share progress updates as major milestones are met. The documents mentioned above are not all on EaglePedia yet, but will be. In particular, one unexpected fallout of the recent efforts is a BOM which may be a good template for other teams to use. It certainly made it easy for me to see and understand, "how many, how much?" Thank you all. Very 73, Jim wb4gcs(a)amsat.org

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Re: Eagle Microwave Antenna Arrays -- mechanical concepts
by Tom Clark, K3IO 03 Apr '07

03 Apr '07

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Personal planning
by Jim Sanford 28 Mar '07

28 Mar '07

All: For your information, I provide some information regarding my status and forthcoming availability. My day job is getting busier. As a result of a bunch of things, I'm now the manager of what we'll call "shipboard automation." This means I have tentacles in all hardware, OS infrastructure, and custom applications being developed for the shipboard areas I care about. There are many things going on, but not necessarily well. Part of my mission is to herd the cats, set some priorities, and get some stuff done -- enough churn. I'll be attending "targeted selection" training for the next 2 days. TS is an interviewing technique, and there is a need for my assistance in interviewing candidates. Yeah, I know, there are millions, and it's not different from what I've done before, but training is training. I will be out of pocket the next two days, but briefly available in the evenings. (Obvious conclusion: I would welcome resumes from engineers seeking employment in the Pittsburgh area.) Starting Sunday (1 Apr), I'll be at Bechtel Project Management training for a week. I'm very excited about this -- Bechtel routinely does things that very few organizations in the world can do, on time, in budget, and without getting anybody hurt. This tremendou educational opportunity has been in the works for over a year. I'll have the laptop with me and access to email, but it will be after long days and several hours of homework each night. So, I'll be reachable, but in a limited/delayed way. This is a good thing, I'm SURE I'll get things out of this which will help me help Eagle. Bottom line: Don't stop sending me anything, just recognize that my responses may be delayed. We are within hours of authorizing construction of UHF receiver prototypes -- that work will be my highest AMSAT priority. Thanks & 73, Jim wb4gcs(a)amsat.org

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New Microwave IPA
by Tom Clark, K3IO 27 Mar '07

27 Mar '07

MIMIX has just announced some 2 stage moderate power (+20dBM 1dB compression, 23 dB gain, 4-21 GHz) Intermediate Power Amps that look interesting. They talk in terms of small 3x3 QFN SMT footprints. See http://www.mimixbroadband.com/PR/PR_022607.html for press release info. Anyone know anything about these parts? 73, Tom

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Power bus voltage
by John B. Stephensen 24 Mar '07

24 Mar '07

My current understanding of the DC power bus is that it is driven by banls of 4 Lithium-ion cells. These normally provide 2.7-3.6 V per cell but have 4.2V across them during charging at the end of the charging cycle. This would mean that the DC power bus in Eagle is 10.8-16.8 VDC. I don't see this documented in EagePedia. Is this correct? 73, John KD6OZH

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TeamSpeak conference for Tuesday 13 Feb
by Jim Sanford 23 Mar '07

23 Mar '07

Team: Our next TS conference will be Tuesday night at 2100 EST, 1800 PST, 0200 ZULU. The agenda is posted on the TeamSpeak conferences page of EaglePedia. Please add to it and join us Tuesday night. Note: I'll be travelling to VA and the weather is looking ugly (to be kind), so I might be a few minutes late. If I don't show up, please press on and take good notes. Thanks & 73, Jim wb4gcs(a)amsat.org

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High Efficiency Linear Amplifiers
by Tom Clark, K3IO 21 Mar '07

21 Mar '07

A message sent to the SoftRock40 news group led to an interesting discovery. There is an interesting 4-part series in the journal "High Frequency Electronics" that is a tutorial on various techniques to achieve high efficiency power amplifiers. The article mentions the Doherty technique from the 1930's which was the progenitor of Meinzer's HELAPS. To fetch the series, surf to http://www.rfcafe.com/references/magazine_articles/magazine_articles_2003.h… which leads to the 4-part article "RF & Microwave Power Amplifier & Transmitter Technologies". 73, Tom

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Eagle theme for Dayton
by Gould Smith 21 Mar '07

21 Mar '07

I am working on a theme about Eagle for Dayton. What I have now is "The Eagle Build Begins". I am looking for other suggestions, so bring them on. This will go on a banner at the center of the booth and in the Eagle area. Let me know by Thursday evening, EDT. Thanks, Gould

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information request
by Jim Sanford 17 Mar '07

17 Mar '07

Team: I have received a response on my info request, thanks! 73, JIm

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IEEE information request
by Jim Sanford 17 Mar '07

17 Mar '07

Team: I think I remember someone on here saying that they had access to the IEEE library. I'm seeking an article, W. C. Williams, "Reliability: Lessons from NASA,": IEEE Spectrum Vol 18 No 10, Oct 1981, pp 79-84. This is referrenced in the Davidoff book. As a member, I'm supposed to be able to get a free 30 day trial, for which I've signed up, but it will be some number of working days. If any of you already have access & could get me this article, I'd appreciate it. Thanks & 73, Jim wb4gcs(a)amsat.org

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