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{ "url": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/email/HKN3T6S67WXX2YU66SBAQANZXLK4LFWW/?format=api", "mailinglist": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/?format=api", "message_id": "000c01c7b133$bd015ca0$0301a8c0@Shop", "message_id_hash": "HKN3T6S67WXX2YU66SBAQANZXLK4LFWW", "thread": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/thread/JELMZYQ4H7LHRQXG74PW5HRJJ5OPPCCL/?format=api", "sender": { "address": "juan-rivera (a) sbcglobal.net", "mailman_id": null, "emails": null }, "sender_name": "Juan Rivera", "subject": "[eagle] Re: EMI Concerns", "date": "2007-06-17T23:03:35Z", "parent": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/email/B6OVQZSWH56LNVCU5KZPR3QGWYULPKHJ/?format=api", "children": [], "votes": { "likes": 0, "dislikes": 0, "status": "neutral" }, "content": "Hello Bill,\n\n \n\nI have been keeping logs on the 70 cm receiver construction and testing as\nwe progress from the first prototype to the first set of non-flight units.\nLot's has happened in the past few months. You can find them all on\nEaglePedia if you'd like some light reading.\n\n \n\nWe now have one prototype running in my shop, with a few remaining problems\nto fix. Then John is going to redesign the radio and my group will\nfabricate four units. We are getting close to that point now. John has\nreleased a new preliminary specification which is on Eaglepedia for review\nand comments. There is nothing in this new spec about EMI. Based on what\nI'm seeing I think this needs to be hammered out before we start ordering\nparts. I just went back and revised my last log to include a few links to\nEMI surface mount filters in automotive applications. This might be a good\nplace to start looking for a fix.\n\n \n\nAnyway, the main issue at hand right now, in my humble opinion, is this:\nThe CAN-Do module, which is to be an integral part of every payload on\nEagle, and mounted INSIDE the payload chassis, ON THE PCB, produces copious\nquantities of radiated and conducted noise. I had to move the receiver PCB\n2-1/4 inches away from the CAN-Do module to escape the radiated noise, and\nrun independent power around the CAN-Do module's normal switched +14 to\nescape the conducted noise. This is not a good thing! I think that bad boy\nneeds to be quieted down somehow.\n\n \n\nIf you can come up with an interface control document that addresses these\nissues I think that would be an excellent step in the right direction!\n\n \n\n73,\n\n \n\nJuan\n\n \n\n _____ \n\nFrom: Bill Tynan [mailto:[email protected]] \nSent: Sunday, June 17, 2007 2:56 PM\nTo: [email protected]; 'Bdale Garbee'\nCc: 'David Smith'; 'Dave Black (Work)'; 'Dave Black (Home)';\[email protected]; 'Samsonoff@Mac. Com'; 'Juan.Rivera (Work)'\nSubject: Re: [eagle] Re: 70 cm Eagle Receiver - Final Spur Report (at least\nfortoday...)\n\n \n\nRight On Juan:\n\n \n\nHere is where an interface document is a nesessity. That's what I told Jim I\nwould undertake. But, I have been out of the Eagle loop for months and thus\ndidn't know that such issues were now coming up.\n\n \n\nAn interface document should spell out power, including power quality, not\nmere pin connections and physical fit data.\n\n \n\nI have a lot of catching up to do but will need a lot of help to get\nstarted.\n\n \n\n73,\n\n \n\nBill Tynan, W3XO\n\n----- Original Message ----- \n\nFrom: Juan <mailto:[email protected]> Rivera \n\nTo: 'Bdale Garbee' <mailto:[email protected]> \n\nCc: 'David Smith' <mailto:[email protected]> ; 'Dave\n<mailto:[email protected]> Black (Work)' ; 'Dave Black (Home)'\n<mailto:[email protected]> ; [email protected] ; 'Samsonoff@Mac.\n<mailto:'Samsonoff@Mac.%20Com'> Com' ; 'Juan.Rivera (Work)'\n<mailto:[email protected]> \n\nSent: Sunday, June 17, 2007 12:58 PM\n\nSubject: [eagle] Re: 70 cm Eagle Receiver - Final Spur Report (at least\nfortoday...)\n\n \n\nBdale,\n\n \n\nI certainly wouldn't suggest that no one in AMSAT understands power\ndistribution. I just can't find any detailed requirements. What I have\nfound was a spreadsheet (click\n<http://www.amsat.org/amsat-new/eagle/EaglePedia/uploads/1/14/Wiring.xls>\nhere) that lays out all of Eagle's wiring. There is no mention of shielding\nor twisted pairs for the power. Both are important to reduce radiated\nnoise.\n\n \n\nAs a newcomer I am wary of aural tradition and informal meetings as good\ntools for development of complex systems. I think everything needs to be\nwritten down in unambiguous requirements documents, starting at the top\nlevel. This current exercise with the 70 cm receiver is a good test of the\ncurrent processes and procedures.\n\n \n\nI've glanced at John's new receiver specifications and I don't see any\nreference to input power or the EMI environment that the receiver must work\nin. How can it be designed or tested if that environment has not been\nspecified as a requirement? It's not John's fault. He has nothing to base\nit on. That's where the top level requirements would give him something to\nwork with. Everything needs to start at the top and work down. Not from\nthe bottom up.\n\n \n\n73,\n\n \n\nJuan\n\n \n\n \n\n \n\n \n\n \n\n-----Original Message-----\nFrom: Bdale Garbee [mailto:[email protected]] \nSent: Sunday, June 17, 2007 10:04 AM\nTo: [email protected]\nCc: [email protected]; David Smith; Dave Black (Work); Dave Black (Home);\nSamsonoff@Mac. Com; Juan.Rivera (Work)\nSubject: Re: [eagle] 70 cm Eagle Receiver - Final Spur Report (at least\nfortoday...)\n\n \n\nOn Sun, 2007-06-17 at 08:48 -0700, Juan Rivera wrote:\n\n \n\n> I've completed my testing and analysis of the spurs that appeared in\n\n> the IF output of the 70 cm Eagle Receiver prototype. I believe I know\n\n> the source and the cause of all of them and how they can be eliminated\n\n> or rendered harmless.\n\n \n\nNice work.\n\n \n\nReading your report, two things strike me, neither of which I consider\n\nmyself an expert on in AMSAT or elsewhere, but both of which I'll\n\nmention to help motivate the review of power system requirements you\n\nclearly hope comes next/soon. \n\n \n\nThe first is that I think AMSAT does understand most if not all of the\n\nissues you're warning against regarding DC distributiong wiring. Some\n\ncare was taken, for example, in planning pinouts of the 15-pin connector\n\non the spacecraft bus side of the CAN-Do! widget, and in the proposed\n\nwiring harness design from the Black Forest meeting.\n\n \n\nThe second is that I think more work is going to be required to ensure\n\nreceivers behave reasonably in the presence of supply noise. For\n\nvarious reasons, as others have already alluded, I wouldn't count on the\n\nEagle power bus being very quiet.\n\n \n\nBdale, from Edinburgh\n\n \n\n \n\n \n\n \n\n \n\n \n\n\n _____ \n\n\n_______________________________________________\nVia the Eagle mailing list courtesy of AMSAT-NA\[email protected]\nhttp://amsat.org/mailman/listinfo/eagle\n\n\n\n", "attachments": [ { "email": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/email/HKN3T6S67WXX2YU66SBAQANZXLK4LFWW/?format=api", "counter": 2, "name": "attachment.html", "content_type": "text/html", "encoding": "us-ascii", "size": 21630, "download": "https://mailman.amsat.org/hyperkitty/list/[email protected]/message/HKN3T6S67WXX2YU66SBAQANZXLK4LFWW/attachment/2/attachment.html" } ] }