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{
    "url": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/email/WNQJOY2WFYRL4ZKVAABJFL2WOPQP6TH7/?format=api",
    "mailinglist": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/?format=api",
    "message_id": "[email protected]",
    "message_id_hash": "WNQJOY2WFYRL4ZKVAABJFL2WOPQP6TH7",
    "thread": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/thread/JELMZYQ4H7LHRQXG74PW5HRJJ5OPPCCL/?format=api",
    "sender": {
        "address": "bill (a) hsmicrowave.com",
        "mailman_id": "d7ecbf0c1df148f289f27dd7a8c37974",
        "emails": "https://mailman.amsat.org/hyperkitty/api/sender/d7ecbf0c1df148f289f27dd7a8c37974/emails/?format=api"
    },
    "sender_name": "Bill Ress",
    "subject": "[eagle] Re: 70 cm Eagle Receiver - Final Spur Report (at least for\ttoday...)",
    "date": "2007-06-17T18:52:38Z",
    "parent": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/email/E256LS7HVTXLZEZK73B3VQ5LPDM7HWAU/?format=api",
    "children": [
        "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/email/KSW2M726QBTFQYW66ZWEAPFPADKLTL65/?format=api"
    ],
    "votes": {
        "likes": 0,
        "dislikes": 0,
        "status": "neutral"
    },
    "content": "Hi Juan.\n\nI will add my second to that, not that I haven't already harped on this \nsubject.\n\nAlong with trying to specify what the DC power to the receiver and \ntransmitter modules might look like (a written down good guess based on \npast satellites would even be a place to start) - we also need to define \nwhat the 10MHz reference phase noise will look like. It's really tough \ncommitting to build LO's when you aren't certain what the reference will \nlook like.\n\nMatt Ettus asked the same question about the 10 MHz reference several \nweeks ago but I haven't seen a Eagle thread response (perhaps Matt got \nhis answer off thread).\n\nJuan Rivera wrote:\n>\n> Bdale,\n>\n> I certainly wouldn't suggest that no one in AMSAT understands power \n> distribution. I just can't find any detailed requirements. What I have \n> found was a spreadsheet (click here \n> <http://www.amsat.org/amsat-new/eagle/EaglePedia/uploads/1/14/Wiring.xls>) \n> that lays out all of Eagle’s wiring. There is no mention of shielding \n> or twisted pairs for the power. Both are important to reduce radiated \n> noise.\n>\n> As a newcomer I am wary of aural tradition and informal meetings as \n> good tools for development of complex systems. I think everything \n> needs to be written down in unambiguous requirements documents, \n> starting at the top level. This current exercise with the 70 cm \n> receiver is a good test of the current processes and procedures.\n>\n> I’ve glanced at John's new receiver specifications and I don’t see any \n> reference to input power or the EMI environment that the receiver must \n> work in. How can it be designed or tested if that environment has not \n> been specified as a requirement? It’s not John’s fault. He has nothing \n> to base it on. That’s where the top level requirements would give him \n> something to work with. Everything needs to start at the top and work \n> down. Not from the bottom up.\n>\n> 73,\n>\n> Juan\n>\n> -----Original Message-----\n> From: Bdale Garbee [mailto:[email protected]]\n> Sent: Sunday, June 17, 2007 10:04 AM\n> To: [email protected]\n> Cc: [email protected]; David Smith; Dave Black (Work); Dave Black \n> (Home); Samsonoff@Mac. Com; Juan.Rivera (Work)\n> Subject: Re: [eagle] 70 cm Eagle Receiver - Final Spur Report (at \n> least fortoday...)\n>\n> On Sun, 2007-06-17 at 08:48 -0700, Juan Rivera wrote:\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> Nice work.\n>\n> Reading your report, two things strike me, neither of which I consider\n>\n> myself an expert on in AMSAT or elsewhere, but both of which I'll\n>\n> mention to help motivate the review of power system requirements you\n>\n> clearly hope comes next/soon.\n>\n> The first is that I think AMSAT does understand most if not all of the\n>\n> issues you're warning against regarding DC distributiong wiring. Some\n>\n> care was taken, for example, in planning pinouts of the 15-pin connector\n>\n> on the spacecraft bus side of the CAN-Do! widget, and in the proposed\n>\n> wiring harness design from the Black Forest meeting.\n>\n> The second is that I think more work is going to be required to ensure\n>\n> receivers behave reasonably in the presence of supply noise. For\n>\n> various reasons, as others have already alluded, I wouldn't count on the\n>\n> Eagle power bus being very quiet.\n>\n> Bdale, from Edinburgh\n>\n> ------------------------------------------------------------------------\n>\n> _______________________________________________\n> Via the Eagle mailing list courtesy of AMSAT-NA\n> [email protected]\n> http://amsat.org/mailman/listinfo/eagle\n>   \n\n",
    "attachments": []
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