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{
    "url": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/email/HISUCPTIVU5F7BVEHBVUERVR2K6FLKVD/?format=api",
    "mailinglist": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/?format=api",
    "message_id": "000c01c7d172$65a7a130$0301a8c0@Shop",
    "message_id_hash": "HISUCPTIVU5F7BVEHBVUERVR2K6FLKVD",
    "thread": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/thread/25226SNLR7JQHI43WH4WBEEYEO5PLXTI/?format=api",
    "sender": {
        "address": "juan-rivera (a) sbcglobal.net",
        "mailman_id": null,
        "emails": null
    },
    "sender_name": "Juan Rivera",
    "subject": "[eagle] Re: Receiver Spec vs. ATP,\ta few Suggestions and aQuestion or Two",
    "date": "2007-07-28T23:52:44Z",
    "parent": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/email/DUPCGLJL2WXM3VS7FFUTV4PFLGZ5O5AD/?format=api",
    "children": [
        "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/email/EVTGC2TNYREWAP7ULLWZLNOKUU3BCWGE/?format=api"
    ],
    "votes": {
        "likes": 0,
        "dislikes": 0,
        "status": "neutral"
    },
    "content": "Hi Chuck,\n\nI don't think that existing supply is running at 90% efficiency.  I'll have\nto solder it back together to take a few measurements but the manufacturer's\nspecs don't claim quite that much and this one isn't running properly.  I've\ngot a bit more data in my symposium presentation and I hope to complete that\nin the next few days and get it out.\n\nI found a step-down converter that's designed to supply a maximum of about\n100 mA and it runs at 400 kHz with automotive temp range.  If no one else\nsteps up I'll put out some info on this one.\n\n73,\n\nJuan\n\n-----Original Message-----\nFrom: Chuck Green [mailto:[email protected]] \nSent: Saturday, July 28, 2007 3:30 PM\nTo: [email protected]\nCc: 'Bdale Garbee'; 'David Smith'; 'Dave Black (Work)'; 'Dave Black (Home)';\[email protected]; 'Samsonoff@Mac. Com'; 'Juan.Rivera (Work)'\nSubject: Re: [eagle] Re: Receiver Spec vs. ATP, a few Suggestions and\naQuestion or Two\n\nHi Juan,\n\nI think the reason you have not seen much regarding the CAN-Do redesign \nis that, as far as I know, no one has stepped up to do the power supply \nredesign.  Until that happens, not much else will happen.\n\nI'm not thrilled with the idea of giving up the switching power supply.  \nRemember that the efficiency hit must be multiplied by 10-15, the number \nof CAN-Do's on the satellite. \n\nThe \"dead-bug\" modification is intended to fly.  Those who were not \naround in the early days have no idea what loose wires have flown \nsuccessfully in the past.  That's not to say we should encourage such \nthings, just that it's not as ugly to those of us who have seen much \nworse in the past as you might think.  Because of the IC's mass (very \nsmall) it is probably very secure just the way you see it.  But we will \nalso epoxy a radiation shield to it and then conformal coat the whole \nthing with a heave conformal coating which will make it very difficult \nfor anything to move.\n\nI'm ready to start a new design (layout) just as soon as someone gives \nus a new power supply design that is quieter, and hopefully, more \nefficient than the 90% we now have.\n\nChuck\n\nJuan Rivera wrote:\n> Bdale,\n>\n> It would be a trade-off.  I've put out all the information I have and\n> everyone knows my opinions.  I think someone else is supposed to be\nlooking\n> into this but I forgot who it is since nothing has been posted.  I'd like\nto\n> see some alternative suggestions from the experts on the CAN-Do, the\n> enclosure, and the EMI situation in general.\n>\n> By the way, do I have a prototype CAN-Do module or was the intent to fly\n> this version with the dead-bug step-down converter hanging by three leads\n> and a few wires?\n>\n> Juan\n>\n> -----Original Message-----\n> From: Bdale Garbee [mailto:[email protected]] \n> Sent: Saturday, July 28, 2007 2:41 PM\n> To: [email protected]\n> Cc: 'John B. Stephensen'; David Smith; Dave Black (Work); Dave Black\n(Home);\n> [email protected]; Samsonoff@Mac. Com; Juan.Rivera (Work)\n> Subject: Re: [eagle] Receiver Spec vs. ATP, a few Suggestions and\naQuestion\n> or Two\n>\n> On Fri, 2007-07-27 at 21:23 -0700, Juan Rivera wrote:\n>\n>   \n>> I have a few thoughts...  The CAN-Do switching step-down converter is\n>> only supplying 11 milliamps.  If we take a slight efficiency hit we\n>> could just go to a simple linear regulator and completely eliminate\n>> the radiated and conducted EMI emission problem from CAN-do.  That\n>> eases the EMI filtering and shielding requirements for every single\n>> payload.  That seems like a good trade-off to me.\n>>     \n>\n> Hrm.  What makes you say \"a slight efficiency hit\"?  \n>\n> Doing this on one or two modules that are particularly susceptible to\n> noise *may* make sense (and I'm certainly open to considering this as an\n> alternative), but we're already on our second power supply design on the\n> CAN-Do! because the original switcher, which was more efficient than a\n> linear regulator, was deemed too inefficient to fly on P3E by our\n> AMSAT-DL friends.\n>\n> Bdale\n>\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\n\n",
    "attachments": []
}