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{
    "url": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/email/YHCPODSHHWL5WZQ6HXONIKFR6FIYF6RY/?format=api",
    "mailinglist": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/?format=api",
    "message_id": "000801c7c823$6d1b8880$0301a8c0@Shop",
    "message_id_hash": "YHCPODSHHWL5WZQ6HXONIKFR6FIYF6RY",
    "thread": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/thread/RQX4DLDIYY3MVVVNFRFO357N5UXLTUIQ/?format=api",
    "sender": {
        "address": "juan-rivera (a) sbcglobal.net",
        "mailman_id": null,
        "emails": null
    },
    "sender_name": "Juan Rivera",
    "subject": "[eagle]  CAN-Do Suggestions from Juan",
    "date": "2007-07-17T03:34:47Z",
    "parent": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/email/5YA6YAI2PSWNKEE6HB2G35KZADZCBGUN/?format=api",
    "children": [
        "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/email/5THGYUUWQ76VZA6OXHPT37KUVLDSJTL5/?format=api"
    ],
    "votes": {
        "likes": 0,
        "dislikes": 0,
        "status": "neutral"
    },
    "content": "Chuck,\n\nMy comments might have been buried in the flurry of email a while back.\nThings seem a bit quieter now so here they are:\n\n1) Don't get too far into a redesign until a top-level EMI requirement is\ncreated.  This can't be done properly until prototype solar panel power\nconverters are fabricated and tested.  I would work to create a new power\nsupply with a switching frequency of at least 500 kHz while you wait\nhowever.  This will make filtering much easier, the filter components will\nbe smaller, and any spurs that make it into the receiver will be outside the\npassband of the IF.\n\n2) The EMI requirements for radiated and conducted emissions and\nsusceptibility should flow out of that test data and not be guesses.\n\n3) Once we have an EMI requirement then tradeoffs need to be considered\nbetween the CAN-Do module and the enclosure - one or two compartment?  Sheet\nmetal or milled construction?  The results of that tradeoff study will\ndetermine how much room you have to work with, how much front panel space,\nand how much shielding and filtering are required.\n\nIf I had my way the enclosure would be a two-cell milled enclosure with all\nthe RF and IF exiting out the side of the rear cell.  The CAN-Do module and\nthe Receiver switching power supply would both be located in the first cell\nwith feed-thru filtering in the common bulkhead between cells (all digital\npower in the front and all analog in the rear).  That would mean that the\nCAN-Do connector would be the only connector on the front of the case.  If\nthat were true then the only reason to change connectors would be to save\nweight or increase reliability.  It would also mean that the existing CAN-Do\nPCB footprint would be fine as it is.\n\nIn my presentation I will suggest that the next revision of the 70 cm\nreceiver should be postponed until all of these issues are resolved.\n\n73,\n\nJuan\n\n\n\n-----Original Message-----\nFrom: [email protected] [mailto:[email protected]] On Behalf Of\nChuck Green\nSent: Monday, July 16, 2007 7:47 PM\nTo: Louis McFadin\nCc: Dave Black ((Work)); Dave Black ((Home)); David Smith; AMSAT Eagle;\nSamsonoff@Mac. Com; Juan.Rivera ((Work))\nSubject: [eagle] Re: CAN-Do-Too! ??????????\n\nThanks, Lou.\n\nI don't know of any reason not to use them either.  Obviously, it needs \nto meet our mounting configuration requirement so the new mechanical \ndesign can meet the objectives I stated earlier.  This means it must \nmount on the edge of a PCB.  I think the HD15-D has three rows of pins \nso I'm not sure how this can work, but I haven't looked at the various \nparts available so maybe this problem has been solved.\n\nIf we are going to seriously consider using HD connectors I think we \nneed the blessing of AMSAT's VP of Engineering and the EAGLE project \ncoordinator.  This would be true for any change that would be pervasive \nin the satellite. \n\nI am a little disappointed that there have not been any comments \nregarding the changes I saw as being made with a new design.  \nAdditions/changes/questions/etc.  I don't think we should do a new \ndesign without this discussion.  Maybe people feel these issues have \nbeen well covered in the past.  If so, a simple \"looks good to me\" would \nbe helpful.\n\nAnd no one has stepped up to say they are well qualified and will design \na new power supply.  Without this, I don't see a new design happening, \nbut maybe.\n\nAnd finally, I see that no one has dared touch the subject of parts \nprocurement I raised. \n\nObviously, most of these comments are really meant for the Cc list.\n\nThanks,\nChuck\n\nLouis McFadin wrote:\n> Chuck,\n> Mouser has a very large selection of D-sub connectors including the \n> high density versions. Most are in stock.\n> I see no inherent reason for not using them.\n>\n> Lou McFadin\n> W5DID\n> [email protected] <mailto:[email protected]>\n>\n>\n> On Jul 16, 2007, at 7:19 PM, Chuck Green wrote:\n>\n>> I have had one experience with the high density D connectors.  They \n>> were much larger pin count than 9 or 15!  After someone absolutely \n>> insisted that we use them I did the board lay out.  Turned out that \n>> they were *totally* unavailable!!!  I did the board layout \n>> again@#$%&^* using standard Sub-D's.  That was a number of years ago \n>> so I would hope things have changed.  If someone is absolutely \n>> confident they can obtain the parts we need then I'm not at all \n>> opposed to using them (remember, I'm not volunteering to do parts \n>> procurement for this project; this is a good time to use someone \n>> that's good at parts procurement).\n>>\n>> While at Goddard for P3D vib test I noticed NASA satellites using \n>> standard Sub-D's.  That was also a few years ago.  Anyone know of \n>> High Density Sub-D's being used on other satellites?\n>>\n>> Chuck\n>>\n>> Bdale Garbee wrote:\n>>> On Tue, 2007-07-10 at 09:02 -0700, Chuck Green wrote:\n>>>\n>>>   \n>>>> The sub-miniature D connector series has served us well.  If anyone \n>>>> has *experience* with something they think might be a better \n>>>> choice, we'd love to hear about it.\n>>>>     \n>>>\n>>> At the AMSAT annual meeting that was held near Washington, D.C., a\n>>> couple of years ago (three?), someone approached me after the CAN-Do!\n>>> talk that Stephen and I gave to ask why we weren't using the\n>>> higher-density connectors that put 15 pins in the same shell size as the\n>>> 9-pin version of the series we have been using... and followed up by\n>>> sending me what looked like mil/aero-spec samples of such a part that I\n>>> probably still have in my basement somewhere.  I'm sorry that I can't\n>>> recall at all who that person was, but it was someone who claimed to be\n>>> using such connectors professionally with good results.\n>>>\n>>> At the time, we weren't likely to be redesigning the units any time\n>>> soon, so I didn't take any action on this suggestion.  If we're going to\n>>> revisit the design and think we need more than 9 pins, it might be worth\n>>> investigating higher density connectors like that?\n>>>\n>>> Bdale\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",
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