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{
    "url": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/email/UUQ3IDXHDJEE3ZDQ6XPUPKE3BZAMMFCP/",
    "mailinglist": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/",
    "message_id": "[email protected]",
    "message_id_hash": "UUQ3IDXHDJEE3ZDQ6XPUPKE3BZAMMFCP",
    "thread": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/thread/UUQ3IDXHDJEE3ZDQ6XPUPKE3BZAMMFCP/",
    "sender": {
        "address": "K3IO (a) verizon.net",
        "mailman_id": "79a9b3ddaa4b44baae47f92374974ac4",
        "emails": "https://mailman.amsat.org/hyperkitty/api/sender/79a9b3ddaa4b44baae47f92374974ac4/emails/"
    },
    "sender_name": "Tom Clark, K3IO",
    "subject": "[amsat-bb] Re: AO-07 Healthy CW]",
    "date": "2006-11-29T04:30:19Z",
    "parent": null,
    "children": [
        "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/email/2TKAJYATVQZB7XCWBFCVLFUF2TD5C4QR/"
    ],
    "votes": {
        "likes": 0,
        "dislikes": 0,
        "status": "neutral"
    },
    "content": "W9GB noted\n\n>\n> I can identify the lab equipment on the bench (looks like my high\n> school & college labs - 1970s) with the NiCad battery pak, EXCEPT for\n> the rectangular box with metal handles to the right of the NiCads. \n>  \n> NiCad battery charger?   Homwbrew power supply?\nGreg -- the high-priced hardware (HP+Tek) show NASA Goddard property\nlabels. The cheaper power supplies in the back are Heathkits with AMSAT\nstickers.\n\nThe box you are asking about has a yellow Goddard tag. I'm trying to\nrecognize it, and to the best of my recollection it is a Coulomb-meter\nthat measured (on the mechanical counter you see on its panel) the\nintegrated charge/discharge current. Also my fuzzy memory tells me that\nthe heatsink device on clip leads was a prototype BCR.\n\nSil asked:\n> I guess there's a special \"satellite design\" reason that double wires\n> are used (instead of one thicker one) for the current carrying battery\n> leads?\nThe twin wires go to a pair of pins on the DA-9 connector, with two pins\nproviding greater current handling ability and redundancy. It also\nappears that the V/2 telemetry tap has a pair of whit wires even though\nit provided zero current. BTW -- the V/2 telemetry would be on 3B.\n> Leaving aside Geoff's (vk2tfg) point that the telemetry may be\n> irrelevant because of the doggy value in channel 6D, it would seem that\n> the five top cells (between half volt point and +12V - numbers 2,3,4,5,6\n> counting clockwise) are being charged with a current of 80mA and have\n> reached a terminal voltage of 6.4 volts (8.8 - 2.4). This represents a\n> voltage of 1.28 per cell (6.4/5) and is thoroughly reasonable. This idea\n> is supported by the temperature of cell number 5 at 60.28 C. \n\nThe top 5 cells are fed by the black wire and are the LOW voltage side.\nThe 5 \"high side\" batteries terminate in the orange wire on the bottom,\nThe thermistor on cell #5 is on the low voltage side.\n\nThe thermal design of the s/c ended up with internal temps ~20°-30°C\nrange (i.e. TLM values in the 40-50 range). I find it hard to believe\nthat a valid interior temperature would ever be in the 60°C range.\n\nRegarding all the telemetry speculation -- AFAIK, there is no indication\nthat the A/D converter is showing ANY valid data at all -- see also\nJan's comments at http://www.amsat.org/amsat/sats/n7hpr/ao7_tlm.html.\n\nFYI -- the TLM and its associate Morse encoder system was built with\ndiscrete CMOS logic by John Goode, W5CAY in Texas. Memory fails me, but\nI believe that the TLM/Morse board is on the \"back wall\" in the\nphotograph at http://www.amsat.org/amsat/sats/ao7/slideset/slide09.html\neven thought the photo only identifies the module as the command\nencoder. All the white IC's a early RCA ceramic 4000-series parts.\nAFAIK, Oscar-6 & -7 were the first CMOS users in space. AO-7, with much\nof this logic still functioning after 32 years and 2 weeks, certainly\nholds the longevity record!\n\n[In case you forgot, Nov.15th was AO=7's 32nd birthday -- my favorite\npicture of the launch is the \"7-UP\" contrail left by the Delta booster\nhttp://www.amsat.org/amsat/sats/ao7/slideset/slide18.html]\n\n73, Tom\n\n\n\n\n\n\n\n",
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