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{
    "url": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/email/TLBB5KQBWNXJT7SOYHXYYXKSHH5S5M6W/?format=api",
    "mailinglist": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/?format=api",
    "message_id": "[email protected]",
    "message_id_hash": "TLBB5KQBWNXJT7SOYHXYYXKSHH5S5M6W",
    "thread": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/thread/TLBB5KQBWNXJT7SOYHXYYXKSHH5S5M6W/?format=api",
    "sender": {
        "address": "ka3hdo (a) comcast.net",
        "mailman_id": "fa8edbc3567d4116ab189c93e04bdde1",
        "emails": "https://mailman.amsat.org/hyperkitty/api/sender/fa8edbc3567d4116ab189c93e04bdde1/emails/?format=api"
    },
    "sender_name": "Frank H. Bauer",
    "subject": "[amsat-bb]  SSTV Clarification",
    "date": "2009-04-02T20:58:33Z",
    "parent": null,
    "children": [],
    "votes": {
        "likes": 0,
        "dislikes": 0,
        "status": "neutral"
    },
    "content": "All,\n\nI wanted to clarify some statements made by Miles, based on where ARISS was\nwhen I stepped down.  \n\nIn his e-mail he states:\n\n-----------------------\nSSTV Status:\n\nWe have two SSTV systems on ISS. One is the Kenwood VCH1 sstv microphone.\nThis is the system which th4 crew has been using the most.  The system only\nruns on AA batteries at this time due to flight safety limitations.\n\nThe second system is the Marex Software system called SpaceCam1.  This\nsystem will run manually for fully automatic.  The software system has not\nbeen used much because of a problem with the VOX cable that goes to the D700\ntransceiver.  When the Vox cable is used the radio sticks in the\nTransmitting mode until 3-minute watchdog timer expires.  ARISS has tried\ntwo different cables with the same results.  The Vox gets its power from the\nD700 and it appears the dc power has too much RF and is causing Vox circuit\nto keep the radio stuck transmitting.\n\nMarex is proposing a completely different VOC using that has been tested\nextensively.\n----------------------\n\nThe ARISS-provided VC-H1 currently does run on AA batteries.  The use of AA\nbatteries was not due to flight safety limitations at all.  Given the tight\nschedule that we had for Richard Garriott's flight and the need to fly a\nhardware-based SSTV system, we concentrated on certifying the VC-H1 with the\nunderstanding that there was a surplus of AA batteries on ISS.  On ISS,\nbatteries for critical functions are taken out of service and replaced\nbefore they are fully used up.  These partially-used batteries can easily be\nused for non-critical devices like the VC-H1. The ARISS team is working on a\nbattery eliminator (power supply) for the VC-H1 that will be flown at a\nlater date.\n\nThere are 3 SSTV systems on board, one hardware system (VC-H1) and two\nsoftware-based systems, MMSSTV and SpaceCam.  The primary rationale for\nmaking the VC-H1 prime is that the ARISS team gets very limited use (read\nas: almost no use) of an on-board computer.  So the SSTV operations over the\npast few years was nearly zero.  Only when the VC-H1 was introduced in\nOctober 2008 did SSTV on ISS really take off.  Some self-interference issues\nhave been observed on the software-based system that were not observed on\nthe ground prior to flight. As of right now, it is unclear what is causing\nthis issue.   The ARISS team has not had an opportunity to fully debug this\nissue on-orbit.  (It is very hard to get a computer and the crew time at the\nsame time)  So I would not speculate what the issue is.  Also, there are\nsome subtle differences in the radio system on-board ISS as compared to the\nground-based equivalents.\n\nAny proposals for new amateur radio hardware and software systems need to be\napproved by the ARISS project selection and use committee.  They then need\nto be presented to the space agencies.  The space agencies then determine if\nthere is volume/power/mass available on-board for the system and give the\nARISS team a yes/no answer as to whether they are willing to fly the\nequipment.  The proposal then needs to get a final concurence from the ARISS\ninternational delegates to move forward as an official project.  \n\nMiles' proposal (above) has not gone through that process yet.\n\nI hope this clarifies.\n\n73,  Frank Bauer, KA3HDO \n\n\n",
    "attachments": []
}