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{
    "url": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/email/SVPUZFL5TFTBIDUOEIBDS7F3SH3B7F5C/",
    "mailinglist": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/",
    "message_id": "[email protected]",
    "message_id_hash": "SVPUZFL5TFTBIDUOEIBDS7F3SH3B7F5C",
    "thread": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/thread/SVPUZFL5TFTBIDUOEIBDS7F3SH3B7F5C/",
    "sender": {
        "address": "stanwa1ecf (a) verizon.net",
        "mailman_id": "95c2e52bcb99492e9fc868e42f9e2eb3",
        "emails": "https://mailman.amsat.org/hyperkitty/api/sender/95c2e52bcb99492e9fc868e42f9e2eb3/emails/"
    },
    "sender_name": "Stan,WA1ECF",
    "subject": "[amsat-bb]  External sequencer with the IC-910H",
    "date": "2006-09-04T17:01:47Z",
    "parent": null,
    "children": [],
    "votes": {
        "likes": 0,
        "dislikes": 0,
        "status": "neutral"
    },
    "content": "Hello the NET:\n\nA sequencer is needed to properly transition the PA, IPA, transverter, \ntransceiver, and preamplifier\nwhen going from RX to TX and TX to RX.\n\nThe objective is to add a very short  time delay to avoid sending QRO RF \npower into the preamplifier\nor into an open, just closing relay contact, like \"hot switching\" which \nsignificantly reduces contact life.\n\nI use my IC-706MK2 transceiver with a Lunar Link QRO amp for terrestrial \nmodes.\n\nThese techniques are applicable to any transceiver, PA, IPA preamp \nconfiguration.\nJust different microphone connectors are used.\nI apply the same techniques to the FT-847 and the FT-1000MP (IF rig).\n\nDEMI offers a sequencer kit at about 35$US, Advanced Receiver Research, \nSSB,\nJWM engineering, LNA technologies, W1GHZ, and others also offer non kit \nversions.\nThe DEMI design uses relays with a 2 amp contact rating, others can be \nmuch less.\nAll have their unique variations.\n\nI grab the microphone PTT line, before it gets to the radio, route it to \nthe sequencer input,\nthen take the sequenced outputs:\nDC power to the preamp and bypass RF relays, 2 each SPDT legal limit \nrated RF relays\nPTT, ground to TX,  to the QRO PA,\nPTT, ground to TX,  to the IPA (or transverter)\nPTT ground to TX, to the transceiver\n\nFor RX to TX,\npreamp and transfer relay power is dropped, bypassing the preamplifier\ntime delay ~ 250 milliseconds in the unmodified DEMI sequencer\nPA  TX is enabled\ntime delay, ~ 250 milliseconds\nIPA/transverter TX is enabled\ntime delay, ~ 250 milliseconds\ntransceiver TX is enabled for SSb , CW, FM, whatever modulation\n\nThis timing constant, in the DEMI sequencer, is a RC network and can be \nmodified for a faster\ntime delay.\n\nFor TX to RX, The sequence is reversed.\nSome sequencers simultaneously change all output states, without a \nsequenced delay.\n\nMost sequencers allow enough flexibility to configure PTT ground to TX, \nor PTT +V to TX\nMostly with \"dry\"relay contact closures for a real 0.00V on grounding, \nunlike a solid state switch.\n\nI put the sequencer in a diecast box with a 4 pole multi position \nmechanical switch to route the sequencer outputs.\npole #1 is for local indicator LEDS to show what band I am controlling.\npole #2 for the preamp/bypass relay power\npole #3 for the PA PTT control\npole #4 for the IPA/transverter PTT control\n\nThe transceiver PTT is always the same, and not switched. Your \nconfiguration may vary.\n\nAvoid any break in CW keying. always force TX mode (with a manual PTT \nswitch), before using CW\n\nOne switch position per band.\n\nStan, W1LE  FN41sr   Cape Cod\n\n\n\n\n",
    "attachments": []
}