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{
    "url": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/email/Z55DPMUG7JBI5T4CP2QAXDO472BTNFUX/?format=api",
    "mailinglist": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/?format=api",
    "message_id": "CAN6TEUesOuHiYtEwm-GS1oTWehcJ17E=jrYSrnRaFJQmQp2V9Q@mail.gmail.com",
    "message_id_hash": "Z55DPMUG7JBI5T4CP2QAXDO472BTNFUX",
    "thread": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/thread/Z55DPMUG7JBI5T4CP2QAXDO472BTNFUX/?format=api",
    "sender": {
        "address": "amsat-bb (a) wd9ewk.net",
        "mailman_id": "21664df01bef4757931b7cdb42a9e768",
        "emails": "https://mailman.amsat.org/hyperkitty/api/sender/21664df01bef4757931b7cdb42a9e768/emails/?format=api"
    },
    "sender_name": "Patrick STODDARD (WD9EWK/VA7EWK)",
    "subject": "[amsat-bb] AO-85 and TH-D72A, full-duplex? Yes, of course!",
    "date": "2015-11-28T05:24:49Z",
    "parent": null,
    "children": [],
    "votes": {
        "likes": 0,
        "dislikes": 0,
        "status": "neutral"
    },
    "content": "Hi!\n\nI have been trying some Chinese-made dual-band HTs, seeing how well they\nwork with AO-85 full-duplex. I have tried 4 of those radios recently, and\nhave posted my observations in a series of messages here on the AMSAT-BB\nlist. Earlier this afternoon, I did the same with a non-Chinese HT, the\nKenwood TH-D72A. I had no concerns about this radio's ability to work AO-85\nfull-duplex, but I wanted to try it and confirm this for myself.\n\nI have had my TH-D72A since it went on sale at the local HRO store in late\n2010. Over the past (almost) 5 years, I have upgraded its firmware, used it\nto make QSOs on various FM and packet/APRS satellites, and used it for APRS\non my road trips. It's a great radio, although it is among the most\nexpensive 2m/70cm FM HTs in current production. This was a reason why I\nhave been interested in trying other HTs, seeing if there were any\nalternatives to the TH-D72A for full-duplex operation on AO-85 and the\nother upcoming Fox-1 satellites - and especially if they cost less than the\nTH-D72A.\n\nOK, the obligatory question and answer. Can the TH-D72A work AO-85 full-\nduplex?\n\nYES!\n\nUnlike with the Chinese-made HTs, the TH-D72A does not have the 2.5 kHz\ntuning step. Since the TH-D72A doesn't appear to have the sharp receive\nfiltering I have seen with the Chinese-made HTs, this is not an issue. I\ncan leave the TH-D72A's downlink VFO on 145.980 MHz for almost the entire\npass, with a quick change to the next lower tuning step (145.975 MHz) for\nthe last few minutes of the pass. I did not use narrow FM on either VFO\nfor this pass. Based on what I saw with the other HTs, I would only\nconsider using narrow FM on the downlink VFO if the receive audio sounded\nbad. The downlink audio sounded OK in \"normal\" FM today. Another difference\nfrom the Chinese-made HTs is that the uplink VFO must be VFO B (the lower\nVFO) on the TH-D72A. This is the only way to activate the DUP function,\nwhich allows the HT to receive on VFO A while transmitting on VFO B, when\nthese frequencies are in different bands.\n\nOther commonly used settings like transmitting the 67.0 Hz CTCSS tone from\nVFO B, tighten the squelch on VFO B while opening the squelch on VFO A,\nand balancing the audio so you only hear VFO A (menu 120) made it easy to\nknow I am only hearing audio from the downlink VFO (VFO A). If needed, I\ncould have set the downlink VFO (VFO A) to receive in narrow FM (NFM) with\nmenu setting 131, while transmitting from VFO B in \"normal\" FM (FM).\n\nI used an audio splitter in the TH-D72A's speaker jack, feeding audio to an\nearpiece and my Sony audio recorder. This recording is an MP3 file, which I\nput in my Dropbox space along with a larger WAV file (RF recording from\nHDSDR) and other files related to this pass. These files are available from\nmy Dropbox space at http://dropbox.wd9ewk.net/ (look for the folder named\n\"20151127-AO85_Fox1A-DM43\"). This way, anyone can compare the recordings\nfrom this radio against the other recordings I've posted from testing the\nother Chinese-made HTs.\n\nThe AO-85 pass this afternoon around 2226-2240 UTC had a series of resets,\nbut I was able to complete 3 QSOs - AA5PK in west Texas, K8YSE/7 not far\nfrom me in the Phoenix area, and VE6SMI in Alberta. I had no problems\nhearing myself while transmitting, and my transmit audio sounded good -\nfrom the TH-D72A, and from my SDR receive setup I had in my yard (SDRplay\nSDR receiver, HDSDR on an 8-inch Windows 10 tablet, AMSAT-UK VHF crossed\ndipole on an 8-foot mast and tripod).\n\nThe fact I could use a TH-D72A to work AO-85 is no surprise to me. Even\nwith having to quickly switch VFOs to adjust the downlink frequency, then\nswitching back to the uplink VFO before transmitting, is not a problem.\nNone of the HTs I have tested recently have separate knobs for volume,\nsquelch, and tuning for each VFO. This radio would be number 1 on my list\nof HTs I have used to work AO-85 full-duplex, going on top of all of the\nChinese-made HTs I have tried in the past few weeks.\n\nWith the TH-D72A, I have a radio capable of working V/U and U/V FM\nsatellites full-duplex. I also have a radio capable of packet and APRS, and\nI have used mine to make packet QSOs through the ISS, NO-44, and NO-84 when\nits packet/APRS digipeater was active earlier this year. It is nice to have\nat least two options for HTs in current production that can work AO-85\nfull-duplex (TH-D72A, Wouxun KG-UV9D), along with many other HTs that\naren't in production but are also capable of working satellites like AO-85\nfull-duplex.\n\nNow, it's time to find my old Icom IC-W32A in my garage, and maybe even an\nAlinco DJ-G7T I think I still have. I'm not worried about the IC-W32A and\nits ability to work AO-85 full-duplex, as it handled the ISS cross-band\nU/V repeater fine in the mid- to late-2000s. It would be interesting to\ntry the DJ-G7T on AO-85. The DJ-G7T was a very poor performer when I tried\nto use it to work AO-27 and AO-51 full-duplex, satellites with stronger\ndownlinks than SO-50. If I find these radios and can try them on AO-85\npasses, I'll post reports for each of them.\n\n73!\n\n\n\n\n\nPatrick WD9EWK/VA7EWK\nhttp://www.wd9ewk.net/\nTwitter: @WD9EWK\n",
    "attachments": []
}