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{
    "url": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/email/X5WA57RP522KAUWC3FM476PR6JK7NTSZ/",
    "mailinglist": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/",
    "message_id": "[email protected]",
    "message_id_hash": "X5WA57RP522KAUWC3FM476PR6JK7NTSZ",
    "thread": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/thread/X5WA57RP522KAUWC3FM476PR6JK7NTSZ/",
    "sender": {
        "address": "pe1hzg (a) amsat.org",
        "mailman_id": null,
        "emails": null
    },
    "sender_name": "Geert Jan de Groot",
    "subject": "[amsat-bb] Re: Very Interesting Radio - Possible Sat Use (maybe not)",
    "date": "2012-01-13T11:00:24Z",
    "parent": null,
    "children": [
        "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/email/JIEQCTRMNQ2WQMLFSGWMW2BJGQZ5HEJY/"
    ],
    "votes": {
        "likes": 0,
        "dislikes": 0,
        "status": "neutral"
    },
    "content": "\n> I purchased an interesting radio that might be an inexpensive way to\n> operate full duplex on the FM sats.\n> The radio cost $65 including shipping and all accessories. It runs 2W on\n> both 2M and 70cm. It has\n> almost all the bells and whistles you would expect on a dual band handi. 99\n> memories - tone squelch ...\n> http://www.tomdoyle.org/UV-X4.jpg\n\nThere have been various postings and publications in QST and Funkamateur\nabout the brother of this radio, the Baofeng UV-3R, and it's very poor\nharmonics filtering on the 2m band. Harmonic suppression was something\nlike 15-20dB.\nI recently measured an UV-3R mark 1 (single frequency on display)\nand confirmed that the very poor filtering was indeed the case.\n\nSince these things transmit from 136 - 174 I tuned frequency a bit\nand found that suppression is OK at 165 MHz and above, and gets worse\nas the frequency goes down. On 136 MHz (on which I don't transmit\nexcept on a dummyload of course), I found that harmonic suppression\nwas *negative* in some cases. Some of the publications confirm this,\nso my measurements are sound and it's not an incidental case.\n\nOn request of the owner, I did the \"capacitor mod\" (adding a capacitor\nto the lowpass filter) and found that the suppression was still inacceptable.\n\nI purchased an UV-3R mark 2 (dual frequency on display) and established\nthat while it was \"mark 2\", the harmonic suppression was as poor as\na Mark 1 radio. I have not voided the warranty yet on this radio \nto do the capacitor mod on the Mark2 radio, but I'm not hopeful.\n\nWhile some people claim that \"it may pass the specs because the Mk1 radio\ncomes with separate antennas for VHF and UHF\", the mark2 comes with \na dualband antenna and for sat work, with an Arrow antenna or similar, \nharmonic attenuation of the antenna is nonexistant - we sat hams use \ngood antennas!\n\nMail sent to the manufacturer address in the manual on this issue \nremains unanswered.\n\nThe Dutch regs specify '-36 dBm or -60 dBc, whichever is highest'\nand this radio doesn't even come close. FCC regs may be less tight,\nbut I think our transmissions should be to the highest standards\nand frankly, this radio doesn't come close.\n\nMy conclusion so far is that the thing may be good enough for listening,\nbut when you want to transmit then this radio is only useful if your\ntable tips and you need something to remedy that, but not for\nmaking QSO's.\n\nI have not measured the UV-X4 but have been told the internals are\nthe same - the controls are in the same position, in any case.\n\n73,\n\nGeert Jan PE1HZG\n\nPS: the separate charger does not have any protection circuitry\nin it and depends on the protection circuitry in the battary itself\nto charge (and protect) a dangerous LiIon cell. \nPersonally I would not use this unless I have it in sight and\na way to remove power quickly - these cells are temperamentful \nwhen overcharged, and the battary protection circuit is not intended \nto replace a correctly designed charger protection circuit..\n\n",
    "attachments": []
}