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{
    "url": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/email/WJ56RFR4D4QF2AJXNYFFPYY6ZWAYTFFJ/?format=api",
    "mailinglist": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/?format=api",
    "message_id": "[email protected]",
    "message_id_hash": "WJ56RFR4D4QF2AJXNYFFPYY6ZWAYTFFJ",
    "thread": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/thread/YLYLAYGOHSO7ZVENZE33LYVC6ER2Y26B/?format=api",
    "sender": {
        "address": "ve9qrp (a) gmail.com",
        "mailman_id": "4d6061838db34aba9a1c4722addebfaf",
        "emails": "https://mailman.amsat.org/hyperkitty/api/sender/4d6061838db34aba9a1c4722addebfaf/emails/?format=api"
    },
    "sender_name": "Bruce Robertson",
    "subject": "[amsat-bb] Re: Fw: ELK or ARROW",
    "date": "2008-12-29T03:41:15Z",
    "parent": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/email/YLYLAYGOHSO7ZVENZE33LYVC6ER2Y26B/?format=api",
    "children": [
        "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/email/54RNAGA6MPPBKF5DSHHVSQOGWSSVMOE3/?format=api"
    ],
    "votes": {
        "likes": 0,
        "dislikes": 0,
        "status": "neutral"
    },
    "content": "I had a great time experimenting with homebrew handheld dual-band\nantennas for satellite work before I bought an arrow antenna. It is\nimportant to note that, as in so many applications, higher antenna\ngain is not necessarily better. Think of it as a narrower flashlight\nbeam: are you sure you can point the beam directly at the bird? If you\nlose track of it, how easy will it be to find it again? Moreover, a\nlonger boom means a heavier antenna, and it is amazing how heavy a\nhandheld antenna becomes after 10 minutes!\n\nSo I'd say that it is just important in our discussions of antenna\ngain to discuss pattern. If the handheld satellite antenna's gain is\nimproved by making a pencil-thin front lobe and some side lobes,\nthat's really no good: you'll be too frustrated trying to find the\nbird.\n\nThere are, however, some aspects of the entire receiving system that\nwe can improve. This diplexer number is a bit alarming. I expect it is\npossible to do better.\n\nAnother trick commonly used on home stations is to put a preamp at the\nantenna output. The low-noise preamp improves the overall noise figure\nof the system, and compensates for the 'down-stream' losses if put\nbefore them, i.e., at the antenna.\n\nAs it happens, I've been thinking about how it might be possible to\nsuper-charge an arrow antenna with a 435 preamp. I have a small ARR\nswitching preamp handy, but it needs 12v. Some sort of AA battery pack\nwith a charge-pump circuit might do the trick of small enough. Will\nthe added weight on my wrist be worth the improved reception on 435?\nOnly experimentation will tell.\n\n73, Bruce\nVE9QRP\n\nOn Sun, Dec 28, 2008 at 3:22 PM, Bob K0NR (email list) <[email protected]> wrote:\n> [email protected] wrote:\n>> It seems improving the 2.4 dB of insertion loss of the diplexer would be a\n>> better strategy (although not necessarily easy in the space available) than\n>> attempting to modify what is very mechanically sound antenna.\n>>\n>> 73,\n>> Joe kk0sd\n>>\n>>\n>\n>    I am surprised that the duplexer/diplexer (take your pick) has that\n>    much loss.\n>    Has anyone verified this via a direct measurement (such as via a\n>    network analyzer)?\n>\n>    Bob K0NR\n>\n>\n> _______________________________________________\n> Sent via [email protected]. Opinions expressed are those of the author.\n> Not an AMSAT-NA member? Join now to support the amateur satellite program!\n> Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb\n>\n",
    "attachments": []
}