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{
    "url": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/email/CHJFFTQNNYHJ4YOMDXT56MDOM72KAG2H/?format=api",
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    "message_id": "F41260F895414DC5988B128255DDA927@QUECREEK",
    "message_id_hash": "CHJFFTQNNYHJ4YOMDXT56MDOM72KAG2H",
    "thread": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/thread/JAHMCBZOJLINBANTZA3RYJQWNO5JU6JJ/?format=api",
    "sender": {
        "address": "wb3jfs (a) cox.net",
        "mailman_id": "bdfc678d05af4f3f96c14d823fd3fbcf",
        "emails": "https://mailman.amsat.org/hyperkitty/api/sender/bdfc678d05af4f3f96c14d823fd3fbcf/emails/?format=api"
    },
    "sender_name": "Jeff Yanko",
    "subject": "[amsat-bb] Re: Arrow antenna reconfiguration results - UPDATE",
    "date": "2009-09-26T11:48:23Z",
    "parent": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/email/M4H7PMQ5XG3XLBJKSAFLWNAX5F7A5DS5/?format=api",
    "children": [],
    "votes": {
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        "status": "neutral"
    },
    "content": "Hi Bruce and all,\n\nNo problem.  Actually, I wouldn't call it research as much as curiosity. \nMaybe the research will come later when developing something better. :)  I \nknow the antenna \"works\" but can it be made to perform better?  The antenna \nitself is of great quality and workmanship, it's the diplexer that has been \nmaking me wonder if that is the weak spot.  The Achilles heel of the system.\n\nOK on setting up the FT-817 using two coaxes.  I've heard a number of others \ndoing the same thing with great results.  I would suggest doing what best \nsuits the individuals needs and affordability.  You be surprised what one \ncan dream up when you plan it out and follow through with the design.\n\n73,\n\nJeff  WB3JFS\n\n\n\n----- Original Message ----- \nFrom: \"Bruce Robertson\" <[email protected]>\nTo: \"Jeff Yanko\" <[email protected]>\nCc: \"AMSAT-BB\" <[email protected]>\nSent: Friday, September 25, 2009 6:53 AM\nSubject: Re: [amsat-bb] Arrow antenna reconfiguration results - UPDATE\n\n\nJeff --\n\nI really appreciate you doing this research for us. Two additional\nideas come to mind:\n\n1. Those of us with FT-817s could configure its two RF ports to use\ndifferent bands and connect the rig directly to the beam's antenna\nconnectors, bypassing the duplexer. For this purpose, higher-quality\nbnc terminated cable would be useful.\n\n2. If I'm correct, your replacement duplexer is rather larger than the\none it is replacing. It would be a great topic for a Journal article\nif someone with the necessary equipment and expertise were to design a\nreplacement with less loss.\n\n73, Bruce\nVE9QRP\n\nOn Fri, Sep 25, 2009 at 6:10 AM, Jeff Yanko <[email protected]> wrote:\n> Hi all,\n>\n> A quick update to my new project to improving the Arrow antenna, \n> efficiency\n> wise. I wanted to see how well it would perform on gaining and losing\n> access during AOS and LOS. AO-27 is not a good choice since the timer is\n> turned on when it is well above the AOS horizon and it is switched off\n> before it reaches its LOS horizon. That leaves a dependable AO-51 to test\n> it out.\n>\n> With the last setup, the OEM diplexer provided by Arrow Antenna, I would\n> copy AO-51 about 3 minutes after AOS and lose it about 3 to 4 minutes \n> before\n> LOS. Not bad, but people were saying they worked the birds when they were \n> 1\n> degree off of the horizon. I have some pine trees that could be an issue\n> but they are spaced far enough apart that I can work between them and I \n> also\n> have to deal with the McCollough Range to the SSE of me here in Las Vegas,\n> NV. Today, there were 2 passes of AO-51, one at 12 degrees elevation, the\n> other at 74 degrees. During both passes, I began to copy the downlink \n> about\n> a 1.25 minute after AOS. A considerable difference from 3 minutes. The\n> downlink also improved down to about minute before LOS. On the last pass I\n> worked KG6NUB at 0124z and LOS was 0125z and my downlink sounded fairly\n> good, though I was fighting desense. (That's another issue I need to\n> resolve.) Also, on both passes, I never once lost the downlink. No\n> dropouts or fades. I'm still amazed.\n>\n> Another issue I came across was how wide the beamwidth is of the Arrow\n> Antenna between the Arrow diplexer and the new diplexer. I was wondering \n> if\n> this was going to happen and it did. The reason that this happened was \n> with\n> the old diplexer, the signal attenuated so much that you had to be pointed\n> right smack dab on the bird, a few degrees off and you lost the signal.\n> Now, with the new diplexer, you can point the beam in the general \n> direction\n> and still copy the bird. In most cases I had to turn the beam 90 degrees\n> before I completely lost the downlink! Twisting the antenna to make\n> polarization changes makes absolutely no difference now. This also\n> attributes to the fact that now I'm copying the entire pass without \n> dropouts\n> or fades. Makes sense. What I've regained over the lossy diplexer makes up\n> for any polarization differences, etc. for a better copiable signal.\n>\n> Next weekend I will have to try more passes and get a feel of how much \n> this\n> system has changed.\n>\n>\n> 73,\n>\n> Jeff WB3JFS\n> Las Vegas, NV\n> DM26\n>\n>\n>\n>\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\n\n",
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