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GET /hyperkitty/api/list/[email protected]/email/ILVMVTJS62GMKXAMR4B2JQ7ZKIOZEZJH/?format=api
{ "url": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/email/ILVMVTJS62GMKXAMR4B2JQ7ZKIOZEZJH/?format=api", "mailinglist": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/?format=api", "message_id": "[email protected]", "message_id_hash": "ILVMVTJS62GMKXAMR4B2JQ7ZKIOZEZJH", "thread": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/thread/JAHMCBZOJLINBANTZA3RYJQWNO5JU6JJ/?format=api", "sender": { "address": "hamaa1vs (a) gmail.com", "mailman_id": "9f3e2007e5e942b6b7f4b3a380eb09d7", "emails": "https://mailman.amsat.org/hyperkitty/api/sender/9f3e2007e5e942b6b7f4b3a380eb09d7/emails/?format=api" }, "sender_name": "Charles Suprin", "subject": "[amsat-bb] Re: Arrow antenna reconfiguration results - UPDATE", "date": "2009-10-01T20:09:48Z", "parent": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/email/BTOU3A4B5TVEE2QUL4REOEFEHXIAIBGI/?format=api", "children": [ "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/email/MTNRQWTJBUFVUJTRN5HUX4TFFXDCSH7O/?format=api" ], "votes": { "likes": 0, "dislikes": 0, "status": "neutral" }, "content": "Howdy Jeff,\n\nSomeone asked and here we go. A file attachment follows.\n\nActually the diplexer looks pretty good. Less than half a db of loss at VHF\nand around half a dB at UHF. I checked the calibration and that was within\ntenth of a dB over the entire range.\n\nAny questions.\n\nCharles\nAA1VS\n\nOn Sat, Sep 26, 2009 at 6:26 AM, Jeff Yanko <[email protected]> wrote:\n\n> Hi Joe and all,\n>\n> I doubt if the Arrow diplexer has 20dB of loss. If it did, we'd never\n> receive a signal! :)\n>\n> I believe somebody here on the -bb will be performing a test on the Arrow\n> diplexer using a vector/network analyzer. It will be interesting to say\n> the\n> least. There were preliminary reports saying the device had a loss\n> anywhere\n> from 2.65 to 2.80dB. That's close enough to 3dB which is technically half\n> power loss. Add the loss of a short piece of coax and it will certainly be\n> pushed over the 3dB line.\n>\n> If I recall correctly, cross polarity is also a 3dB loss. I have noticed\n> that when I rotate the antenna I might get a stronger downlink but I never\n> lose it when I rotate it back. Before, when I would do that it would drop\n> once I rotated in either direction from the peak signal. Basically what is\n> going on is the lossy device is removed and replaced with a more efficient\n> one, that extra net gain you just boosted now shows how the system on the\n> antenna side of the diplexer is truly performing.\n>\n> I don't have an antenna analysis program to perform a test, but what does a\n> 7 element 440 yagi pattern look like and what is its overall gain?\n>\n> What we need to do is break down the antenna configuration into 3 segments,\n> see what their losses and gains are then combine them for the overall\n> figure. The 3 segment would be the antenna, the diplexer and the coax.\n> Each one will be tested individually to give an accurate number for each.\n>\n>\n> 73,\n>\n>\n> Jeff WB3JFS\n> ----- Original Message -----\n> From: \"Joe\" <[email protected]>\n> To: \"Gary \"Joe\" Mayfield\" <[email protected]>\n> Cc: \"'AMSAT-BB'\" <[email protected]>\n> Sent: Friday, September 25, 2009 6:42 PM\n> Subject: [amsat-bb] Re: Arrow antenna reconfiguration results - UPDATE\n>\n>\n> > as in the texts below, there is something else going on here.\n> >\n> > That Diplexor can not be all that bad. two reasons.\n> >\n> > How many db down is the front to side of that antenna?\n> >\n> > and I can not imaging someone would sell a diplexor that has greater\n> > than 20 db of losses.\n> >\n> > because of the statement that how criticalpolarity was with the\n> > original, and now the antenna has to be nearly 90 degrees cross\n> > polarized to make it drop out uhh\n> >\n> > that close to 30 db,\n> >\n> > at least 20,,\n> >\n> > something else is going on here\n> >\n> > Gary \"Joe\" Mayfield wrote:\n> >\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\n> wondering\n> >>>\n> >>>\n> >>if\n> >>\n> >>\n> >>>this was going to happen and it did. The reason that this happened was\n> >>>\n> >>>\n> >>with\n> >>\n> >>\n> >>>the old diplexer, the signal attenuated so much that you had to be\n> >>>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> >>>\n> >>>\n> >>direction\n> >>\n> >>\n> >>>and still copy the bird. In most cases I had to turn the beam 90\n> 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> >>>\n> >>>\n> >>dropouts\n> >>\n> >>\n> >>>or fades. Makes sense. What I've regained over the lossy diplexer\n> makes\n> >>>\n> >>>\n> >>up\n> >>\n> >>\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> >>>\n> >>>\n> >>this\n> >>\n> >>\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\n> author.\n> >>>Not an AMSAT-NA member? Join now to support the amateur satellite\n> >>>program!\n> >>>Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb\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\n> program!\n> >>Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb\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\n> program!\n> >>Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb\n> >>\n> >>\n> >>\n> >>------------------------------------------------------------------------\n> >>\n> >>\n> >>No virus found in this incoming message.\n> >>Checked by AVG - www.avg.com\n> >>Version: 8.5.416 / Virus Database: 270.13.113/2395 - Release Date:\n> >>09/25/09 17:52:00\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\n> program!\n> > Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb\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", "attachments": [] }