Could very well be. 73,
Jeff WB3JFS ----- Original Message ----- From: "Gary "Joe" Mayfield" <[email protected]> To: "'Jeff Yanko'" <[email protected]>; "'Charles Suprin'" <[email protected]> Cc: "'Joe'" <[email protected]>; "'AMSAT-BB'" <[email protected]> Sent: Friday, October 02, 2009 6:27 PM Subject: RE: [amsat-bb] Re: Arrow antenna reconfiguration results - UPDATE > We are missing the easy answer. He had diplexer that was off spec. It > happens. > > 73, > Joe kk0sd > > -----Original Message----- > From: [email protected] [mailto:[email protected]] On > Behalf Of Jeff Yanko > Sent: Thursday, October 01, 2009 4:28 PM > To: Charles Suprin > Cc: Joe; AMSAT-BB; Gary "Joe" Mayfield > Subject: [amsat-bb] Re: Arrow antenna reconfiguration results - UPDATE > > Hi Charles and the group, > > FB on the numbers. Interesting to say the least and thanks for taking the > time to look further into this topic. > > Questions? I have a few after looking at these numbers and performing > more > observations. > > First, are you testing just the diplexer and not the diplexer and the > antenna combined? This could result in an overall number and not just the > diplexer alone. How could there be a large discrepency between > preliminary > reports, 2.65dB and .5dB now. Could be equipment calibration, human > error, > etc. from previously tested, or attempted testing of the device. I don't > believe any improvements have been made to the Arrow diplexer, but who > knows? > > Second, I switched back to the Arrow diplexer and made another comparison > with the Comet diplexer. Again, no comparison, the Comet outperformed. > Why > would this happen if the two are pretty close to one another in numbers. > The Comet has .25db loss at VHF and .26 at UHF. > > Third, with the Arrow diplexer I wouldn't begin to receive the birds until > almost 3 minutes after AOS, with the Comet diplexer a minute to 1.5 > minutes > after AOS. Yes, watch calibrated to WWV and multiple times of acquiring > the > birds. I've tried both setups with the HT and D710 and they both show the > same results respectively, Arrow diplexer vs. Comet diplexer. The antenna > and coax remain the same, the difference, the diplexer. May not be test > lab > quality but something is proving itself. What is it? > > Finally, is it just my Arrow diplexer? Doesn't appear to be shorted or > any > defects to it. Actually looks great and assembled very well. I've > encountered others saying the same thing. However, a very noticable > difference to the overall performance. > > > 73, > > Jeff WB3JFS > > > ----- Original Message ----- > From: Charles Suprin > To: Jeff Yanko > Cc: Joe ; Gary "Joe" Mayfield ; AMSAT-BB > Sent: Thursday, October 01, 2009 1:09 PM > Subject: Re: [amsat-bb] Re: Arrow antenna reconfiguration results - > UPDATE > > > Howdy Jeff, > > Someone asked and here we go. A file attachment follows. > > Actually the diplexer looks pretty good. Less than half a db of loss at > VHF and around half a dB at UHF. I checked the calibration and that was > within tenth of a dB over the entire range. > > Any questions. > > Charles > AA1VS > > > On Sat, Sep 26, 2009 at 6:26 AM, Jeff Yanko <[email protected]> wrote: > > Hi Joe and all, > > I doubt if the Arrow diplexer has 20dB of loss. If it did, we'd never > receive a signal! :) > > I believe somebody here on the -bb will be performing a test on the > Arrow > diplexer using a vector/network analyzer. It will be interesting to > say > the > least. There were preliminary reports saying the device had a loss > anywhere > from 2.65 to 2.80dB. That's close enough to 3dB which is technically > half > power loss. Add the loss of a short piece of coax and it will > certainly > be > pushed over the 3dB line. > > If I recall correctly, cross polarity is also a 3dB loss. I have > noticed > that when I rotate the antenna I might get a stronger downlink but I > never > lose it when I rotate it back. Before, when I would do that it would > drop > once I rotated in either direction from the peak signal. Basically > what > is > going on is the lossy device is removed and replaced with a more > efficient > one, that extra net gain you just boosted now shows how the system on > the > antenna side of the diplexer is truly performing. > > I don't have an antenna analysis program to perform a test, but what > does a > 7 element 440 yagi pattern look like and what is its overall gain? > > What we need to do is break down the antenna configuration into 3 > segments, > see what their losses and gains are then combine them for the overall > figure. The 3 segment would be the antenna, the diplexer and the coax. > Each one will be tested individually to give an accurate number for > each. > > > > 73, > > > Jeff WB3JFS > ----- Original Message ----- > > From: "Joe" <[email protected]> > To: "Gary "Joe" Mayfield" <[email protected]> > Cc: "'AMSAT-BB'" <[email protected]> > Sent: Friday, September 25, 2009 6:42 PM > Subject: [amsat-bb] Re: Arrow antenna reconfiguration results - UPDATE > > > > > as in the texts below, there is something else going on here. > > > > That Diplexor can not be all that bad. two reasons. > > > > How many db down is the front to side of that antenna? > > > > and I can not imaging someone would sell a diplexor that has greater > > than 20 db of losses. > > > > because of the statement that how criticalpolarity was with the > > original, and now the antenna has to be nearly 90 degrees cross > > polarized to make it drop out uhh > > > > that close to 30 db, > > > > at least 20,, > > > > something else is going on here > > > > Gary "Joe" Mayfield wrote: > > > >>> > >>>Another issue I came across was how wide the beamwidth is of the > Arrow > >>>Antenna between the Arrow diplexer and the new diplexer. I was > wondering > >>> > >>> > >>if > >> > >> > >>>this was going to happen and it did. The reason that this happened > was > >>> > >>> > >>with > >> > >> > >>>the old diplexer, the signal attenuated so much that you had to be > >>>pointed > >>>right smack dab on the bird, a few degrees off and you lost the > signal. > >>>Now, with the new diplexer, you can point the beam in the general > >>> > >>> > >>direction > >> > >> > >>>and still copy the bird. In most cases I had to turn the beam 90 > degrees > >>>before I completely lost the downlink! Twisting the antenna to make > >>>polarization changes makes absolutely no difference now. This also > >>>attributes to the fact that now I'm copying the entire pass without > >>> > >>> > >>dropouts > >> > >> > >>>or fades. Makes sense. What I've regained over the lossy diplexer > makes > >>> > >>> > >>up > >> > >> > >>>for any polarization differences, etc. for a better copiable signal. > >>> > >>>Next weekend I will have to try more passes and get a feel of how > much > >>> > >>> > >>this > >> > >> > >>>system has changed. > >>> > >>> > >>>73, > >>> > >>>Jeff WB3JFS > >>>Las Vegas, NV > >>>DM26 > >>> > >>> > >>> > >>> > >>> > >>> > >>>_______________________________________________ > >>>Sent via [email protected]. Opinions expressed are those of the > author. > >>>Not an AMSAT-NA member? Join now to support the amateur satellite > >>>program! > >>>Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb > >>> > >>> > >>> > >> > >>_______________________________________________ > >>Sent via [email protected]. Opinions expressed are those of the > author. > >>Not an AMSAT-NA member? Join now to support the amateur satellite > program! > >>Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb > >> > >> > >>_______________________________________________ > >>Sent via [email protected]. Opinions expressed are those of the > author. > >>Not an AMSAT-NA member? Join now to support the amateur satellite > program! > >>Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb > >> > >> > >> > >>>------------------------------------------------------------------------ > >> > >> > >>No virus found in this incoming message. > >>Checked by AVG - www.avg.com > >>Version: 8.5.416 / Virus Database: 270.13.113/2395 - Release Date: > >>09/25/09 17:52:00 > >> > >> > >> > > _______________________________________________ > > Sent via [email protected]. Opinions expressed are those of the > author. > > Not an AMSAT-NA member? Join now to support the amateur satellite > program! > > Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb > > > > > _______________________________________________ > Sent via [email protected]. Opinions expressed are those of the > author. > Not an AMSAT-NA member? Join now to support the amateur satellite > program! > Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb > > > _______________________________________________ > Sent via [email protected]. Opinions expressed are those of the author. > Not an AMSAT-NA member? Join now to support the amateur satellite program! > Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb > > _______________________________________________ Sent via [email protected]. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
