[amsat-bb] Re: Arrow antenna reconfiguration results - UPDATE

[Charles Suprin]

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 <wb3jfs at cox.net> 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" <nss at mwt.net>
> To: "Gary "Joe" Mayfield" <gary_mayfield at hotmail.com>
> Cc: "'AMSAT-BB'" <amsat-bb at amsat.org>
> 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 AMSAT-BB at amsat.org. 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 AMSAT-BB at amsat.org. 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 AMSAT-BB at amsat.org. 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 AMSAT-BB at amsat.org. 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 AMSAT-BB at amsat.org. 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
>