[amsat-bb] Re: Some Elmering requested for uplinking to ARISSAT-1

Burns Fisher burns at fisher.cc
Thu Nov 3 16:03:53 PDT 2011

Thanks Dave and everyone else who responded, both personally and on the
board.  To comment on a couple of comments: I certainly expect to hook up
computer control of the doppler comp etc, but was trying to do it manually
at first just to understand better.  Re my problems inside:  The shingles
on the house are pretty new so are not embedded with guck.  However, I
expected them to be pretty neutral.  Not so.  But anyway, I've given up
having antennas in my attic, and I'm outside now exclusively.  Re power,
using CW to match up.  Ok, I'll try my full power out, and CW.  Thanks for
the ideas.  Re other sats, beam, etc:  Good ideas for sure; I wanted to
eliminate variables, and since I can't mess up pointing with an omni, and I
have received ARRISat easily, I figured ARRISat involved the fewest
variables.  But I'll try the other stuff too.

Thanks again to everyone!  I'll let you know how I make out.  In the
meantime, I'd like to hear from anyone who has been successful with an omni
or Lindenblad with 50W uplink.

Burns, W2BFJ

On Wed, Nov 2, 2011 at 6:49 PM, David Palmer KB5WIA <kb5wia at amsat.org>wrote:

> Hi Burns,
> My 2 cents -- sounds like things are mostly okay (your recieving setup
> is obviously good if you can hear others in the transponder passband).
>  The big factor that I can see is lack of gain on the uplink.  I've
> successfully gotten into ARISSAT with my 5W QRP radio, but that's
> using a 13 dBd gain yagi.  In theory the ERP of your 25W uplink isn't
> too far below that, so it would be worthwhile trying the 50W to see if
> that helps.  That or switch to an antenna outside with some gain...
> Other factors to consider are sometimes the sats transponder is off
> (so even if everything at your end is okay you won't hear your own
> signal, nor anyone elses).  And the return signal varies greatly from
> pass to pass, depending (I think) on the relative orientation of the
> antenna stub.
> Also be sure to try finding yourself on CW first .... SSB is often
> very difficult to copy on ARISSAT, much easier to start with CW and
> once you've found yourself switch over.
> 73! de Dave KB5WIA
> > Can someone comment on my method, both in terms of technical goodness and
> > good operating practice?  A couple specific questions:  1) Xmitting in
> the
> > middle of the passband and just scanning, I should be able to at least
> > briefly find myself without messing with doppler, right?  I was planning
> to
> > lock the receive and transmit frequencies (constant sum) once I found
> > myself and follow the doppler by hand, but I never got to that step.  2)
> > I'm right that the sidebands are inverted from receive to xmit, right?  I
> > think I would hear something even if that was wrong.  3) Finally, what
> > about power?  How much have you required for success on ARRISAT?   I was
> > running around 25W.  I could boost up to as high as 50, but I can only
> > diddle so many knobs in 5 or 10 minutes :-)  3) I know a beam would be
> > better, but trying to reduce variables, and pointing is one of them.
> > Besides, I'm inside in my shack!  But has anyone successfully uplinked
> with
> > an omni/circular?  I can always remove the parasitic elements and end up
> > with a center-fed dipole to remove the circularity.  (Not sure how that
> > would affect the impedance match...)
> >
> > Thanks!
> >
> > Burns, W2BFJ

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