[Date Prev][Date Next][Thread Prev][Thread Next] - [Date Index][Thread Index][Author Index]

No Subject

Hi folks,

Last night was my first opportunity to test my updated antenna/feed
in with the AO-40 Transponder.  MA 13, at 15 degrees elevation.
With such a low MA, I was hoping for lots of strong signals, and
an easy time getting into the bird myself.  The results were mixed.

The beacon, as expected was very strong, although I didn't hear
anything until the bird was up around 10 degrees elevation.  Trees
and hills in the way, I expect.

As others have discovered, I now have a mild interaction between
the UHF uplink and the S-band downlink.  Transmitting on UHF gives
a rise in the noise level on the downlink.  It's not real severe,
but it was enough to mask my own SSB uplink, as that's never been
very strong.  Since I didn't have this problem before, it must be
due to moving the converter & preamp forward, from behind the dish
to out in front.  The distance from the UHF antenna is smaller now,
and towards the front of the antenna.  Also, the UHF coax passes
right in front of the feed helix...  Probably not the best idea.  My
plan is to first try routing the UHF feed around the back of the dish,
then if that doesn't help, move the whole S-band contraption over to
the 2 meter side of the arm.  If you want to see how it is now, look
at http://www.jps.net/gregd/hamsite.htm

But last night also brought some disappointing results in how the
transponder sounded - very raspy.  My own CW - I can explain with
the above.  But I also heard a few stations call CQ, a very few.
One from JH1, and a couple from North America.  They didn't sound
very clean.  There were also a few spots where there was some sort of
digital/analog mixed wierdness that almost sounded like some of the
digital stuff (non-ham) on HF, with some warbly tones and occasional
CW mixed in.  Does anyone know what I was hearing?  Was there any
other experimentation going on that might have affected the sound
quality on the transponder, or is it just me?

Since the bird was rising in the West on this pass, I am hoping that
the lack of transponder traffic during the short time I was listening
was due to there not being very many stations out over the ocean...
Will try again in a couple of days.


Greg  KO6TH

Get your FREE download of MSN Explorer at http://explorer.msn.com/intl.asp

Via the amsat-bb mailing list at AMSAT.ORG courtesy of AMSAT-NA.
To unsubscribe, send "unsubscribe amsat-bb" to Majordomo@amsat.org