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RE: K4HTA satellite experience.



Very nice experience! Ed  N8EQJ

-----Original Message-----
From: owner-AMSAT-BB@amsat.org [mailto:owner-AMSAT-BB@amsat.org] On
Behalf Of Iain McFadyen
Sent: Thursday, June 30, 2005 11:46 PM
To: amsat-bb@amsat.org
Subject: [amsat-bb] K4HTA satellite experience.

K4HTA is the Vienna Wireless Society (Vienna, Virginia, USA).
 Some 8 weeks ago, during the 'show and tell' portion of our local club
meeting, I stood up and announced that a new satellite had been launched
from India (VO-52). Someone at the back of the room shouted "...Looks
like
we've found our Satellite station captain for Field Day!!"
 Protesting loudly didn't change the situation: But a whole slew of
volunteers approached me and loaned me an FT-847, Arrow,
Yaesu5500/GS232,
and various other components of a satellite station. I enjoy a
challenge...
 In the last few weeks, I have had eight satellite contacts on VO-52 and
FO-29, with a couple of attempts on AO-51 (V/U) and SO-50. These
contacts
were made from the balcony of my 12th floor condo in McLean, VA. I have
a
clear semi-circular outlook centred on NNW.
 So it was with some trepidation, that I packed up all the kit into the
truck and disappeared off in the direction of the Field Day site. We
substituted a 5ele+5-ele cross-Yagi on 145 with a RHCP phasing harness,
and
an 11-turn helix on 435 for Field Day. (These wouldn't fit on the
balcony!!).
 We completed the station setup almost on time, but just missed the
first
satellite pass of Field Day (VO-52 at 1800UTC, on a 3degree elevation
pass
to the West).
 I had already pre-selected VO-52, FO-29, SO-50, AO-7, AO-27, and ISS in
the
Satscape screen, and told Satscape to automatically track satellites in
range. There were some long periods of inactivity in the schedule for
our
location, so I went in to Satscape and added all the Iridium satellites
to
the selected satellites. The Az/El rotor proceeded to track the Iridium
satellites across the sky, starting at AOS and successfully following
the
predicted paths to LOS. Great!
 So, just before FO-29 appeared for its first visible pass at our
location,
I de-selected all the Iridium satellites and waited for the rotor to
start
following FO-29.
 Hmmm.... nothing heard at AOS. A quick look out of the window of the
van
(the operating position was in a converted Ford Van), and I was shocked
to
see that though the Satscape program was predicting the satellite to be
at
051 degrees azimuth and 4 degrees elevation, but the rotor and antennas
were
pointing at 051 degrees and 45degrees!!!
 Quickly put the system in manual, forced the elevation down to 4
degrees,
and completed our Club's first Field Day satellite contact in almost a
decade (last sat contact was using HF!)
 I re-enabled the Iridium satellites in the selection list and the rotor
continued to behave itself perfectly. I disabled Iridium and waited for
the
next useable Amateur satellite pass: Can't remember but I think it was
SO-50. It tracked SO-50 successfully though no successful contact.
 Here comes FO-29 again: Oh no! The Az/El mount is again pointing at a
ridiculously high elevation compared to the predicted pointing
information.
I rebooted everything: The PCs, Satscape, the GS232, the 5500
controller,
and waited for the next pass. Success! Now the array was successfully
tracking correctly!
 FO-29 proved to be difficult to get any more contacts. So I switched
over
to VO-52, and made the second Field Day contact on VO-52. Oh so easy!
The
UHF-up/VHF-down frequency relationship makes things so much easier: The
VHF-up/UHF-down configuration causes us problems with spurious (3rd
harmonic
or thereabouts) from the VHF transmitter.
 Every time the ISS flew within range a whole group of listened on
*every*
ISS pass to see if there was any voice activity. All passes observed
here
were packet only on 145.800. I'm puzzled by those people reporting
successful FIeld Day voice contacts. Was there voice activity on a
different
frequency?
 Strange co-incidence, but all our Field Day contacts by satellite were
with
stations in MN! Thanks to all those who helped us complete this
challenging
task!
 Iain KI4HLV Satellite station Captain: K4HTA. FM18jw Fairfax County,
Virginia, USA.
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