[aprssig] PCSAT2 FM Repeater Experiment results
bruninga at usna.edu
Thu Sep 29 12:48:41 CDT 2005
>>> "Luc Leblanc VE2DWE" 09/29/05
>On the 1026 pass...i was able to hear Eric during
>the whole pass and i realized that i was transmitting
>at 9600BD!! when he [said] he was not listening
>at 9k6 i guess he was referring to me...:(
Thanks Luc and everyone else that played with us this
morning. As you can imagine Murphy was visiting both
classes. On the first pass, a single error led to
us spending the entire pass trying to figure out
why the Transponder was not being commanded on.
(even though it was on) So therefore we were not
simultaneoulsy watching the packet downlink for users.
On the second pass, things worked, and we saw
these calls: WA1KAT, K1ICO, AJ3U, W8AAS...
(plus Luc at 9600) and one other call. A student
walked off with the log so I'm not sure right now.
>Even with ARISS packet OFF i was hearing packet
>burst at 437.975
Yes, our FM donwlink shares the transmitter with
our side B command system so those were command
and telemetry packets.
The scenario here was that we had two classes
of about 16 students each who had never seen
PCSAT2 before. I got to give them a 30 minute
power point description and then I got 8 volunteers
to man these stations:
1) Command station (actually that was me)
2) Telemetry receiver & display
3) Instant-Track and antenna controlller
4) Instant-track and voice antenna controller
5) Voice operator, also looking at packet screen
6) Voice receiver operator tracking doppler on 437.975
7) Internet montitor watching the FINDU web pages
8) APRS display monitor
We got them to the ground station with 5 minutes to
get familiar with their station. ANd then the pass
began. Of course lots of prior planning could do
this better, but we dont have that luxury at an
academy where every hour of the day they are
assigned other things. So we have to do the entire
PCSAT2 lecture and demo in one single class room
THe pass 1 problem turned out to simply be the
volume on the Voice monitor downlink receiver
(a TS-2000 with 65 front panel controls) was
on zero. (My fault because I left it that way after
last nights test). I had only trained that student
to tune Doppler, never mentioned volume.
Now, because I was not hearing audio on the downlink,
I paniced and assumed it was the command link, and
so wasted the rest of the pass trying to re-connect
to both the A and B sides and try the varous alternate
command capabilities. (Apparently it was working
all along. But since we had no feedback, the voice
operator basically said nothing.
On the second pass, it worked fine. But this was a
completely new class and they had even less time
to prepare. I was disappointed at the audio level.
It sounded great when I tried it earlier, but seemd
very low modulation. Maybe the student was not
speaking well into the mic, though it did look like he
was holding it correctly.
I played back the audio files that AJ3U recorded
and there was hardly anything to hear. By the
way, we were only using an omni for our uplink
so that explains our less than full quieting signal.
But we did hear more than what his recording
captured. And another station said he heard it
great through the whole pass.
>Better luck next time
Yes, always lessons learned. And it is so easy to
do when one is all alone in the shack. It is so
hard to do while trying to get 16 people involved.
Oh, the other lesson is to REBOOT all PC's prior
to the event. The packet display laptop for the
voice operator position was looking just great.
But dead as a post.
USNA Satellite Lab
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