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RE: Ok! APRS on ISS again?



Hi Bill,

Glad to hear you are making progress.  It sounds like you have everything
set up properly.  Here are some thoughts:

The reason you may not be getting in is the "unheard" collisions that are
occuring.  Be aware that ISS is "hearing" at lot more stations than you are
so the potential for collisions is very high and you won't "hear" the
collision like you would when monitoring the terrestrial APRS frequency.  If
a collision occurs, nothing is going to get digipeated.  In my opinion, that
is probably the leading cause to not getting a digipeat on a good pass.

I am using a copper pipe J Pole antenna tuned for 145.99 (1:1 SWR), 50W at
the transmitter, and low loss coax.  This is by no means an ideal space
communications setup, but it receives fine and is fairly effective at
getting into ISS.   I probably have a 30 - 50% success rate at getting a
digipeat which I think is reasonable considering the setup.

Just to help you eliminate one of your variables, I use RS0ISS-3 as my path
and it works fine.  That is a zero, not an "oh". I'm sure you know that, but
just to be absolutely sure.  Usually it's the simple mistakes that get me!

Also, 145.99 is definitely the right uplink frequency so you can check that
off your list.  I do not adjust for doppler and it works fine.

I hope this helps!  Keep trying!  Just remember, if it worked from the start
it wouldn't be any fun and you wouldn't learn anything.  That's what I keep
telling myself. ;-)

73!

A.J. Farmer, AJ3U
http://www.aj3u.com



-----Original Message-----
From: owner-AMSAT-BB@AMSAT.Org [mailto:owner-AMSAT-BB@AMSAT.Org] On Behalf
Of Bill Bruno
Sent: Wednesday, July 21, 2004 6:51 PM
To: amsat-bb@AMSAT.Org
Subject: [amsat-bb] Ok! APRS on ISS again?


With all the help I've received from everyone, I now have my radio and
computer working , and copying aprs from the ISS. Any orbit over 10 degrees
I copy stations. That's the good news!
Bad news! I cant seem to get my signal into the space station. I'm running
APRS exactly the same when tuned to ISS as I do on the regular aprs
frequency. With the exception of the TNC settings in "Unproto APRSM via"
box. I've tried RS0ISS-3,  RS0ISS-3,sgate,wide. I've tried sending my
position, sending messages to "all", sending messages to specific stations.
Nothing apparently gets there. The radio is transmitting on 145.990 each
time I send. I'm probably getting about 60w at the antenna which should be
way more than enough.  My keps and antenna must be good else I wouldn't be
copying so many packets and stations. My feeling is that I've got something
set wrong in APRS. Probably something simple that I'm missing
My ground aprs runs through a d700,  ISS through a TS2K. The TNC Type in TNC
settings is "Single Port"  No other commands in settings besides the unproto
path.
Any suggestions?? Bill
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