[amsat-bb] ARISS packet

JoAnne Maenpaa k9jkm at comcast.net
Tue Feb 28 16:48:16 UTC 2017

Hi Rick,

I'll see if I can offer any additional tips. I'm sure if you have questions
other guys will have some also.

> ... set up UISS with SoundModem to work with my Flex5000A.

There are some changes in UISS settings to work with Soundmodem (Figure 10
in the article) which you likely have made. I start Soundmodem first
followed by starting UISS. When UISS starts it shows a message that it
connected with Soundmodem:

   Connected to Server
   Port1 with SoundCard Ch: A;

On the UISS main screen I set these pulldowns (you can manually type in the
values if they aren't in the pulldown menu):
To as CQ 
Via as ARISS
TX Text/Data as =4211.29N/08827.08W-Greetings (my lat/long, the "-" is the
code for the house symbol on the map, and Greetings is whichever text you
want to use for CQing. When I click the Text/Data F5 button it transmits.

On the Soundmodem settings I've selected AFSK AX.25 1200bd and I left that
little window set at 1700 which seems to be a default.

One note about the soundcard packet applications is they will only display
packets that are 100% correct with no checksum errors. I miss the feature on
hardware packet where you could PASSALL to the screen including the
incomplete packets. Some packets sound "good" but if it contains a checksum
error the software won't display the message.

I don't know if the Flex 5000 needs any additional interface settings. I've
observed what Alan mentioned that Soundmodem on receive is pretty tolerant
of levels. I'm seeing different sound levels on receive here between
different computers. I know my FT-857D is sensitive to transmit sound levels
and I need to use the Windows audio mixer slider to keep the FM deviation
within limits.

On another computer running an SDRPlay for receive I've observed that
VBcable always seems to run with higher levels but Soundmodem decodes OK.

> ... clues how to set up UISS for terrestrial APRS packet on 
> 144.390 to enable me to test this setup by getting some feedback 
> that shows things are working?

When I listen on 144.390 for testing all I see is the raw APRS data. I don't
transmit on 144.390 since I'm not active on APRS (cool maps though). The raw
APRS packets look like:

1:Fm W9RCG-2 To APU25N Via K9ESV-10*,WIDE2* <UI C Pid=F0 Len=61> [09:43:58R]
=4307.10N/08807.20W#APRS&DIGI @ Menomonee Falls, WI {UIV32N}

I find it useful to see some test signals on 144.390. In the mishmash of
callsigns and routes you can tell who transmitted the packet by the
asterisk. The only path information you need for ISS packet is the UNPROTO
set to CQ VIA ARISS. I found that the settings to decode terrestrial packet
transfer directly to receiving packets from the ISS and PSAT even though the
content details differ between terrestrial and space.

The map on http://www.ariss.net/ only shows that stations that were received
by a satgate station. Sometimes half of my packets aren't gated via satgate
to the internet even though I received my own (and others) packets directly
at my station. This web page will still show you if you were satgat'ed
without you sending APRS information. You'll see your transmitted text
without position information. If you transmitted position information that
would be displayed on the map portion of the web page. (That map is zoomable
so you can get close-ups on your area.)

I guess it goes without saying, but I'll say it anyways, tracking the
Doppler shift on 437.550 is important on both the transmit and receive legs.
Packet on 145.825 will be easier once they get the chance to install the new
Ericsson radio.

73 de JoAnne K9JKM
k9jkm at amsat.org

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