[amsat-bb] Re: Improving performance of packet communications through the ISS

JoAnne Maenpaa k9jkm at comcast.net
Wed Jun 12 07:30:41 PDT 2013

Hi Les,

Here is a quick follow up to your earlier question:
> ... SignaLink interface, through Packet Engine Pro and UISS ...
> ... provide other suggestions on how to improve my ability to 
> communicate through the ISS?

Replies from others to your question offered alternatives to using
AGWPE and UISS for software packet application on the ISS digipeater.
These included substituting either 'Dire Wolf' or the UZ7HO AX.25
modem in place of AGWPE.

Yesterday I had a chance to try substituting 'Dire Wolf' for AGWPE.
Here is a quick summary of my set up and results.

1. Download Dire Wolf from http://home.comcast.net/~wb2osz/site/ 

2. The setup guide and user guide are easy to follow.

3. The out-of-the-box application for Dire Wolf is for APRS. I tuned 
   to 144.390 for a quick test and immediately received raw and
   APRS data just like the user guide says.

4. Next I tested with UISS. 
   a. Start Dire Wolf first.
   b. You need to change the setup of UISS between running with 
      AGWPE or Dire Wolf. 
   c. In UISS top menu select Setup -> UISS -> LAN
   d. In LAN setup click on 'Enable LAN Mode' Host Port 8000
   e. UISS may ask you to restart, go ahead and restart UISS.

The Dire Wolf is only a software emulation of a hardware TNC. You
still need a user interface for you to communicate via packet. That is
what UISS or UI-View will do for you. There is no place to enter the
PASSALL command but the error correction in Dire Wolf visibly improved
performance. I saw more packets than previously with AGWPE (AGWPE just
rejects the whole message if there a checksum error).

One glitch for me is Dire Wolf displays an error message when I
transmit from UISS. It says something about a packet header error. But
it transmits my UI packet OK. I saw myself successfully digipeat
several times via 145.825 ARISS packet on last evening's passes.

I think the error message is related to how UISS talks with Dire Wolf.
I noted seamless integration with Dire Wolf and APRS applications such
as UI-View. I haven't had time to dig much further at this point. When
time permits I'll try the UZ7HO software with UISS but I gotta get
back to the July/August AMSAT Journal project.

Links to dozens of ham radio digital mode software packages, including
Dire Wolf and UZ7HO, can be found at this starting point:

73 de JoAnne K9JKM
k9jkm at amsat.org 

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