[OZAPRS] Most convoluted HF gateway ever?

Steve stevez at tpg.com.au
Mon Oct 26 19:58:03 EST 2009


Hello all,

As I've got a PSKMail server running on 30M (PSK125, about 700Hz below 
APRS), I thought I'd see if I could decode some HF packets too.
APRS packets are within the audio pass band of my setup (radio tuned for 
10.1475MHz) so why not use the one PC and radio to do two jobs?

Anyway, I don't own any physical TNCs so I had to work out how decode 
APRS packets using the soundcard, on Linux, and without affecting the 
PSKMail server.

This is what I ended up with :-

1) MixW, running under WINE, sharing the soundcard with FLDigi (FLDigi 
is the PSKMail modem). This involved tweaking ALSA config a bit, as 
FLDigi likes to take full control of /dev/dsp. I would have preferred to 
use Linux soundmodem, but I have never seen it decode a 300bd HF packet 
ever. I don't know of any other "native" soundcard modems that do packet 
for Linux.
2) Xastir as the APRS I-Gate. I know there are other ways to do this, 
but Xastir is cool, and I can see a map of the stations I've heard via 
HF as a bonus.
3) Now for the thing that took the longest to work out. A virtual 
"Null-Modem" cable between a Windows app (MixW), running under WINE, and 
a native Linux app (Xastir). It took me a couple of days to work it out, 
but in the end I must say that I love the socat command!

So, it has two systems running (PSKMail and APRS/Xastir), with two 
separate sound card "modems" (FLDigi and MixW), strung together with a 
virtual elastic band (socat).

Does this count as the ugliest HF I-Gate implementation around?
I bet it comes close!

For the record, VK4UN-4 is the first station heard via this monster ;-)



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