[aprssig] AFSK vs PSK

[Bill Vodall]

> I often sit here listening to AX25 on AFSK and note the number of missed packets

Try the Dire Wolf soundcard modem/APRS software for a comparison.
It's using some advanced techniques and might do better.

Compare your existing system decode rate with the WA8LMF test CD and
see how many packets it decodes.  The Dire Wolf system reportedly
captured 976.

>From the download page:  http://home.comcast.net/~wb2osz/site/?/page/Download/

"Version 0.9 - November 2013
New features:  Selection of non-default audio device for Linux ALSA.
Simplified audio device set up for Raspberry Pi.  GPIO lines can be
used for PTT on suitable Linux systems.  Improved 1200 baud decoder:
976 packets decoded from WA8LMF TNC test CD.  Multiple decoders per
channel to tolerate HF SSB signals off frequency.  Command line option
"-t 0" to disable text colors.  APRStt macros which allow short
numeric only touch tone sequences to be processed as much longer
predefined sequences."

>From an APRSSIG post by Scott a few years ago:

"For the Tracker2, I've been getting around 910.  967 for the KPC-3
(non-plus), 970 for the uTNT, and 991 for the Tracker2 with a TCM3105
(tapped from a KPC-3).  With the new active input filter the T2 should be up
in the 950's or so, ...."





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> I think it is due to the SN ratio.
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> Would something like PSK be a better option ?
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> - Andrew -
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