[This is the workable successor to G4HYG's PSK63/MFSK16-based "APRS Messenger" for weak-signal HF APRS!]
*The world's first Tri-Mode APRS igates are now "open for business" 24/7 on both 30 and 60 meters....
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The WA8LMF UI-Webservers now receive and igate APRS over classic 300-baud AX.25HF packet,? APRS over MFSK16 & PSK31,? and *now APRS over VARA* on both 30 meters and 60 meters from my home station located in central Michigan.
VARA is one of the newest sound-card "digi-modes".? Written by Jose Ros EA5HVK, It can receive and decode error-free data transmissions at signal levels and S/Ns that literally can not be heard in the radio speaker.?? With stronger signals, it can exceed the net data rate of VHF/FM 1200-baud packet in a 500 Hz CW bandwidth on HF !? VARA is adaptive, adjusting it's transmit speed up and down based on error rate and S/N., switching from simple to more complex multi-tone QPSK wave forms, based on error rate and the bandwidth of the radio.
In a 2300 Hz SSB bandwidth, it can exceed the throughput of 9600-baud VHF/UHF packet on HF!? It is already starting to replace the pricey (USD $600) SCS Pactor4 modems on Winlink HF radio email systems, purely in software with a standard soundcard interface.? The basic version, usable on the low data rates of APRS, is free.? A USD $70 registration unlocks the higher-speed modes.
Currently, the other widely-used activity, layered on top of the VARA "softmodem" is "VarAC Chat",? a live keyboard-to-keyboard chat application that can also do file transfers and "igate" received beacons to the PSK Reporter network. Running on top of VARA, it can equal the weak-signal performance of FT-8, but with free-form conversations instead of the? hello--sig report--goodbye canned exchanges of FT-8.
VARA presents a KISS-over-IP interface to external programs. In principle, any application that can run over classic packet TNCs (messaging systems, BBS systems, APRS, etc) can run over a VARA link instead,? with an ENORMOUS increase (15-20 dB advantage) in weak-signal capabilities.? I have been testing APRS-over-VARA for over a year now. Some of my findings early this year are summarized on my web site at:
<> This was a competitive "shoot out" between classic 300-baud HF packet and VARA on 60 meters, on a 500-mile road trip.
At least three APRS client applications (PinPoint, APRSis-32 and YAAC) can link directly to a KISS-over-IP interface.? For older APRS clients, like *UIview*, that can only do KISS over a serial port, the third-party "Swiss-Army-Knife" of com port utilities "VSPE" can quickly and easily create an? IP<-->Serial-Com-Port? bridge. Full details on setting up VARA for use with APRS applications is here on my web site:
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Stephen H. Smith wa8lmf (at) aol.com
Skype:??????? WA8LMF
EchoLink:? Node #? 14400? [Think bottom of the 2-meter band]
Home Page:
"Studio B" Ham Shack on Wheels
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-- APRS over VARA? --
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60-Meter APRS!?? HF NVIS APRS Igate Now Operating
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Flying Digipeater!
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