On 6/12/2024 12:59 PM, Gervais Fillion wrote:
Hello stephen,
Simple question,
What is VARA ?
73 an good ride
Gervais ve2ckn
VARA? is a high-performance soundcard software modem developed in Spain by EA5HVK.? Two versions exist: One for HF over SSB, and one for VHF/FM.
The HF version can nearly equal the performance of the very expensive SCS Pactor 4 high-speed hardware modems, purely in software on a PC with a sound-card interface.? It can exceed the speed of 1200-baud packet in a 500 Hz (CW) bandwidth on HF/SSB. With a full 2.5 Hz SSB bandwidth on HF, it can exceed the throughput of 9600-baud packet.
The VHF version takes advantage of the much greater audio bandwidth of an FM radio. When using a rear-panel wide-audio-response "data port" on a radio, it can exceed the equivalent of 20K baud for data? transfer.
VARA wraps data in two layers of forward error correction, and has incredible weak signal capability similar to FT-8. It can deliver error-free messages or data on HF signals so weak you can literally not hear them in the radio speaker.
VARA is only a modem (e.i a soft TNC). You have to use some sort of application on top of it to do anything.? Most commonly, this is the WinLink radio email client (where it is rapidly replacing the SCS hardware TNCs),?? or the live keyboard-to-keyboard VarAC Chat app.
VarAC has the extreme weak-signal capabilities of FT-8 but allows completely free-form conversations.? When signals are strong with few errors, VarAC and VARA will automatically increase the speed. You can even transfer files error-free to the other user. If that "file" happens to be a picture, you have a noise-free? alternative to SSTV!
Because the VARA modem presents a KISS interface to other software, you can use it as a VASTLY improved replacement for conventional AX.25 packet, for applications like APRS.?? I have been testing and comparing classic packet APRS with APRS-over-VARA for nearly two years now. ? There is simply no comparison -- on HF, APRS position reports over VARA are received successfully nearly TEN TIMES as often as classic 300-baud HF packet.
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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:
APRS-over-VARA igates now operating on 30 & 60 meters
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"Studio B" Ham Shack on Wheels
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-- APRS over VARA? --
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