For the past month I've been playing around with and learning a new-to-me HF chat application called VarAC (or Vara Chat). I first heard about VarAC earlier this year, but was wrapped up in other radio things and didn't pay it any attention. Then several weeks weeks ago I caught a discussion thread on the Vara Groups.io site focusing on VarAC, and I became interested enough to give it a try.
What is VarAC? VarAC is an HF chat application developed by Irad Deutsch, 4Z1AC. VarAC uses Vara as the communications protocol, so it 'sits' on top of Vara and takes full advantage of Vara's robust connection reliability and speed capabilities. VarAC competes in the same ham radio application space as JS8CALL, an application I've written about in the past. When JS8CALL came out about 3 years ago I was impressed. Finally, an HF digital chat mode that was robust, professionally developed and offered excellent functionality. Plus for the huge existing base of FT8 (WSJTX) fans, learning the new application was a cake-walk since it's the JS8 protocol is based on FT8. I pushed hard (with only limited success) to have JS8CALL adopted as a communications standard within our local and state ARES organizations.
And then along comes VarAC. VarAC and JS8CALL share a lot of functionality. They're designed to do the same thing - live keyboard-to-keyboard chat on HF - so you'd expect that they share many of the same features. The differences in functionality are a reflection of the transport protocols (JS8CALL vs. Vara) and each developer's vision for their own product. Both applications are equally good in within their own design and implementation envelopes.
|The W8BYH Venn diagram of JS8CALL & VarAC features|
VarAC includes a few neat features that JS8CALL lacks. Perhaps the biggest one is the ability to transfer files and images, something JS8CALL can't do (...yet?). VarAC's transport mode is also interesting. It's a very tight P2P connection, established and maintained by Vara. It's as though Vara sets up a VPN-like tunnel between the communicating stations, and makes sure all message traffic is heard on both ends 100% error free. To do this, VarAC selects a frequency 'slot' or channel for each P2P session, and holds that slot until communications are complete and either party formally ends the session. VarAC is also very good at attempting to re-establish connections if something inadvertently happens to break the connection, like band conditions changing drastically in the middle of a QSO.
Is VarAC a better EMCOMM tool than JS8CALL? I can't say. JS8CALL does offer a few features that make it a compelling choice - the ability to do group calls and the ability to use third party JS8CLL stations to store and forward message traffic. But the VarAC developers have just announced that the upcoming release (within a few weeks of this post) will include the first version of 'store and forward' capability.
I'll be doing a more in-depth comparison of JS8CALL and VarAC in the future. But for right now your homework assignment is to go out and install and configure VarAC and make some contacts!