UrBackup VS Mumble

UrBackup https://www.urbackup.org/ is the one that I use for years

If anyone came here looking for good quality, open source and free backup software I recommend UrBackup and Kopia.

Free, open source, maintained regularly: www.urbackup.org

I'm looking at https://www.urbackup.org/

You could have a look at UrBackup. Its a client/server backup solution. Also you could rsync the local backup server too the remote lokation.

I would also recommend UrBackup. In my experience it's extremely reliable. https://github.com/uroni/urbackup_backend

Veeam gets most of the hype these days, but if you don't need a Mac client, UrBackup is a solid option. Full & incremental file and image backups for one machine or your whole network, scheduling, rolling copies, etc.

Kopia does not 'image' your whole machine.

A real shame imaging is the time saving component if a system is not recoverable. People want to get their systems up and running as fast as possible.

A combination of imaging and file back up is the best way to do that. For now I'll stick with http://www.urbackup.org/

I think Sonobus is overkill. I suggest you look at a couple of relatively old-school gamer voice chat tools - Mumble or Teamspeak. Mumble is open-source and the connection is always encrypted, Teamspeak is commercial but the free tier should be fine for you - but you have to make sure to manually turn encryption on yourself. It has been a long time since I used either, so I don't know which is easier. Both of them require you to run their matching server software.

Mumble's latency is unbeatable imo, it's basically their main focus and shows.

The sticking point for me is the lack of persistent messages, something the devs strangely think is a privacy plus. Issue open since 2016: https://github.com/mumble-voip/mumble/issues/2560

If you drop out for a minute you won't have access to anything that was posted in chat, which makes it useless for anything other than voice only comms, that might suit some business purposes but I've always needed to post links or screenshots in chat during meetings.

There's any number of alternative chat applications available, like Element, Mumble, Teamspeak etc.

Mumble?

I think Mumble might fit what you're looking for. It's been a very long time since I've used it, but it seems to still exist: https://www.mumble.info/ - I've used previously for exactly what you're describing, events with lots of crew dispersed around and no budget for radios. I had it installed on an AP running OpenWRT so it was just a case of plugging that in and getting people to install the app and connect to it.

Along with the options already mentioned, if you're not into TeamSpeak, there is an open source alternative called Mumble which operates in the same manner. No internet required, and is supported on multiple platforms.