Meshing two digit number of drones on a military grade reliability is a real uphill battle with chirp based protocols, as the high ToA reaches congestion fast.
> each of them serving as a mesh-network node
might have worked for a bit in the past, but is easily disrupted by jammers, and forced a switch to fiber-optic in-theater. People have learned from that and don't bother with radio anymore, even in new theaters.
Fiber optic tethers limit range and target conditions. You can't go into a forest or even an urban canyon, you basically need to run the drone along roads and fields. And you have to drag it with you, which reduces what you can carry. The fiber itself is very light weight and has a habit of getting sucked up into the props on quadcopters.
There's a lot of frequency hopping and chirp systems being used now, with a mix between analog radios mostly for FPV and digital radios or Starlink for larger ISR drones or larger gliders. Digital still gets used a lot for FPV because of how readily available it is, but good drone FPV pilots want the lower latency of analog and will take it if they can get it.
the flip side of that is that your operator can be miles away, and using repeaters, hundreds of miles away. As the operator is the difficult to replace part, its a fair tradeoff.
Frequency hopping is nice, as is spread spectrum but its still easily detectable, as is the operator.
And giving away their location. Radio is prettymuch dead for drones.
https://trellisware.wpengine.com/waveforms/tsm-waveform/
Nodes can cooperate to beamform and reach greater distances.
Depends on the context, I guess. Distance, jamming probability, availability of relays, etc.
Fiber-optics are close-range.