> The mostly unpredictable and extremely low duty cycle modes of non-line of sight VHF/UHF propagation like tropospheric ducting are not a realistic option for communications networks. Alternately the more reliable tropospheric scatter is a brute force solution requiring high output power of a kilowatt or more with big horn antennas.

A friend and myself are currently prototyping a solution where we transmit data using the near vertical incidence skywave (NVIS). Possibly the only option, when you want to avoid infrastructure at all costs. Of course you have the disadvantage of huge HF-antennas. To make this setup usable at all, we are trying with 20m long copper cables close to the ground. If this does not work we will try magnetic loop antennas.