What is the best way to transmit data over a radio channel over long distances?

Question

Iron

Hello.
I had a need to transfer data over a distance of about 6 km. The data itself is gps coordinates. There is no direct line of sight. Please, does anyone know how to do this correctly?
Aircraft models on radio control are controlled at a sufficiently large distance. Maybe these transmitters can somehow be hooked up to a rasberry and taught to transmit data, or maybe there is a ready-made solution, and I'm reinventing the wheel.

Answer 1

Aircraft models are controlled in the 40 MHz and 2.4 GHz bands, but there is a line of sight there. Not far beyond the horizon finishes 27 MHz, even further - shortwave equipment. True, this requires full-size stationary antennas. And judging by the fact that you were going to transmit the coordinates, you have some kind of transport.
So there are three options:
1) mobile communication
2) satellite
3) repeater