Hi guys,
What are some option for reasonably long-range (3+ km) radio communication between uCs on a budget? As far as I can tell, from looking at sources here in New Zealand, the only options as far as off-the-shelf modules go are really expensive or offer only 200m-ish range. Is it possible to create a device (with a uC and a DAC or something?), or to modify existing modules somehow (perhaps directional antennae?) to get sufficient range?