Red Dirt Signal. The CodeBreakers, #2

Someone is sending a signal. Is anyone listening?Deep in the Flinders Ranges, on a UHF frequency nobody monitors anymore, a coded signal repeats every forty minutes. Patient. Deliberate. Waiting. Ollie Beckett hears it first - because Ollie notices the things other people walk straight past. And what he notices is this: the signal is not random noise. Someone built a fingerprint into it. Someone who needs to be found.
With no mobile signal, no internet, and a mining company quietly redrawing the boundaries of three pastoral properties, the Codebreakers must solve a mystery using only the land, a paper map, and each other. City skills are useless out here. Out here, the only thing that matters is whether you know how to read the country. Ollie does. And he's heard something that someone very powerful needs to stay buried in the red dirt.