Propagation

VHF/HF audio-propagation characterisation from the rangetest harness — the platform's coverage curve, the model-vs-measured delta, and the audio-quality trend over time.

A sweep is a set of rangetest runs sharing a sweep=<id> note tag, run across multiple altitudes and lateral offsets. The 3D chart below renders the (lateral × distance) signal-strength surface — terrain shadows show as dips.
Propagation curve — attenuation vs distance

Model attenuation along the ladder, one line per altitude. Higher altitude reaches further — that is the radio horizon.

Measured vs model

Each received sample: model attenuation (x) against measured RMS in dBFS (y). The spread is the mixer/weather effect.

Audio quality over time

Mean received RMS (dBFS, line) and reception rate (%, bars) per run — the platform's audio-quality trend across dates.