Logical bus: hline:// + location_hash (persisted in hydrogen-line memory).
Visual RF: public OpenWebRX Web SDR UI — waterfall/spectrum at the receiver’s
public_ui_url. Same passive snapshot is hashed into the bus record; the SDR page is where you
see live band activity (tune/profile permitting).
Uses POST /api/hh-awareness-cloud action read_hydrogen_line_memory.
Idle. Click “Run mirror proof + load SDR view”.