Plain-language answer: RF in the shack usually means unintended common-mode current is flowing on coax, control, audio, USB, power, or grounding conductors.
Why it matters in the field
The cause may be antenna imbalance, inadequate return path, poor feed-line routing, insufficient common-mode impedance, station bonding, or resonant cable lengths.
What to do
Reduce power, confirm the antenna and return path, place an appropriate choke at the feed point, route cables away from the radiator, and trace remaining current cable by cable.
The common mistake
Treating a station ground wire as the universal cure for common-mode current.
Field boundary
Current regulations, safety clearances, equipment manuals, exact antenna geometry, and site conditions control. Test the complete installed system at low power before relying on it.
