Start with the decision: Sudden or intermittent SWR changes usually point to movement, moisture, arcing, loose or corroded connections, damaged coax, unstable coil contacts, changing nearby conductors, or a protection/tuner relay fault rather than propagation.
What changes the result
Useful diagnosis separates source, feed line, matching, radiator, RF return, support/environment, and propagation instead of changing them together.
The mistake to avoid
A tuner can hide a symptom; SWR alone cannot prove efficiency, pattern, feed-line current, safety, or range. Never continue transmitting into an uncertain or arcing system.
Use this practical sequence
Record the symptom and known-good baseline, remove RF, restore one exact configuration, inspect and measure from radio outward, substitute one known-good part at a time, and document the correction.
Source boundary
Current Chameleon guides and controlled Field Handbook diagnostic practices. Use the exact current product, complete configuration, and applicable safety limits.
