Start with the decision: An antenna may not tune because the wrong recipe is assembled, a conductor is open or shorted, geometry moved resonance outside tuner range, the RF return is missing, common-mode current is uncontrolled, or the feed line/tuner is faulty.
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.
