In plain language: Feed-line radiation occurs when unintended current flows on the outside of coax or when a balanced line is routed or fed asymmetrically, changing the antenna system and bringing RF into unwanted places.
Why an operator notices it
A feed line that radiates can distort the pattern, make tuning sensitive to cable movement, raise local noise pickup, and put RF on the operator or equipment.
Decisions that matter
- Verify the intended RF return and feedpoint symmetry.
- Use documented choke or balun placement.
- Keep the line clear of radiator elements and asymmetric nearby conductors.
A useful field check
- Test whether moving the line changes SWR or noise.
- Measure common-mode current when equipment is available.
- Restore geometry before adding suppression.
Common wrong turns
- Assuming all coax radiation comes through the shield.
- Blaming the cable before checking the antenna return.
- Using a tuner to hide the symptom.
Technical foundation
This lesson translates established transmission-line and antenna practice into a field decision. Use the current equipment datasheet and Chameleon product guide for changing loss, power, connector, installation, and compatibility limits.
