Start here: A balanced antenna can still develop common-mode current when its feedpoint, balun, feed-line route, element geometry, or nearby environment is asymmetric.
What the operator is actually controlling
Station bonding, earth grounding, lightning protection, RF return, and common-mode suppression are separate jobs. Adding a ground wire at random can create another RF conductor without restoring balance.
Use this sequence
- Restore equal element geometry and feedpoint connections.
- Use the specified current balun or choke.
- Route coax away from both legs as documented.
- Test at low power while changing one variable.
Do not make these substitutions
- Using low SWR as proof of balance.
- Adding a ground rod as a common-mode cure.
- Ignoring coax movement that changes the reading.
URT1 boundary
CHA URT1 User Guide 260524 and Applications Guide 260612. The current guide controls; direct ladder-line use is not presented as a supported URT1 connection.
