VE6DOK · The Missing Half
Counterpoise & RF Return
A counterpoise provides the RF return path. Without it, the antenna system will find an uncontrolled return path — usually the coax shield, radio, or shack.
What a counterpoise does
With counterpoise
- Controlled RF return path
- Stable tuning
- Better efficiency
- Less RF in the shack
Without counterpoise
- Coax radiates
- SWR shifts unpredictably
- Noise increases
- Station becomes part of the antenna
Counterpoise vs ground
| Counterpoise | Ground |
|---|---|
| RF performance system | Safety/protection system |
| Carries RF current | Carries fault or surge current |
| Length/layout can matter | Bonding and low impedance matter |
Starting length formula
Quarter-wave length in feet = 234 / frequency in MHz
Example: 7.1 MHz ≈ 33 feet. Cut long, measure, and adjust.
Visual concept
The counterpoise or radial field forms the return path for RF current.