The ARRL Handbook (Straw 2003) defines counterpoise as: “A wire or group of wires mounted close to the ground, but insulated from the ground, to form a low impedance, high-capacitance path to ground. Used at MF and HF to provide an RF ground for an antenna
“
The article about “counterpoise” by Owen Duffy, VK2OMD ex VK1MD addresses many issues with the term. “Counterpoise means all things to all hams, because of its lack of clear and unique meaning, wise authors avoid its
use. Let’s explore a rational meaning based on the roots of the word. It has two roots, counter and poise:“
- counter means in the opposite direction
- poise means in a state of balance.
Today’s amateurs are using the term counterpoise so often, especially when it comes to EFHW antenna, and fail to learn that a single hanging wire (pigtail) attached to the coaxial shield of the 50 Ohms Coaxial connection at any transformer is NOT:
“Presenting low Impedance, the high-capacitance path to ground.“
So what is the “counterpoise” needed to balance the EFHW antennas? The simple answer is: NONE! The EFHW antennas will always find the path to low impedance. The most common path is via coaxial cable shield connected to low impedance path such as grounding at the entrance to the home as mandated by national electrical code NEC-810. Even in the case when the coaxial cable shield is not connected to the secondary winding of the transformer, the path to lower impedance will be achieved by DISPLACEMENT current, see the test showing no change in VSWR measurement with or without of coaxial cable shield used as “Counterpoise”. The video is at this link https://www.youtube.com/watch?v=7bm0c_CNtVU
The Counterpoise article by late W4RNL starts by:
The term counterpoise has a long history in antenna engineering and amateur practice. Today, it may be among the most misused terms in amateur circles. Indeed, if we examine both the history of the term, its meaning, and its misuses, we might reach an interesting conclusion: there is no such thing as a counterpoise in antenna analysis, even though the term has a long and somewhat respectable use in antenna engineering.
