Does my EFHW antenna need a counterpoise?

Counterpoises and End-Fed Half Wave antennas. Sigh. The magic forest of hidden fairies and other fancy tales.

To start, I want to mention one allegory that might help explain what is happening in the antenna system. It is my “old” guitar string story.

Imagine the radiating wire (sometimes the Chinese call it the “vibrator”) to be a guitar string that is held tight at the two ends, and depending on the tension it will produce a tone at a specific frequency when plucked or disturbed. When you move the end-points, or change the tension, the note changes.

Well, that is your antenna wire. Now at the far end it is held tight by the Open Circuit (a sudden stop for the electrical signal). A short or an open circuit on a transmission line works like that.

But by the coax end the vibrator (or guitar string) is _*not*_ held tight if it is only a coax, because there is nothing for the electrical signal to bounce against except a piece of coax, the starting point of which is electrically somewhat undefined. A proper counterpoise could serve as the required stop at the end-point. Of course, the coax braiding can help and will help, but it is not a sharp enough point to be really effective.

Stimulating that piece of vibrating wire at the correct frequency and amplitude is your main objective. Just imagine in your head while looking at the wire: Imagine it moving in your minds eye. And keep in mind the two end-points that are holding it tight.

The rest of the gear: The coax, the balun, etc are simply the tools you use to stimulate the radiating wire. If the vibrator or radiating wire isn’t able to vibrate, you can not emit a clean “note” or signal.

So that is my parable for today to help you understand the EFHW antenna counterpoise.

Enjoy your hobby!

73 Leon