This antenna was introduced to me during a QSO on 20m SSB a few years back. At the other end the operator said for an antenna he was running a 4 foot vertical. That caught my interest since he had a really strong signal. He explained that it was a double wire loop where the vertical sides were only 4 feet tall. I wanted to know more about it. Who doesn’t want to know about a small antenna that radiates well in this day of antenna restrictions. Here’s a figure from an article about the antenna so you can see what we are describing:
The ham I was in QSO with referred me to an article describing the antenna in the ARRL Antenna Compendium Number Two by Russell Prack, N5RP. It is titled “Magnetic Radiators–Low Profile Paired Verticals for HF” on page 39.
Soon I built one for 20 meters and it was a great performer as expected. It was super quiet. Without planning it, I had accidentally constructed the antenna so it nulled out the power line noise here. There’s not much gain but the noise is so low that the antenna has a fantastic signal-to-noise ratio. Gainwise, it looks like a four square and that gives it good gain. But it is using short radiators so that lowers the efficiency and there goes the gain. It all evens out in the end and radiates quite well, however.