A MORE EFFICIENT MAGNETIC LOOP ANTENNA

Variations on a Theme Continued

Glen E. Gardner, Jr.

AA8C



Updated 8/17/2014


For the last five or so years, I have been using a rather different magnetic loop antenna. It was built with improved efficiency in mind, and it has served as a configurable testbed for experimentation. I have withheld most of my comments regarding this antenna because I felt that I did not adequately understand why, and how it was more efficient. Over time I began to understand this antenna a bit better, so now I have decided that it is a good idea to share some of the things that I have learned from using these antennas on a daily basis.

The idea behind this antenna was to use multiple conductors in parallel to reduce the resistance losses in the antenna , and thereby improve the efficiency. At the time I began working with this problematic design, there was no complete model for it. What I found was that not only did multiple parallel conductors increase the efficiency of the antenna, they increased it by quite a lot more than I had initially expected. Also, I learned that there are limits imposed on the benefits of such a configuration and that there were also some surprising changes in the behavior of the antenna when using multiple parallel conductors.

The antenna pictured above is an evolution of the original antenna built with improved efficiency in mind. Tests indicate that this antenna is at the limit for significant improvement in efficiency by adding additional parallel conductors.

The initial design from about 2008 was posted on the internet to encourage others to experiment and to