A helical-beam antenna without a ground plane

The helical-beam antenna (a.k.a. axial-mode helix), which the author devised in 1946, was fed via a ground plane. This arrangement has proven very satisfactory for many applications. Now, almost 50 years later, he presents a version in which the ground plane is replaced by one or more loops. This design is well suited for pole mounting. It has less wind resistance, and presents a much-cleaner appearance, while providing equivalent performance to a helix with ground plane. The new version retains the broadband and non-critical nature of the ground-plane helix to a marked degree.<>