ENSYS 402MHz Moxon Directional Antenna (RadioSonde)

Moxon directional antenna made with 3D printed frame and fiberglass tube. It is quite sturdy and rigid.

The Moxon is a directional antenna system that is gaining in popularity because it offers three very distinct advantages over a typical two element Yagi:

• Small in physical size. The Moxon can be built using a very lightweight structure and wire elements, which will fit into a footprint about two thirds the area required for a conventional beam.  You can see by the measurements above that a 20 meter Moxon is only 25 by 9 feet.  Being a very light structure, typically made from wire and lightweight spreaders, it can easily be mast mounted on a lightweight pole, hoisted up in a tree from an overhanging branch, or turned vertically and ground mounted!  As such it also makes an excellent field antenna.

• Outstanding front to back ratio.  The Moxon’s front-to-back ratio models at greater than 30dB! Moreover, close-gap coupling enables the Moxon’s enhanced performance to be realized at lower elevation heights of only 1/2 wavelength.  As seen below, the Moxon exhibits a broad forward area combined with superior front to back.
• The Moxon is a 50 ohm antenna, generating a near perfect 1:1 swr without requiring any additional matching devices. It is also quite broadbanded allowing for effective full band coverage.