Phased vertical array

phased vertical array 40mtr

Recently i came across some audio and video files about my vertical array antennas i developed for contest purpouses. While constructing and researching those arrays i found plenty of materials with brilliant ON4UNs Low Band Dxing book. But unfortunately i found almost no files of accual performance of such antennas. On the other hand i was so surprised how well it can perform that i’ve decided to put some short video of it.

My phased vertical array is two element’s vertical array working on 7MHz (40 meters band). It consist of two ground plane quarter wave antennas spread 1/4 wave away. Both are ground based and are working over extended radial field of 80 radials 8 meters long. Directivity is achieved with Christman phasing method. It uses coax cable delay line of 71 degrees long (while quarter wave is 90 degrees) and verticals are feeded with 84 degrees lines from the junction box.

Christman method is widely known and described over in various publications and websites so let me skip the details and show you the video. The station in the background is OK1AYD calling CQ in some contest. Switching antenna from South to north giving me some nice Front to Back ratio as well as some gain over dipole. The F/B depends on various factors including direction and angle of incoming signal.