MY 40 METER WIRE FOUR SQUARE VERTICAL ARRAY

 THIS PICTURE IS ONE OF MY 40 METER GROUND PLANE ANTENNAS USED IN MY FOUR SQUARE VERTICAL ARRAY, NOTICE THAT I USE ONLY TWO RADIALS ( THE BLACK DOT IS A COAX RF CHOKE )

 

  

THIS PICTURE IS MY VERY SIMPLE FEED POINT CONNECTION. THE SPLIT-BOLT IS USED TO SECURE THE COAX ALUMINUM SHIELD TO THE # 12 COPPER WIRE RADIAL. PENETROX IS USED TO ASSURE THERE ARE NO PROBLEMS WITH THE DIFFERENT METALS.

I constructed my 40 meter four square vertical array using four full-size 40 meter ground plane antennas, but using only two radials. The ground planes are constructed from #12 copper wire and each antenna base is elevated 29 feet above the ground. I am using coax RF choke baluns at the feed points instead of ferrite beads. The beads can cause several problems: power loss, phase shift, (THE BIGGIE on a phased array) and can be permanently saturated by close lightning strikes…etc. The coax RF choke baluns eliminate RF currents from flowing on the outside of the coax cable. This assures the ground plane is doing the radiating and not the feed line. This also HELPS to prevent array pattern distortion and increases the F/B ratio. The coax RF choke baluns are constructed of RG-6 coax, 13 turns, in a 4 inch diameter and single layer. DON’T “bunch the turns” as this will eliminate the choking effect. I am using a split-bolt to secure the aluminum shield to the radical wire along with penetrox, to prevent possible problems with unlike metals. All the connection is then sealed with coax seal.
 
PERFORMANCE:
 
After several antenna tests, the ground mounted system seems to out perform the ground planes by about 3 to 8 dB as far as F/B is concerned. However, the gain of both arrays seems to be about the same, approximately 6 to 8 dB over my reference antennas. I am using a Comtek phasing system built by Jim Miller, K4SQR, for both four square arrays.

UPDATE: I understand Jim sold The Comtek Company to DX ENGINEERING

 

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