[TowerTalk] Gamma-matched 4-square

[Scott W3TX]

John ON4UN addresses this question in "Low Band DXing".

His advice was to avoid shunt fed elements in a driven vertical array.

If the elements are dedicated  (ie. not a shunt fed tower) then it is really 
very easy to end feed the elements (insulated from ground):

Use a 6" piece of Garolite, or other suitable FRP rod, machined to telescope 
into the bottom section of aluminum tubing.  Pour a small concrete pad 
(perhaps 1ft cubed) base for each vertical element and during the concrete 
"set" impress the FRP rod 2" deep into the center of the pad.  A few days 
later sleeve the FRP rod 2" into the bottom aluminum section and cross bolt 
it in place.  Thus there is a 2" gap between the element bottom and the 
cement pad. One of the bolts can be used as a simple connector for the coax 
center conductor. Place three ground rods around the circumference of the 
concrete pad. Cadweld a circular piece of plumber's copper tubing to each 
ground rod. Connect your feedline ground to one of the rods. Connect your 
radials (60 to 120 recommended) to the copper circle. Now you have a simple 
and cost effective base insulated element.  If you ever take it down just 
pull the FRP out of it's indentation in the concrete and the FRP goes with 
you!

73, Scott W3TX