ation of a feed block or center insulator that is about 12 inches vertically by 3 inches wide, so make sure this is made of a good insulating material such as Lucite, Bakelite, fiberglass, or PVC. The end 38 inches of separation can be maintained by separate halyards on each element or a spreader bar with a common halyard.The bandwidth will be at least plus or minus 2% for a 1.5 to 1 SWR according