Topband: Broadband vertical

[Steve Lawrence]

Here's my experience:

54 ft freestanding 3-section shunt fed tower. 15 elements from 3 
antennas stacked on the mast. More than half of the elements as-built 
are DC isolated from the booms/mast.

3/8 inch aluminum gamma rod 15 inches from one tower leg. Rod runs from 
the base to the top of the bottom section only at 22 feet. No dangling 
wires when the tower is down. No radials either as there is no place 
for them on my city lot.

Vacuum variables in an omega match. Tuned for 1828 +/-

1.5:1.0 bandwidth useable from below 1810 to near 1840. Tuning is very 
critical but easy with the vac variable's verniers.

Useable within other band segments by adjusting the omega match for the 
highest frequency and switching in additional capacity for the lower 
desired frequency.

I do exactly that to use the shunt feed for both 80 and 160. Heavy duty 
RF switch is at the tower base.

The omega match is much easier to use than adjusting the tap point and 
gamma wire spacing, especially when you don't have a lot of room and/or 
you don't want multiple trips up the tower.

You won't know what you actually have until you just try it. Mine 
works. YMWV.

73 - Steve WB6RSE