MFJ 1798 - Page 16

MFJ-1798 Vertical Antenna Instructions
15
One 19" rod threaded one end
Six black cable ties
24- Thread a #10 nut 1" in from the outer end of the 19" element. Mount the 19" element in the
"2 meter element" hole of the counterpoise support plate (see page 11, figure 3). Insert the
threaded end of this element into the top of the hole so it sticks out ABOVE the top of the antenna
(away from the base mount and the other stubs). Install a second nut below the plate to secure the
element. Install this nut loosely for the moment!
25- Dress the long coaxial cable along the main element from the balun to the top of the antenna.
Ground the solder lugs near the balun end of the coaxial cable to the 1-3/8" diameter tubing by
placing one lug under the hose clamp and the other lug under the 1/4" base mounting bolt.
Tighten the 1/4" bolt snugly now. Ground the coax ground lugs to antenna along the feedline.
26- Secure the coaxial cable to the tubing by evenly spacing the black cable ties
along the cable.
Important:
Keep the Coax cable feeding at least 1-1 1/2" away from the antenna mounting
bracket. Failure to do so will cause arking problems on high power between the mounting
bracket and feedline, which could damage the feedline and possisbly your equipment.
Locate the following parts:
Four 1/4" x 6' aluminum tubing (A)
Four 4-40 x 3/8" screws (B1)
Four 4-40 flat washers (B1)
Eight 6-32 x 5/8" screws (B3)
Ten 6-32 nuts (B4)
Four counterpoise clamps without flange (C3)
Four counterpoise clamps with flange (C3)
One square aluminum plate with hollow center (C2)
Counterpoise wire (D)
Four counterpoise clamp wires
additionally: a soldering iron and a step ladder or other 5-6' tall support
27- Thread the four 4-40 x 3/8" screws fully into the cap nut at the end of each 1/4" tubing.
Do
not tighten them yet.
28- Place the top of the antenna on a high stable support (such as a 6' step ladder) before starting
the counterpoise assembly.
29- Prepare seven counterpoise clamps (four without the flange and three with the drilled
flanges). Thread a 6-32 nut down the head of each 3-32 x 5/8" screw. Install three 6-32 x 5/8"