MFJ 1798 - Page 4

MFJ-1798 Vertical Antenna Instructions
3
Never
mount this antenna where a mechanical failure might allow the antenna to contact power
lines or other utility wires.
Always
ground the feed line at the point where it enters a building to a good earth ground for
lightning protection.
MOUNTING LOCATION
WARNING: Always mount this antenna so that it is out of the reach of adults as well as
children. Contact with any part of this antenna can cause injury and / or severe RF burns.
The ideal antenna mounting location is an open area either above or more than 70 feet away from
other large conducting objects or antennas. If such a location is
not
available, the least obstructed
location should be selected.
This antenna should be mounted on a rigid support. The mounting clamps supplied with this
antenna accept masts between one and 1.5 inches outside diameter. Additional holes in the mount
of this antenna will accept mast clamps up to 2" OD. Soft or thin wall masts should not be used
to mount this antenna to any supporting structure.
The MFJ-1798 will perform quite well in ground mounted installations. The lower end of the
antenna should be at least 5 ft above ground level. If the antenna is ground mounted, it MUST be
surrounded with a protective non-metallic fencing. This will increase the safety and lessen the
likelihood of damage to the antenna.
GROUNDING
Unlike most verticals, this antenna does not require an RF ground system. However, some sort of
earth connection is a good idea to avoid lightning damage to the station equipment and to
improve operator safety.
The feedline's shield should be grounded at the entrance point of the building before it reaches
the operating position. Failure to do so can result in lightning damage to the equipment. This will
also help prevent voltage from being applied to the antenna support if the station equipment ever
develops a problem.
Additional lightning protection can be achieved by burying the feedline directly in the soil for a
minimum of 10 feet before the cable enters the building. It is also an excellent idea to ground the
mast or supporting structure.
Grounds should consist of multiple rods driven into the soil. Several long straight buried wires
will assist in dissipating lightning strikes. Leads from the ground system to the antenna mast or
coaxial cable should be as short and direct as possible. Sharp bends in the ground leads should be
avoided. It is an excellent idea to connect all the grounds together outside the building with