MFJ-61xx Instruction Manual End Fed Zepp Antenna
2
SYSTEM DESCRIPTION
L
F
COAX TO
XCVR OR
REMOTE
SWITCH
Figure 1
End-fed Zepp
SYSTEM DESCRIPTION
Dimension “L” represents a ½ wave, and “F” represents a ¼ wave, which, in this case is a ¼
wave stub, used for matching. The MFJ 61xx End-fed Zepp is a basic “
broadside
” radiator and
is broadly bi-directional perpendicular to the run of the wire. A pair of these antennas at right
angles (NE/SW; NW/SE for example) can provide world-wide coverage. And, when used with a
suitable antenna switching system (Ameritron RCS-10), switching is convenient and fast, with
only a single-line feed into the shack. Or, you can run both coaxial lines into the shack, and
effect switching with a wall-mounted switching unit (MFJ-1700).
If height is a constraint, this antenna functions better than average at even a bit less than a ¼
wavelength above ground/structure. However, it really performs best if “hung” at a ½ wave; up
to ¾ wave. Higher than that provides diminishing return.
Especially important is keeping the symmetry of the antenna in reference to its ½ wave radiator.
They must not sag more than a foot, with pulled-tight being the best configuration. The
feedline/stub can be “bent” at the bottom, or pulled away at a slight angle, and some twisting is
OK. Practically, it is best to let it hang straight down and tie it off with rope to avoid lashing
about in windy conditions.
