MFJ MFJ-6115, MFJ-6117, MFJ-6120, MFJ-6140, MFJ-6130 User Manual

MFJ-61xx Instruction Manual End Fed Zepp Antenna

INTRODUCTION

The MFJ version of the classic End-fed Zepp consisting of one ½ wave radiator and ¼ wave stub
is an antenna that delivers better than average transmitted signals even when installed at only ~¼
wavelength, above and it is directly-fed with any length of 50-Ohm coax. With the exception of
40-meter coverage (~150-200 kHz) no tuner is necessary for 15-20 meter operation with low
SWR across the band.

A further consideration is that this antenna is also quiet, when compared to inverted “V’s” (and
verticals, especially). A reduction of 2 – 3 “S” units of noise may make the difference in that
DX contact you can now hear above the noise!

End-feeding a half wavelength of wire has certain mechanical advantages over center-feeding
the same length of wire. It can be erected in limited space situations where a center-fed antenna
is not possible.

The added bonus: you can virtually “hang & play” this antenna as we construct them. No
tuning, trimming, etc. required. Just follow the easy installation instructions and suggestions, the
warnings, and you’ll be “up and running” in no time flat, and capturing DX, while receiving
signal reports as never before using lesser antennas.

Once connected, you’ll find the MFJ 61xx End-fed Zepp presents a low SWR across the entire
band. However, it is a “one-band antenna” depending which band you chose. Figure 1 is a
generic illustration of the antenna with its shorted stub and coaxial connection.

• Always mount or install antennas beyond the reach of adults and
children. Make certain your antenna installation meets RF
exposure guidelines

• Contact with exposed parts of this antenna system can cause RF
burns and other injuries.

• Constructing or erecting antennas where they may contact
electrical power lines can result in injury or even death

Warnings

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MFJ-61xx Instruction Manual End Fed Zepp Antenna

SYSTEM DESCRIPTION

L

COAX TO

F

X CVR 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.

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