MFJ All Band Doublet Instruction Manual
1
MFJ-1777 All Band Doublet
INTRODUCTION
The MFJ-1777 is a multi-band center-fed dipole antenna capable of handling
1500 watts. It consists of a 102-foot “flat top” antenna fed with a length of 450
ohm balanced “ladder line.”
This antenna requires the use of a suitable matching network (antenna tuner)
with provisions for balanced-feed antennas, for interface with the 50-ohm
unbalanced antenna outputs of modern transceivers and amplifiers.
This antenna will work as supplied, as a centerfed antenna, on all amateur bands
80 through 10 Meters. On 160 Meters it can be used as top loaded vertical
antenna, with the dipole element acting as a capacitance hat on 160 meters (see
“160 Meter Operation,” page 3). Operation on 160 Meters in this manner
requires a ground screen or radial ground system, which is discussed on page 4.
This antenna
will not
work effectively in its center-feed configuration on 160
Meters.
TOOLS AND TIME REQUIREMENTS
This antenna requires no assembly. The time needed for installation will vary
with your skill and equipment. No special tools are required to install this
antenna. Nylon ropes are needed to support the ends of the antenna from
suitable structures or trees If trees are used, you will need a way to get ropes
over it. The most common method is to use a weighted arrow or a fishing rod
and a sinker to place a small line over a tree. A larger line is then pulled up and
used to pull the support rope over the tree. The ARRL Antenna Handbook has
detailed suggestions for installing wire antennas.
WARNING: Always mount antennas so that they are out of
the reach of adults and children. Contact with any part of
this antenna can cause RF burns or other injuries.
See the Safety Precautions on page 7.
