Horizontal Mounting:
The MFJ-1762 presents about the same mast-loading as a small
TV antenna. This means you can erect it high and in the clear using standard TV mast,
roof or chimney-mounting hardware, and a light-duty rotator. To avoid property damage
or injury, plan your installation carefully and follow the same safety guidelines that apply
to any TV-antenna installation. Be especially careful not to bend or mis-align elements
when raising the mast. If you stack-mount the MFJ-1762 with other antennas, allow 5'
vertical spacing between higher-frequency Yagis and 10' spacing between lower-frequency
Yagis. Mounting the MFJ-1762 (or any Yagi) too close to existing antennas may distort
the pattern--or raise the launch angle of your signal and compromise performance.
Vertical Mounting:
The MFJ-1762 may also be mounted vertically for FM (or for West
Coast SSB) operation. When mounting a single antenna vertically, precautions are needed
to ensure that the mast and feedline do not upset the antenna's VSWR and radiation
pattern. In order to prevent the mast from detuning the driven element, we recommend
using a 8' fiberglass "painter's pole" as a mast. This will provide a strong RF-insulated
support. Fiberglass poles are available at most large home-care centers. A wooden closet
pole will also work--if weather-proofed with a uV-resistant finish. To prevent the feedline
from detuning the driven element, run your coax down the boom to the reflector end, then
let it drop down behind the reflector and below the rotor. If needed, use a short length of
wooden dowel to extend the boom--this will keep the coax from hitting (and detuning) the
reflector. Note that these precautions are
not
needed if you use a stacked pair of vertical
beams. In this case, the vertical mast will be located mid-way between the antennas and
will not interfere. A stacked pair is always preferable for vertical installations.
Single Vertical Mount
Stacked Vertical Mount
Fiberglass Pole
Stacking Two MFJ-1762s:
For best stacking performance, use 5/8-wave antenna
separation. In most installations, a single 12' x 1-1/4" length of thin-wall 6061 aluminum
mast may be used to support both antennas. For horizontal stacks, the first antenna
should be mounted as close as possible to the rotor, and the second mounted at the top of
the mast. This will provide approximately 11' 6" of spacing. In vertical installations, a 10'
mast may be substituted with only a minor loss in gain with both antennas mounted at the
extreme ends of the pipe.
