Vectronics VEC-1862 - Manual (Page 6)

VEC-1862 Instruction Manual Six-meter Yagi Antenna
6
HORIZONTAL MOUNTING
The VEC-1862 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 VEC-1862 with other antennas, allow 5' vertical spacing
between higher-frequency Yagis and 10' spacing between lower-frequency Yagis.
Mounting the VEC-1862 (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 VEC-1862 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 VEC-1862s
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