Revised 14 June 2003
6
BOOM ASSEMBLY
Identify the 5-foot boom center piece, and place it on a table or bench for convenience.
The center piece is the only 3” diameter tubing that is swaged at both ends. Place the
boom center piece on the table with the handwritten instructions and legends facing up.
Note:
For assembly purposes only, the boom is upside down with the hairpin
matching sections and the elements above the boom. When the antenna
is actually installed, the hairpin matching sections and the elements will be
hanging below the boom, and the elastic stop nuts will be on the
underside.
1. Apply silicone grease to the boom center piece swaged ends, and to the inside of the
entire length of the boom coupler sleeves.
2. Slide the 3.25” diameter external coupling sleeves onto the ends, being sure to line up
the legends, and install in each the two 4” long quarter-inch diameter bolts, using flat
washers, finish side to the tubing, and elastic stop nuts. Tighten the nuts only enough
to prevent loss at this time.
Note:
Follow instructions on the coupler indicating location of the stop nuts. This
will assure that the nuts will be below the boom when the antenna is in
position for use. This is to make sure that even if a nut comes off, the bolt
will remain in the coupler, and that the elastic material in the stop nut is not
directly exposed to the sun.
3. Apply silicone grease to each boom end piece and slide it into the appropriately
marked coupling sleeve. Install the bolts loosely as above.
4. Install the boom mounting plate at this time, with the plate under the boom, and with
the nuts for the U-bolts left relatively loose. Place some soft material, for example, a
piece of scrap carpet, under the boom mounting plate. This will help control the
boom during assembly, and will allow rotation for the leveling operation to come a few
steps later.
Note:
The most popular mast diameter is 2.0" O.D. The mast plate supplied as
standard with the 2D-40A is for this size mast. If necessary, a mast plate
for other mast sizes can be supplied, or the supplied plate can be drilled to
accommodate the necessary size of U-bolt for the different size mast.
Contact the factory for custom mast plates.
5.
Install the phasing line as follows:
Place the dual coaxial phasing line through the boom, being careful to clear those
bolts already installed. Bolts can be removed and replaced one at a time to facilitate
installation of the phasing line. Take care not to damage the cable when replacing
the bolts.
