• UNITED TRANSFORMER CORP

•
FIG. 2 -
:\Ie thod of feed
point which is the end with the No. 6 element.
Table I-Dimensions of LPD array
Length of Spacing from
Element Feed-point
A I = 81 20.8 in. 60.3 in.
A2 = 82 19.0 46.0
A3=83 17.4 33.0
A4 = 84 16.0 21.0
A5 = 85 14.6 10.0
A6= 86 13.3 0
The boom length is 72 inches so that the
boom will project past the last element 11.7
inches. The two booms are shorted together
at this point (see Fig. 2) .
The antenna is fed with 72 ohm coax
cable at the feed-point, with the center conductor
attached to one boom and the outer
sheath to the other boom. It is recommended
that the coax be inserted in the lower boom
as shown in Fig. 4 but it can be taped under
the lower boom with only a slight decrease in
performance,
•
Our f irst attempts ot securi ng the elements
to the booms were very satisfacto ry but
more costly thon the method outlined in the
article
Feed point of the antenna and view of
the first element and separato r block.
The two booms are separated by a distance
of ~ inches throughout their length. This is
done by making two separators and one
mounting block. Wood, preferably hardwood,
can be used for this. Two pieces of 2 x
2 lumber, 3); inches long and one piece of 2 x
4 lumber 6 inches long, are required. Two %
inch holes are drilled centrally in each block,
spaced 1 ~ inches center-to-center in the 2
inch face. Two additional 14 inch holes are
made in the blocks so they can be clamped
together when sawed apart, as shown in Fig.
3. The boom is clamped by the three blocks,
and holes are drilled in the center 2 x 4
block to accommodate two TV mast U~
clamps on the 4 inch face. All the wooden
parts are then coated with 2 to 3 coats of
exterior varnish.
FlG. 3
S aM>
c...t
=6+ ~.
--.- .- I ,
-'-
Separator bloc k
FIG. '!
S l ll.