Revised 14 June 2003
3
ASSEMBLY
ELEMENTS
This antenna has been sub-assembled at the factory and then disassembled for
shipment. However, it is a good idea to check the measurements on the elements during
assembly. The important measurements are those of the exposed lengths, that is, from
the outer edge of an element component to the outer edge of the next larger one. The
centermost element pieces (the ones that include the feed point terminals) are exposed
for their entire length. Element exposed lengths can be found in APPENDIX C. The
exposed lengths also appear in APPENDIX D, PARTS LIST.
Elements are stepwise tapered by using smaller diameter, thinner-walled tubing going
from the center toward the tip. The first two joints of each half-element are bolted.
Pieces farther out are swaged (at the last several inches farthest away from the center
of the element) down to the outer diameter of the next smaller element piece.
Sometimes the amount of size reduction due to the swage is just a few hundredths of an
inch, however, the swage is visible. The tip pieces fit into the swaged and slotted ends of
the next-to-last pieces, and are continuously adjustable for coarse frequency setting.
Element pieces have been marked for re-assembly with markings on both sides of each
joint.
Note:
Element naming and marking convention is as follows: Imagine that you are
standing at the front of the boom looking toward the rear of the boom.
When the beam is installed for operation (hairpins, element mounting
plates, and elements below the boom), the front half-elements will have "A"
markings to the left and "B" markings to the right. The rear half-elements
will have "C" markings to the left, and "D" markings to the right.
The left front half-element begins with A1-A1 at the center fiberglass connecting piece,
then A2-A2 at the next joint out, then A3-A3, and so on. The other half of the element
begins with B1-B1, and is marked in a similar pattern. The rear element markings are
C1 and D1 at the center.
Important Note:
Be SURE to align the hand-marked legends on all joints.
Legends are hand-marked on both sides of every joint. There
are three rows of rivets, only one of which has the legends.
The row with the legend is also the only row that has the small
drain hole in line with it. All three rows will be perfectly aligned
if and only if the legends are aligned.
Note:
Elements are usually assembled as half elements, then are joined at the
center prior to mounting them to the boom.
Prepare a sturdy table or bench for antenna assembly.
Unwrap black tape to release element pieces.
