- 7 -
Figure 7 - Marking the tube
A good suggestion is to mark the position of the trap with a pencil before starting so that returning
to the initial point will simply a matter of lining up the marks or referring to
Figure 6
.
Always start with the 10 meter trap because any adjustment done there affects the rest of the
antenna. If the 10M section requires no further adjustment move up the antenna to the 15M trap,
then the 20M trap, etc.
Slightly loosen the clamp that secures the trap cover to the tubing as seen in
Figure 8
. Grasp the
trap at the end with the black plastic cap and exert a slight twisting motion while at the same time
moving the trap cover up or down depending on whether the frequency needs to be higher or lower
(
Figure 9
).
Figure 8 - Trap Cover Clamp
Figure 9 - Adjusting the Trap
The typical movement usually works out to about 1/8 to 1/4–inch but sometimes more is needed.
1/4 to 1/2 inch of adjustment will result in about 500 kHz of change. Firmly tighten the trap clamp
and re-test the antenna for resonance. Continue this procedure until the antenna has resonance near
the desired frequency.
Note:
Be sure that the connection between the trap cover and the tubing is clean and the clamp is
tight. Some surface film may have developed on the BTV tubing over-time. Poor connections here
can cause erratic readings.
Next, move up the antenna to the each successive trap and make similar adjustments until the
antenna resonates near the desired frequencies. Fine tuning can be accomplished by adjusting the
tubing dimensions of each section as described in the Hustler installation instructions.
