Figure I
Overall View
Figure 2
Front and Rear Boom Detail
Tuning
NOTE: The Driven and Parasitic Elements are
adjusted independently in the following
manner.
Parasitic Elements: This antenna is pretuned
for maximum gain and best radiation pattern
at 144 MHz. This setting will give good
performance over the entire 144-148 MHz
band.
If you wish to optimize the antenna for a
frequency higher than 144 MHz, cut l/4" off
of the total element lengths for each MHz
higher than 144 MHz.
Driven Element: SWR can be lowered to less
than 1.2:1 at a desired frequency by
carefully trimming the driven element. Keep
the element symmetrical by cutting the same
amount from each side. Typical SWR curves
are shown in Figure 3A, and a cutting chart
is shown in Figure 313. Each installation is
slightly different, so cut the driven element
for the lower SWR at your particular
location. Measure the SWR as close to the
antenna as you can for accurate results.
