Adjustment
1.
Prepare a VSWR power meter for applicable frequencies and RF
power, and set the meter as shown in the following figure. Practice
test transmission for the adjustment as short time and least RF
power as possible. (Maximum power rating in canstant wave (CW)
mode is approximately 1/3 of one in SSB mode.)
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er met
w
VSWR po
eiv
ansc
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T
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A
Start adjustment from the highest operating frequency downward
by cutting adjustment element, both sides in same length, to de-
sired resonant frequency, least VSWR return at the frequency.
Since cutting the element in excess may skip desired frequency
and result in losing resonant frequency, cut the element little by lit-
tle.
* If VSWR cannot be better
If VSWR can not be lowered even though resonant frequency came
to be desired frequency by cutting the element, it is most likely that
the antenna is being effected by earth or near by nuildings. Then it
is advised to change antenna height or antenna location. Bending
the element downward from the balun can also change VSWR.
Adjustment element cutting chart
*Cutting adjustment element will raise resonant frequency.
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djustmen
A
t elemen
*The following chart shows resonant frequency change per 1cm
element cut
Frequency
W-8010
W-735
80m(3.5MHz)
4KHZ
4KHz
40m(7MHz)
7KHz
7KHz
20m(14MHz)
45KHz
-
15m(MHz)
40KHz
-
10m(28MHz)
70KHz
-
*Above values may change depending on surrounding environment
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Tw
> 120°
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Fig. A
Fig. B
Fig. C
Fig. D
Fig. E
3
