User’s manual
Adjusting the antenna
When the measurement diagnoses that the antenna is off the desired frequency, the
analyzer can help in adjusting it. Physical dimensions of a simple antenna (such as a
dipole) can be adjusted knowing the actual resonant frequency and the desired one.
Other types of antennas may contain more than one element to adjust (including coils,
filters, etc.), so this method will not work. Instead, you may use the
SWR mode
, the
All parameters mode
or the
Smith chart mode
to continuously see the results while
adjusting various parameters of the antenna.
For multi-band antennas, use the
MultiSWR mode
. You can easily see how changing
one of the adjustment elements (trimming capacitor, coil, or physical length of an
aerial) affects SWR at up to five different frequencies.
Coaxial lines
Open- and short-circuited cables
The pictures on the right show
R and
X charts
for a piece of cable with
open- and short-circuited far end. A
resonant frequency is a point at which X
(reactance) equals to zero:
• In the open-circuited case, resonant
frequencies correspond to (left
to right) 1/4, 3/4, 5/4, etc. of the
wavelength in this cable;
• For the short-circuited cable, these
points are located at 1/2, 1, 3/2, etc.
of the wavelength.
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