SWR-584C Instruction Manual
HF/VHF/220MHz SWR Analyzer
9
[ ] Read
Impedance Magnitude
(
Z
) on the analog meter scale.
Ohms
40 50 70 100 400
0 10 20
[ ] Read
Impedance Magnitude
(
Z
) and
Phase Angle
( ) presented numerically by
pressing
and holding the
Gate
button.
The LCD display changes, as shown below:
[ ] Release
Gate
to revert back to
R&X
.
Note that
Reactance
readings (
X
) could be
inductive
(
+ X
L
)
or
capacitive
(
- Xc
) because the
processor can't calculate the sign. However, you can often find the sign by installing a small
capacitor across the feedline connector to add a few ohms of capacitive reactance. If your
capacitor increases
X
, the load is likely capacitive (
-
) because
your
reactance added to it. On
the other hand, if your capacitor caused X to decrease, the load is likely inductive (
+
)
because
it cancelled out some of the
X
. To ensure accuracy, keep the amount of
Xc
you add as small
as possible.
Also, when measuring through a feedline, always remember the values for
R, X, Z, and
are
displaced values measured
at the analyzer's calibration plane
and
do not represent the actual
impedance of the device connected at the far end.
To read the impedance of the device under
test accurately, you must connect directly to the DUT using the shortest leads possible (or use
an electrical half-wave of 50-Ohm cable) .
4.3 Measure Coax Loss (dB):
This mode displays the
Measured Loss
in
dB
at the
VFO
operating frequency for any length of 50-Ohm coax cable. It will also measure losses incurred
through 50-Ohm attenuators, transformers, or baluns. To measure
Loss
:
[ ] Turn on the analyzer and allow it to boot to the default mode (
R&X
).
[ ] Press
Mode
once
to access
Coax Loss
and wait for the working screen.
[ ] Adjust the
Frequency
switches and
Tune
control to the desired test frequency (
MHz
).
[ ] Connect the feedine under test (or 50-Ohm device) to the
Antenna
jack.
[ ]
Make sure the far end of the coax or the output port of the device is unterminated
.
[ ] Read Coax Loss on the lower line of the LCD display:
10.120 MHz 1.5
Z= 75 = 5° SWR
10.120 MHz 1.5
R= 73 X=10
10.120 MHz
Coax Loss = 2.1 dB
