SWR-584C Instruction Manual
HF/VHF/220MHz SWR Analyzer
10
As you change VFO frequency, the display will track any change in loss in real time (losses
normally increase with frequency). Remember,
Loss
mode is only accurate for 50-Ohm cable
or 50-Ohm devices, and these must be unterminated at the far end.
4.4 Measure Capacitance (pF):
This function measures the reactance of an unknown device
in Ohms (
X
) at a given test frequency and computes the component's capacitance value in
pF
.
To measure capacitance:
[ ] Turn on the analyzer and allow it to boot to default mode (
R&X
).
[ ] Press
Mode
twice
to access
Capacitance
and wait for the working screen.
[ ] Adjust the
Frequency
switches and
Tune
control to the desired test frequency (
MHz
).
[ ] Using the shortest leads possible*, connect the capacitor to the
Antenna
jack.
*Alternatively, use the same lead length used in the actual circuit to incorporate stray lead
inductance in your measurement.
[ ] Read
Reactance
(
Xc
) in Ohms on top line and
Capacitance
in
pF
on the lower line:
[ ] Also, read Reactance (
Xc
) in Ohms on the analog
Impedance
meter:
Ohms
40 50 70 100 400
0 10 20
The measurement range for
Reactance
is 7-650 Ohms. Outside that range, the analyzer will
display one of the following error messages:
Too low to measure (X<7) Series-resonant (X=0) Too high to measure (Z>650):
Sign Ambiguity:
In capacitance mode, the analyzer measures reactance (
X
) and the
operating frequency, then mathematically converts it to capacitance (
pF
). However, the
processor can't determine if the reactance sign is minus (-
Xc
). When in doubt, tune the VFO
up in frequency
and see if the value of
X
decreases
. If it
decreases
, the device is likely
3.500 MHz
71
C=
642 pF
Xc
Capacitance
in pF
10.120 MHz
C(Z)>650 Xc
3.500 MHz
C (X<7)
Xc
3.500 MHz
C (X=0)
Xc
3.500 MHz
C (Z>650)
Xc
