Chapter 6 DTF Testing
CellAdvisor JD720C Series User
’s Manual
59
Performing calibration
Perform an O-S-L or Quick calibration by pressing the
CAL
hard key. The instrument
displays on-screen instructions for you to follow through. See
page 33 for more information.
Making a measurement
Once the O-S-L or Quick calibration is done, the instrument is now ready to make a DTF
measurement in VSWR or Return Loss. If you like to not only measure the DTF cable length
but also get highly accurate and reliable data, you need to perform a full O-S-L calibration.
Procedure
1
Disconnect the calibration kit from the calibration point.
2
Connect an antenna or feed line to the calibration point, where is usually at the extension cable
end if used. See
for the cable connection diagram.
3
Your measurement result is displayed on the screen in real time.
NOTE
If O-S-L or Quick calibration has been done at the end of the port extension cable for DTF
measurement, the length of the port extension cable is compensated automatically and is
not included in the distance to the point of discontinuity.
CAUTION
Do not apply or connect power exc25 dBm to the
RF Out / Reflection
port. When
the input signal power is greater than +25 dBm, the input power protection is triggered to
protect the instrument and a measurement comes to stop automatically.
Figure 27
Cable connection diagram for DTF measurements
JD723C/724C
JD725C/726C