Measuring Electric Length Of Cable - Deepace KC901V Manual

During the measurement, every measurement data can be saved by using the
combined key SHIFT+1 and the saved data can be used for analyzing after the meas-
urement. In order to reduce the complicity of the operation, KC901V will name the
files names automatically according to the order of the file time. If there are many
files and it can be confusing easily, user can save them by using the combined key
SHIFT+3. In this time, users can name the file names by themselves.
If the antenna gain needs to be measured, set the reference antenna, which the
gain is known, on the stand of the under-the-test antenna. After it, adjust the orienta-
tions of the reference antenna and the testing antenna (make the reference antenna
aligns the under-the-test antenna according to the gain orientation which is already
given). Then do the user calibration in S21 mode and keep the setting parameters of
the instrument. Then replace the reference antenna with the under-the-test antenna.
Then test and record its S parameters in every different angle when it turns. In this
time, we can get antenna gain in different angles by adding tested parameter and the
gain of the reference antenna together.
Pepeat the steps above if you need to test the directivity diagrams and gains in
different frequencies.
Frequency can't be changed during the test, otherwise user calibration will be
useless and the data will also lose the relative meanings. While testing, users need to
stay away from the antenna. If the under-the-test antenna needs to be turned by
people, users can only read the data after turning the antenna and stay away from it.
When using two pc of KC901V, they can make a scalar network testing system of
single frequency point by setting one of KC901Vs in signal source and another one in
FIELD mode. This system can be used when two antennas are in a long distance. One
of the KC901V, which is used for emission, it can also be replaced by a transmitter
which has a steady power level. Since the isolation in this way is better than the in-
ternal insulation of single instrument, it can satisfy some testing applications which
need the large dynamic range (in the same way, users can use a PC to control two pcs
of KC901V at the same time if they need the larger dynamic range to do other S21
tests).
4.3 Measuring Electric Length of Transmission Line
When the transmission line's end is in open circuit or short circuit, user can use
KC901V to measure its electric length. In S11 mode, adjust it into PHASE display and
take the part of the curve which is smooth and the periodicity is obvious. Then meas-
ure the frequency difference length (Δλ) after the phase rolled one circumference
(The difference between two cursors' frequencies is nearly 0°). After it, you can get
the electric length of the transmission line. Of course, user can also measure the fre-
quency difference length after the phase shifts 180° .Then divide it with 4 to get the
result directly, or try to get the result by measuring two frequency difference length
after two 360°.
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