Cable and Antenna Test Mode
R&S
®
Cable Rider ZPH
133
User Manual 1321.0950.02 ─ 07
The R&S Cable Rider ZPH displays a submenu to select measurement format.
3. Select "Normal" or "(Short + Open) / 2" menu item.
The R&S Cable Rider ZPH evaluates the cable loss over its entire frequency
(span) in dB.
The numerical result is the average cable loss over the specified span.
Figure 7-6
shows the typical results of a cable loss measurement with a steadily declining loss
over the selected frequency range and several maximums and minimums.
By default, the R&S Cable Rider ZPH evaluates the cable loss over its entire frequency
range (full span of the R&S Cable Rider ZPH). When you reduce the span, make sure
to define a span that is appropriate for the measurement, especially for high center fre-
quencies, and consider the cable length and the wavelength of the selected center fre-
quency. For a typical cable loss trace, you should select a span that is large enough to
evaluate at least one peak and one minimum. Otherwise, the result might not be valid.
If the cable loss is constant over a large span (for example in case of low center fre-
quencies), you can select any span.
However, if the cable loss is greater than 20 dB, you are better off using the (Transmis-
sion) S21 measurement, because the cable loss measurement might yield invalid
results.
Figure 7-6: 1-port cable loss measurement
7.1.4
Transmission Measurements
Transmission measurement (S21) is only available with model .12.
You can use transmission measurement to test if a radio signal can travel through the
line without losses. This type of forward transmission measurement helps to find faults
by displaying the magnitude of the reflections in dB in a specified frequency range.
Typically you perform transmission measurements on a filter to test if it works accord-
ing to the datasheet or test the isolation of two antennas (e.g. two receiving antennas
or a receiving and a transmitting antenna).
Performing Cable and Antenna Measurements
