Measuring Cable Insertion Loss
The SARK-110 provides direct measurement of the insertion losses of a transmission line.
The insertion loss measurement setup for a typical transmission feed line is shown in Figure 1. Remove the antenna and connect a “short” at the end of the transmission line.
Figure 1, Insertion loss measurement setup
In the example shown in the Figure 2, the analyzer was configured with the “Full HF” preset in order to sweep from 0.1 to 32 MHz. The measured loss minimum valley is at 842 kHz and has a value of 0.26 and the maximum peak is at 30.89 MHz and has a value of 2.89.
Therefore, the average insertion losses in this cable at this frequency range are:
Figure 2, typical insertion loss display in SARK-110 screen
The Field Mode is also very convenient for this type of measurement since it automatically provides the maximum and minimum values; see the Figure 3.
Figure 3, cable loss display in Field Mode
It is also possible measuring the cable insertion losses using the return loss parameter (RL). The procedure is the same as the described above but for calculating the insertion loss it is needed to apply the following formula:
The procedure in SARK Plots is similar. See in the Figure 4 a screenshot of the measurements of the same cable as shown in SARK Plots.
Figure 4, typical insertion loss display in SARK Plots