The attenuation per foot or meter for the cable is also required in order to compensate for the attenuation versus distance.
Likewise the cutoff frequency and waveguide loss are required for DTF, measurements of waveguide transmission lines.
For example, connector corrosion can be detected early and weather seals replaced before moisture destroys expensive cables.
DTF finds these problems because the FDR technique can accurately detect very small performance changes within the transmission line.
Since DTF automatically accounts for attenuation versus distance, the display accurately indicates the return loss or VSWR of the antenna.
In a Wireless Communication System, tower mounted transmission lines and cables are replaced frequently, perhaps every five to ten years, in some cases.