S820E UG PN: 10580-00343 Rev. H B-11
Measurement Review B-5 Standard Line Sweep Measurements
B-5 Standard Line Sweep Measurements
To verify the performance of the transmission feed line system and to analyze
typical problems, three types of line sweeps are required:
• Return Loss
• Cable Loss
• Distance-To-Fault
The measurements for these sweeps are defined as
• Return Loss — System Sweep
• Cable Loss — Cable Loss Sweep
• DTF — Load Sweep
Return Loss / VSWR Measurement
Return Loss measures the reflected power of the system in decibels (dB). This
measurement can also be taken in the Standing Wave Ratio (SWR) mode,
which is the ratio of voltage peaks to voltage valleys, as caused by reflections.
Cable Loss Measurement
Cable Loss measures the energy absorbed, or lost, by the transmission line in
dB/meter or dB/ft. Different transmission lines have different losses, and the
loss is both frequency-specific and distance-specific. The higher the frequency
or longer the distance, the greater the loss.
Distance-To-Fault (DTF) Measurement
A DTF measurement reveals the precise fault location of components in the
transmission line system. This test helps to identify specific problems in the
system, such as connector transitions, jumpers, kinks in the cable, moisture
intrusion, or mechanical damage.
Line Sweep Measurement Types
Return Loss – System Sweep
Return Loss is the measurement made when the antenna is connected at the
end of the transmission line. This measurement provides an analysis of how
the various components of the system are interacting. It provides an
aggregate return loss of the entire system.
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