Agilent Technologies HP 8719D Service Manual page 326

Load Match (ELF and ELR)
Load match is a measure of the impedance match of the test port that
terminates the output of a Z-port device. The match of test port cables is
included. Load match error terms are characterized by measuring the Sll and
Significant System Components.
load match error terms may indicate a bad U thru n cable or a poor connection of
the cable to the test port.
Affected Measurements.
errors are all transmission measurements, and reflection measurements of a low
insertion
loss two-port device, such as an airline.
Large variations in the forward or reverse
The measurements most affected by load match
Figure 11-5. Typical ELF/ELR
Error Terms 1 l-13