BT603 Users Manual
24
In twisted pair cables, the VOP gets affected so much that it can twist the wires inside the cables. The insulation between two of the wires
increases with the increased twisting, which reduces the amount of air thus increasing the VOP.
For example, CAT5 cables are produced with twisting which adjusted by pairs in order to make it less vulnerable to crosstalk. It makes
VOP to deviate approximately by 2 %.
You can determine a cable’s actual VOP by adjusting the measured length to match a known length of cable.
1. Connect a known length of the cable to be tested to the tester’s twisted pair or coaxial connector. For maximum accuracy and
adjustment resolution, use a cable between 45 ft and 70 ft (14 m and 21 m) long.
2. Start the TDR test.
3. Adjust the Cursor2 to the point of reflection.
4. Change the VOP to get the length.
