Shield performance during the life of the cable is an important consideration especially in drop cables. Aerially installed non - messengered drop cables are subject to vibration and sway from wind effects, which can degrade the performance of the shield over a prolonged period of time.

Flex life is generally less critical for messengered cable than for non - messengered cable. This is due to the rigidity of the messenger which significantly reduces the amount of flexing and vibration the cable is subjected to in real world conditions. For this reason, flex testing is most commonly performed on non - messengered cable.

To examine a cable's ability to withstand flexing in a laboratory environment, tests were conducted as shown by the diagram. The cable was mounted and flexed between the extreme positions shown for the reciprocating arm.

Cable is clamped at both ends. Clamps are attached so that they freely rotate on mounting ends.

Flex Test Results
After cable flexing, the highest values of transfer impedance occur at the highest frequencies tested (illustrated below). This is where the greatest overall degradation occurs. Throughout the flexure range, Duobond® Plus had a lower transfer impedance value at higher frequencies.

The test data conclusively demonstrates Duobond Plus® performance is superior to other cable shield designs currently used by the Broadband Industry. Belden cables shielded with Duobond Plus can withstand repeated flexing and still provide the most shield effective drop cable in the market today.