Determining the length of an APC launch fiber

Problem

In case of APC, the only valid method for launch compensation is Manual Entry.

In order to do so, one must know the precise length of the launch and/or receive fiber.

Solution

It is highly recommended to measure the length of launch and receive fiber at the beginning of each shift, and to do so with the same OTDR as the one used during this test cycle.

Step 1: create your Auto OTDR test and set Singlemode' as Fiber Type.

Step 2: make sure Launch Compensation is set to the Off position.

Step 3: inspect-clean-connect the "launch" fiber to the SM port of the OptiFiber Pro.

Step 4: start a test and wait until it finishes.

In this case, the fiber has a length of 1006,6 meter.

Note: as the only parameters we'll be using is the fiber's length, there's no need for bidirectional testing.

Now repeat steps 1 to 4 for the "tail" fiber.

In this case, the fiber has a length of 1006,9 meter.

Now you have everything you need to set Manual Entry compensation.

Go to TOOLS > Set Launch Compensation > Manual Entry (APC) and tap SET.

Edit the cord lengths using the information obtained above.

Tap SAVE

You're all set.