How to measure loss in each FO connector using OTDR

 How to measure loss in each FO connector using OTDR

Typical losses on fibers:

Per 1Km fiber: 0.4-0.7 dB.

Slipring: 2-5 dB. –channel 1; 2dB max, channel 5; 5dB max.

Barrel (calculated including 2 connectors): 0.5-1 dB

Connector: 0.25 dB.

The Focal units require a minimum loss of 5 dB between units or the units will get destroyed, maximum loss unit to unit is 20 dB, any more than 20.5 dB and the units will not communicate, normal loss for a system is 12-16 dB.

The OTDR requires a “launch cable” of minimum 48 meters length as the unit is not able to read any information in the first 48 meters of fibers.

Attach the fiber launch cable to the top of the unit, attach the launch cable to the system using a barrel connector.

Press the red on/off button to turn unit on.

Unit will start in Standard mode (shown above).

Press Enter.

You will now arrive to the screen shown above.

Press f3 to choose the Wavelength of 1550

Press f4 to choose the length of fiber (always choose slightly longer than your total system length.

Press f5 to choose Display from origin.

Press f6 to jog through to next page.

Press f1 to choose 30 seconds test time.

Press f6 to arrive back to above page.

Press f1 and the unit starts testing the fiber, wait until the yellow icon to the left of the battery icon stops blinking.

Use the wheel on the top right of the unit to move the red scroll bar, click the wheel and a new scroll bar (blue) will appear, move this scroll bar in the same fashion.

The distance from the start point (the OTDR itself) and the first and second scroll bar are shown in the lower left hand corner of the screen, the loss between the scroll bars is shown to the right of the lower left box on the screen.

By moving the scroll bars you can now pinpoint the losses at the various parts of the system.