Greenlee 560XL Manuel D'instructions page 26

Two Test Jumper Method: Link Loss (cont'd)
3. Using the formula shown above, take the dBm reading on the optical
power meter (P3) and the nominal source output value, corresponding
to the light source in use.
Note: Make sure the optical power meter supports the wavelength of
the light source in use.
A
Test
jumper 1
P4
Power meter
4. It is advisable to measure the loss in both directions. Reverse the
source and optical power meter connections, as shown above.
Calculate the reverse loss using the formula shown above.
5. Report both forward and reverse loss values.
26
REVERSE LOSS (dB) = P2 – P4
Cable
plant
Test
jumper 2
Source
B