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1205CXB OPERATION MANUAL v1
© Copyright Radiodetection Ltd 2022
20
Return Loss
The 1205CXB provides you with a numerical measurement of the severity of a fault. This is called the
Return Loss and it is measured in dB.
Return Loss is a ratio of the amplitudes of the reflected pulse and the transmitted pulse. It is calculated
as:
where:
V
O
is the amplitude of the transmitted pulse, and
V
R
is the amplitude of the reflected pulse
A severe fault causes a large reflection, making V
R
relatively high. The dBRL value will therefore be low.
A minor fault produces a small reflection, making V
R
relatively low. The dBRL value in this case will
therefore be high.
In summary:
NOTE: the larger the dBRL reading, the smaller the problem and vice versa.
To display the dBRL of a discontinuity, move the cursor to its reflection. Continue to move the cursor
over the reflection until the dBRL reaches a minimum, which will usually be at its peak.
NOTE: the position of the cursor for dBRL measurements is different from its position for measuring the
distance to the discontinuity.