Bird Technologies SA-6000XT-Manual - Manual (Page 42)

26
Selecting Fault Location Mode
1. Press ON/OFF key for ½ second.
2. Press the MODE key.
3. Press the Fault Location softkey.
Figure 19 Select Fault Location Mode
Setting the Frequency Span and Max Distance
Note: Changing the frequency span or the max distance will auto-
matically turn calibration off. Always set the frequency span or max
distance before calibrating the unit.
The maximum distance measured is determined by the frequency span, the
velocity of propagation of the cable (V
p
), and the number of data points to mea-
sure (238, 475, or 949). These factors are discussed in the following paragraphs.
Max Distance -
When specifying a frequency span, the Site Analyzer calcu-
lates the maximum measurable distance. If the maximum distance being mea-
sured is known, it can be entered instead of the frequency span; the Site
Analyzer calculates the frequency span. If a maximum distance is manually
entered, select the data points before entering the max distance
Note: If a maximum distance less than the total length of the cable
system is selected, the trace might show a spike that is not really a
fault, but rather an echo from the portion of the cable that is beyond
the maximum length. Such a spike is known as an alias. To avoid
aliasing, always set the maximum distance to a value that is a few
feet or meters greater than the entire length of the cable system.