JDS Uniphase OneExpert DSL, User Manual

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Chapter 7 Testing with SmartIDs
Coax Map test
OneExpert DSL User’s Guide
56
22052280, Revision 001 April 2014
Table 6 describes the Coax Map results.
Table 6 Coax Map results
Results Description Units Range/Values
Length Total length of the coax leg from test
instrument. ft. 0-500
dBrl Return loss of the coax leg. dBrl
Comment Description of the event that was
detected in the coax cable Unknown, Open, Splitter, Barrel/Splice,
Splitter *, and Low Quality Splitter (see
Table 7 for descriptions)
Table 7 Comment result descriptions
Label Description
Unknown This label is used as a last resort when no other signatures can be identified.
Open Indicates an event that has high return loss.
– A home run cable with no passive devices should indicate an open at close to 0 dBrl
– A cable with a 2-way splitter may have two opens at close to -7 dBrl.
– A cable with a 3-way splitter may have two opens at -14 dBrl and one open at -7 dBrl
Splitter Indicates a passive splitter may be present at this length in the cable under test.
Low Quality Splitter Indicates a low quality splitter may be present at this length. Low quality splitters can induce
standing waves and cause poor performance. These low quality splitters can also cause con-
ventional cable ID to function incorrectly since many are DC coupled causing the ID resistive
values to be placed in parallel.
Splitter * Indicates an assumed splitter. The instrument has not detected a splitter signature. However,
based on the data signature the instrument has deduced that a splitter is likely present.
NOTE: If the length to the splitter* and the first open are the same, it is likely a splitter with an
open port.
Barrel/Splice Indicates an event was detected followed by a single low loss open event. This can be caused
by barrel splices, Low Quality Splitter with an open port, severely kinked or crimped cable (Sta-
bles), poor connector, etc….
The return loss of the Barrel/Splice event should be considered when determining what action,
if any, is required. Lower return loss (around -20 dBrl) values may not require action, but high
values indicate an event that may be effecting cable performance.
NOTE:
In the unlikely event that the legs of a splitter are the same length, the instrument will report a
single event with a return loss value that approximately equals the sum of the events.