6100-Gfast Multifunction Copper Tester Operation Manual
© 2020 Radiodetection Ltd
73
that may otherwise be hidden with the normal
VF/AC
Balance
test.
The test is very similar to the classic
stress
test well
known in North America. Compared to the VF
(longitudinal) Balance test, values for the
Stressed
Balance
test are depicted as follows (but check your
own methods and procedures):
good < 20 dBRNc
marginal = 20 to 30 dBRNc
bad > 30 dBRNc
In general, a pair that
stresses
< 25 dBRNc is well
balanced for POTS and ADSL internet service.
However, higher speed ADSL2+ and VDSL2 circuits
should stress < 20. A low stress value (> 20) indicates
imbalance on the pair, which can have different causes.
Most common causes are grounds and shorts, but also
one-sided series resistance (sometimes also called
high-open, high-resistive fault, or
dirty open
). Poor or
failing splice connectors/beanies also case minor
imbalances affecting higher speed DSL circuits.
Watch the stress level, and if you see an increase or
jump after a minute or two or more, the stress may
have worked through some corrosion and thus
revealed an imbalance. However, if the stress improves
and you see a lower value after a minute or two, then
the stress voltage may have dried up some moisture,
thus hiding a wet/damp fault, which will appear again
when more moisture works its way back into the fault.
When you have a poor stress value (> 25), the next
best step is to isolate the imbalance by running the
Pair
Detective
test.
To access Pair Detective from Multimeter tests:
1. Press
to return to the
Copper Main
menu.
2. Highlight
Pair Detective
and press
to
launch the test.
3. Open the far end, and see that faults are
identified.
4. Check the
Pair Detective TDR
to locate
identified faults.
If corrosion is identified, it may be difficult to
locate with the
TDR
. To confirm, run the
Resistive Balance
test.
To access the Resistive Balance test:
1. Press
to return to the Multimeter menu.
2. Highlight
Resistive Balance
and press
to
launch the test.
It does first require a T-R-G/A-B-Earth short at
the far end. This will confirm if ohms on one
side are higher than the other and there is a
one-sided high-resistive fault. If the Ohms on
the faulted side measure < 20 M Ohms, use
the
RFL Single/Separate Good Pair
method
(depending on available spare pairs) to try to
locate the corrosion. See
more help on using this test.
The
Stressed Balance
parameters are as follows:
Current Group
is the current test group name,
for example
Multimeter
.
Current Test
displays the test being
measured. Here you can switch to another
Multimeter
test from the given list. However,
this action will terminate the ongoing
measurement test.
Noise Filter
is a fixed value set to
C-message
.
Termination Resistance
is a read-only value
of
600 Ω
.
