User's Manual

148 APCD-LM043-4.0
12 Troubleshooting
I
TIP Having a captive EUM at the CCU site can be helpful to isolate problems. With a
simple antenna, the captive EUM can be accessed from the CCU to confirm the
communications capability of the CCU, and the EUM can roughly verify the output
signal levels from the CCU.
If a captive EUM cannot be accessed, even
when set up in a high-signal receive area,
replace the CCU. If access is still not
possible, replace the CCU antenna system
with a “test antenna”, located 15’ or so from
the captive EUM, and repeat Tests G and H.
J
TIP If only EUMs with high signal levels (i.e., typically those close to the CCU) can be
accessed, suspect an interferer.
Go to
If You Have an Interferer on page 149.
K
Confirm CCU RF
network output power.
Check with other EUM
sites and confirm that the
receive signal level is per
the original installed
value.
Receive RF signal is per
original installed value.
CCU radio network
output is normal. Go to
Test P.
Go to Test L.
L
Verify RF network and
components.
Visually inspect all RF
connections.
Connectors look OK. Go to Test M. Repair connectors.
M
Use an RF sweep
generator test to look for
discontinuities in the RF
path.
No discontinuities
shown.
RF path looks OK. Go to
Test N.
RF path component is faulty. Repair/replace,
as appropriate.
N
Use a spectrum analyzer
to verify the RF system
and CCU output.
The CCU transmit power
at the CCU radio port
should be approximately
26dBm, using a
resolution bandwidth >
5MHz.
CCU output is OK. Go to
Test O.
Replace the CCU.
O
Measure the CCU
receive power with a test
antenna on the spectrum
analyzer. Adjust the
reading based on the
distance from the CCU
antenna.
RF path is OK. Go to
Test P.
Recheck RF path components.
P
Go to if you have an
interferer.
Table 35 Local Troubleshooting — CCU
What should I do? What is a good result?
What does a good
result mean?
What if I do not get a good result?