User Manual

INSTALLATION AND MAINTENANCE MANUAL
LYNX.sc E1 FAMILY
SPREAD SPECTRUM RADIOS
OCTOBER 1998
SECTION 4: TROUBLESHOOTING PAGE 4-11
If one terminal (or both) has high RSL, this could be caused by a very short path or interference.
To verify the possible presence of interference, remove DC power to the radio which is opposite to
the one that is reading high RSL. Once power is removed, measure RSL on the remaining radio.
If RSL voltage is higher than that which is listed for "Threshold" in the Factory Test Data Sheet,
then an interfering signal is present. If interference is suspected, the easiest potential remedy is to
swap frequency channels on both sides of the link. See Section 4.2 for details. Swap frequencies
on both terminals so that they are the opposite from their original settings (e.g. change A1 into A2
and A2 into A1). Make sure that you change the DIP switch settings to correspond to the channel
change. After both ends are changed, reconnect the radios and determine if the BER alarm is still
active. If the BER alarm is still active, other frequency channels can be installed, or other
interference countermeasures can be tried, in accordance with Section 4.8.
If the BER alarm continues, an external BER test should be performed to verify the extent of bit
errors on the link. See Sections 4.9 and 4.10 for details on bit error rate testing. A BERT can be
connected on one side of the link, the External test mode selected on the near-end radio,
loopback enabled and bit errors evaluated. If the BER is above acceptable levels, continue to
troubleshoot the link.
If all path related and data input problems have been pursued and the BER alarm is still active,
the problem could be related to a radio failure. While radio failure is typically indicated by more
severe alarm conditions, it is possible that one of the radios may be out of specification, and this
could be the cause of the BER alarm. A back-to-back test will verify proper radio operation. See
Section 4.9 for details. A threshold test on both radios along with a test to verify proper RF output
power would be beneficial.
Perform a back-to-back test before returning any radio terminal to
the factory for repair. A back-to-back test verifies radio operation.
(See Section 4.9).
If the radios successfully pass their back-to-back testing, the problem is likely with the path or the
connections between the radio and the antenna or interference. Before reinstalling the radios, be
sure to set the output power to the appropriate level for the installation and set rear panel DIP
switches to the desired settings for the installation.