Glenayre Tsunami series, Installation And Maintenance Manual

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I N S T A L L A T I O N A N D M A I N T E N A N C E M A N U A L
T s u n a m i F A M I L Y
F A S T E T H E R N E T W I R E L E S S B R I D G E S
J U N E 1 9 9 9
SECTION 4: TROUBLESHOOTING PAGE 4-7
4.6.1 RF LINK Alarm
Function:
This LED indicates that the demodulator function is not synchronizing with the intended received
signal.
Possible Causes:
❖
Severe path fading due to atmospheric conditions, usually accompanied by low RSL
voltage reading
❖
Poor transmission line connections usually accompanied by low RSL voltage reading
❖
Antenna problems, misalignment, or path clearance usually accompanied by low RSL
voltage reading
❖
Improper radio settings (e.g. frequency channel)
❖
Received signal level (RSL) is too strong
❖
Interference
❖
Far-End radio transmitter circuitry is faulty
❖
Near-End radio receiver circuitry is faulty
Recommended Actions:
Check the following at each end of the link:
❖
Verify that rear panel filters are opposite channel plans on each end (e.g. one is A1 and
other is A2).
❖
Verify that rear panel DIP switch settings match each installed filter (see Section
3.12.1).
❖
Verify that all connections between radios and antennas are secure and all devices
between radios and antennas are rated for the radio frequency band (5.3/5.8 GHz).
Measure RSL by placing a voltmeter across RSL and GND test points. Compare this voltage to
the Factory Test Data Sheet and estimate the RSL in dBm. Compare this to the RSL that was
expected using path calculations (see Section 3.3.3). Press and hold the DISPLAY FAR END
button and measure the far-end RSL (while continuing to hold the button). Compare this RSL to
the Factory Test Data Sheet for the far-end radio and estimate the RSL in dBm. Again, compare
this RSL to the expected RSL from the link budget calculations.
If RSL from both ends of the radio are approximately the same as each other, but lower than
anticipated for this installation, then the likely cause of the BER alarm(s) is excessive losses
between the radios. Excessive loss problems could include the transmission line at either end, all
adapters, connectors, the antennas, the antenna alignment as well as the path itself (any
obstructions or clearance problems). Antenna alignment, line-of-sight and path clearance should
be verified; if this does not improve RSL, all devices between the radios and their antennas at
both ends should be checked. Make sure all transmission line, connectors and any other devices
are properly rated for operation at the radio's frequency (5.3/5.8 GHz).