Exalt Installation and Management Guide
EX-r Series GigE Digital Microwave Radios
88
201872-003
2015-10-23
contact with the radio, transmission system, or racking system. If touching the radio causes errors,
grounding is the cause. It can be difficult to identify grounding problems, but a professional electrician
can normally inspect a system and identify if there are deficiencies in the grounding system.
Insufficient Link Margin
Ideally, the link was designed with enough link margin (fade margin) to allow for multipath
propagation and atmospheric fading and still remain reliable. In some cases, link margin is
compromised by economic factors, such as using low-cost RF cabling or lower-cost antennas that have
less gain or deficient performance compared to higher cost transmission system components. In some
cases, there may be antenna size restrictions that forced the design to not have the desired amount of
link margin.
If the link was designed with poor link margin, there are likely many cases of bit errors and outages.
The antenna system and transmission line can be upgraded to help reduce this. If the link design was
installed with sufficient margin, but RSL is reduced, the remaining link margin may no longer be
enough to maintain a reliable link. The causes of RSL reduction were previously described, but are
usually due to new path obstruction(s) or antenna misalignment due to wind or mechanical factors. The
antenna height or location can be changed to overcome new obstructions. Realignment of the antenna,
and/or improvement to mechanical structures can help overcome antenna misalignment.
Moisture in the Transmission System
If the connectors on cables and antennas and egress junctions are not properly weatherproofed,
moisture can get into the transmission system and cause significant error conditions and erratic
performance. In many cases, the transmission system must be replaced. A VSWR meter is one means
to identify such issues. Conduct physical inspections often. If changes to the weatherproofing (such as
cracking) are noticed, replace the weatherproofing before leakage occurs.
