User's Manual

Exalt Installation and Management Guide
ExtendAir G2 24GHz Digital Microwave Radios
209866-002 77
2015-09-09
Changes in frequency, bandwidth, antenna polarization, or antenna position may remedy an
interference issue. However, if the system is licensed, these changes may not be allowed without re-
licensing.
Path Obstruction
A path obstruction is defined as an object, such as a building or tree, impeding the proper path of the
radio system. If the system design was proper at the time of installation and issues arise at a later date,
an updated path profile and survey may be necessary to identify changes in path clearance.
Misaligned Antenna
At the time of initial installation, it is critical that the antennas at each end are properly aligned and that
the designed RSL is achieved. However, antennas may become misaligned due to high winds, changes
in the guy-wiring systems keeping the antenna mast stable, or loosening of the antenna mounting
hardware. A reduction in the RSL of the link is symptomatic of this condition, but this condition is not
the only condition that results in a reduction of RSL. However, if conditions occur where the antenna
alignment may be suspected, the mechanics must be inspected and the antennas realigned.
Faulty Antenna
A faulty antenna is rare, but is still a possibility. In some cases, the mechanics of the antenna feed can
get moisture inside, or a bad or weak connection in the pin and connector structure of the antenna may
occur. A VSWR measurement of the antenna connection can be made to verify this condition.
Improper Grounding
In addition to being a potential human safety issue, improper system grounding can cause continuous
bit errors or bit errors when metal objects come in contact with the radio, transmission system, or
racking system. If touching the radio causes errors, check the ground connection. Grounding problems
can be difficult to diagnose, but a professional electrician can inspect a system and identify grounding
deficiencies.
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