Cisco AIR-BR1410A-A-K9 - Aironet 1410 Wireless Bridge Deployment Manual page 33

perform an interference analysis using a spectrum analyzer to make sure you have an interference
free radio link. It may also be necessary to do a link budget for the link to assure feasibility before
implementation and to know expected receive signal level before alignment of antennas to optimize
the link.
Any of the following frequencies bands may, at any time, contain high-power pulsed signals, either
ground-based or mobile. These high power signals (if in close proximity) may degrade the 1400
series receiver causing performance issues.
4.990-5.000 Meteorological - radio astronomy
5.250-5.650 Radio location (coastal radar)
5.460-5.470 Radio navigation - General
5.470-5.650 Maritime radio navigation
5.600-5.650 Meteorological - Ground based radar
Licensed Radio Amateurs (Ham Radio) utilize the 5.650-5.925 GHz on a shared basis with all the
above users on a secondary, non-interference basis. There are a few full-time (on the air
continually) point-to-point amateur radio microwave links that may operate in this band. These links
can be anywhere in this frequency range and are typically low power using high gain dish antennas.
Other Radio Amateur usage tends to be intermittent with usage clustered around 5760 MHz.
There are a few high-power users of this band doing moon-bounce and troposcatter
communications but again, this tends to be intermittent.
The Radio Location band from 5.250 to 5.650 GHz is shared with "Radiolocation" or radar, of
which the most active user is AWACS. Although the frequency band falls in UNII-1 & UNII-2
band range (5.150-5.350 GHz), the first and second harmonic (weaker signals) may be present in
UNII-3 band, but this airborne platform has many-megawatt ERP pulsed signal source and can
appear anytime there is an active AWACS aircraft aloft. So this could affect your wireless bridge
links should these links fall in the main beam of the radar.
Currently, there are a large number of C-band (3.7-4.2 GHz) receive-only satellite users that are
experiencing tremendous interference problems with this radar saturating their LNAs when it is in
the area. Although C-band is a bit more far away from the radio location band as compared to
UNII-3 band, since some users of C- Band have experienced some interference issues believed to
be caused by AWACS usage, it is possible that the 1400 Series Bridge links may encounter some
interference when located around and near airports.
5.2 Embedded features in 1400 series wireless bridge to fight against
interference
The 1400 Series Wireless Bridge has many features to fight for interference. To assist in resolving
interference issues, one can conduct a search for least congested channel, which is an inbuilt feature
in the bridge. Another important feature within the 1400 Series Wireless Bridge is Programmable
Clear Channel Assessment (CCA). CCA threshold can be used to decrease the receiver sensitivity
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