Cisco Cisco 2.4-GHz Swivel-Mount Dipole Antenna 23.7786.51 - Manual (Page 7)

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Cisco 2.4-GHz Swivel-Mount Dipole Antenna (23.7786.51)
OL-7701-01
Installation Notes
Because antennas transmit and receive radio signals, their performance can be adversely affected by the
surrounding environment including distance between access point and client, physical obstructions, or
radio frequency (RF) interference.
Follow these guidelines to ensure the best possible performance:
• Wherever possible, mount the AP HWIC and antenna where the wireless devices would be within
sight and avoid physical obstructions. Barriers along the line of sight between client and access point
will degrade the wireless radio signals. AP HWICs and antennas can be installed above floor level
in office environments or near the ceiling for better performance since most obstructions tend to be
near floor level.
• The density of the materials used in a building's construction determines the number of walls the
signal must pass through and still maintain adequate coverage. Consider the following before
choosing the location to install your antenna:
– Paper and vinyl walls have very little effect on signal penetration.
– Solid and precast concrete walls limit signal penetration to one or two walls without degrading
coverage.
– Concrete and wood block walls limit signal penetration to three or four walls.
– A signal can penetrate five or six walls constructed of drywall or wood.
– A thick metal wall or wire-mesh stucco walls causes signals to reflect back and cause poor
penetration.
• Avoid mounting the antenna next to a column or vertical support that could create a shadow zone
and reduce the coverage area.
• Keep the antenna away from reflective metal objects such as heating and air-conditioning ducts,
large ceiling trusses, building superstructures, and major power cabling runs. If necessary, use an
extension cable to relocate the antenna away from these obstructions.
Caution Install the AP HWIC and any antennas away from appliances that share the same frequency bands.
Microwave ovens, cordless telephones, and security monitors can temporarily interfere with wireless
performance.
Caution We recommend you avoid installing wireless antennas in or near rack-mounted installations that include
networking equipment and computer servers whose radiated noise emissions can severely degrade radio
performance.
Note If the desired installation site has a marginally acceptable level of radiated noise emissions, consider
using a remote-mounted antenna, such as a wall-mount or ceiling-mount antenna, for better radio
performance and coverage.