Cisco 1601 Hardware Installation Guide - Page 188

Connecting an Antenna with the 3G Wireless WAN HWIC 3G Wireless WAN Interface Cards REVIEW DRAFT-CISCO CONFIDENTIAL Prerequisites for Connecting Antennas This section contains information about connecting the antennas. Note Before you connect the antennas, install the 3G wireless HWIC in the router. See Chapter , "Installing Cisco Interface Cards in Cisco Access Routers," for more information. In addition to antenna orientation, installation location with respect to other wireless equipment and other RF noise sources, such as telecom and datacom equipment, plays a significant role in determining overall network performance. Because antennas transmit and receive radio signals, their performance can be adversely affected by the surrounding environment, including distance between HWIC antenna and cellular base station, physical obstructions, or radio frequency (RF) interference. Follow these guidelines to ensure the best possible performance: • Wherever possible, mount the 3G wireless HWIC antenna away from physical obstructions. Barriers along the line of sight between HWIC antenna and cellular base station will degrade the wireless radio signals. The 3G wireless HWICs and antennas can be installed above floor level in office environments or near the ceiling for better performance because 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 signal degradation. - 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 a wire-mesh stucco wall causes signals to reflect back and causes 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 3G wireless 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. OL-12853-01 12