3Com 3CRWE80096A User Guide - Page 17

Selecting A Different Antenna 11 Selecting A Different Antenna The standard detachable portable antenna supplied with the access point is a multi-purpose antenna suitable for a variety of environments, including office LANs, physical plants, and factory floors. If your site has special requirements that might be served by different types of antenna, four optional antenna models are available, as shown below: Model number 3CWE490 3CWE492 3CWE497 3CWE498 Design and type Omnidirectional (fiberglass) Ceiling-mount omnidirectional Ceiling-mount hallway Directional Panel (indoor/outdoor) Frequency Range 2.400-2.4835 GHz 2300-2500 Mhz 2300-2500 Mhz 2300-2500 Mhz Gain 4 dBi 2.5 dBi 4 dBi 8 dBi VSWR across band < 1.5:1 < 1.35:1 < 1.5:1 < 1.5:1 Distance (coverage)* 2100 feet 1800 feet 2100 feet 3600 feet Effective Radiated Power High: 159 mW (ERP) @ different power Medium: 50 mW transmission settings** Low: 13 mW High: 112 mW Medium: 36 mW Low: 9 mW High: 159 mW Medium: 50 mW Low: 13 mW High: 398 mW Medium: 126 mW Low: 32 mW Temperature range -40°C to +80°C -40°C to +80°C -40°C to +71°C -40°C to +80°C Dimensions (inches) 10" (height) 4.25 (diameter) 2.6 x 1.8 x 0.2 5.1 x 4.7 x 1.5 Weight 5.34 oz. 8 oz. 2 oz. 8 oz. Cable A six-foot accessory cable (model 3CWE480) is required for each of these optional antennas. It provides the transition from the SMA connector on the access point to the N-type connector on the antenna. A 20-foot cable (model 3CWE481) is also available. * Coverage varies depending on building construction. ** See "Setting Data Transmission Properties" on page 27 for information on selecting power transmission levels. You can order any of the optional antennas by model number from the 3Com Web site. Omnidirectional Antenna The fiberglass omnidirectional antenna (model number 3CWE490) is designed for use in harsh indoor environments. It can be centrally located on the ceiling to provide uniform coverage over a wide area. This antenna features a built-in matching network that eliminates the need for a ground plane. This antenna can be mounted on the ceiling by means of a standard ceiling-mount bracket. Before installing, ensure that access is available for cable routing. This antenna does not have an electrical connection between the mask mount and the coaxial cable shield. However, adding a lightning arrestor will correct this situation by grounding the outer shield as recommended. Some arrestor designs provide over-voltage protection for the signal sent down the cable. If you use such