Appendix B Wireless LANs
NWA-3500/NWA-3550 User’s Guide
345
Antenna Overview
An antenna couples RF signals onto air. A transmitter within a wireless device
sends an RF signal to the antenna, which propagates the signal through the air.
The antenna also operates in reverse by capturing RF signals from the air.
Positioning the antennas properly increases the range and coverage area of a
wireless LAN.
Antenna Characteristics
Frequency
An antenna in the frequency of 2.4GHz (IEEE 802.11b) or 5GHz(IEEE 802.11a) is
needed to communicate efficiently in a wireless LAN.
Radiation Pattern
A radiation pattern is a diagram that allows you to visualize the shape of the
antenna’s coverage area.
Antenna Gain
Antenna gain, measured in dB (decibel), is the increase in coverage within the RF
beam width. Higher antenna gain improves the range of the signal for better
communications.
For an indoor site, each 1 dB increase in antenna gain results in a range increase
of approximately 2.5%. For an unobstructed outdoor site, each 1dB increase in
gain results in a range increase of approximately 5%. Actual results may vary
depending on the network environment.
Antenna gain is sometimes specified in dBi, which is how much the antenna
increases the signal power compared to using an isotropic antenna. An isotropic
antenna is a theoretical perfect antenna that sends out radio signals equally well
in all directions. dBi represents the true gain that the antenna provides.
Types of Antennas for WLAN
There are two types of antennas used for wireless LAN applications.
Summary of Contents for NWA-3550
Page 2: ......
Page 8: ...Safety Warnings NWA 3500 NWA 3550 User s Guide 8...
Page 10: ...Contents Overview NWA 3500 NWA 3550 User s Guide 10...
Page 20: ...Table of Contents NWA 3500 NWA 3550 User s Guide 20...
Page 22: ...22...
Page 40: ...Chapter 2 The Web Configurator NWA 3500 NWA 3550 User s Guide 40...
Page 80: ...Chapter 3 Tutorial NWA 3500 NWA 3550 User s Guide 80...
Page 82: ...82...
Page 92: ...Chapter 5 Management Mode NWA 3500 NWA 3550 User s Guide 92...
Page 108: ...Chapter 6 AP Controller Mode NWA 3500 NWA 3550 User s Guide 108...
Page 144: ...Chapter 8 Wireless Configuration NWA 3500 NWA 3550 User s Guide 144...
Page 168: ...Chapter 10 Wireless Security Screen NWA 3500 NWA 3550 User s Guide 168...
Page 182: ...Chapter 13 MAC Filter Screen NWA 3500 NWA 3550 User s Guide 182...
Page 186: ...Chapter 14 IP Screen NWA 3500 NWA 3550 User s Guide 186...
Page 194: ...Chapter 15 Rogue AP Detection NWA 3500 NWA 3550 User s Guide 194...
Page 216: ...Chapter 17 Internal RADIUS Server NWA 3500 NWA 3550 User s Guide 216...
Page 244: ...Chapter 19 Log Screens NWA 3500 NWA 3550 User s Guide 244...
Page 270: ...Chapter 21 Load Balancing NWA 3160 Series User s Guide 270...
Page 274: ...Chapter 22 Dynamic Channel Selection NWA 3160 Series User s Guide 274...
Page 286: ...Chapter 23 Maintenance NWA 3500 NWA 3550 User s Guide 286...
Page 287: ...287 PART III Troubleshooting and Specifications Troubleshooting 289 Product Specifications 297...
Page 288: ...288...
Page 296: ...Chapter 24 Troubleshooting NWA 3500 NWA 3550 User s Guide 296...
Page 304: ...304...
Page 398: ...Appendix F Text File Based Auto Configuration NWA 3500 NWA 3550 User s Guide 398...