User's Manual
Table Of Contents
- Contents
- Important Information
- Notices
- Description
- Installation
- Configuration
- Overview
- Accessing the Main Menu
- Configuring with the Main Menu
- Unit Identification
- Hardware/Software Revision
- System Software ROM Images
- System Current Status
- Network Configuration
- IP Filter Configuration
- RF Station Configuration
- Viewing Current RF Station Configuration
- Setting the Operating Mode
- General Equipment Setup for Performing RF Tests
- Setting Test Mode Timer Minutes
- Performing Link Monitor Test (Normal Mode)
- Performing Transmit and Receive Tests
- Performing the RSSI Test
- Setting the RF Transmit Status
- Setting the Link Monitor Period
- Setting Maximum Remote Distance (Base Station Only)
- Setting Link Monitor Remote Station Rank
- Adjusting Throttling (Remote Station Only)
- Setting Tx Power Automatically (Remote Station Only)
- Adjusting User Output Power Ceiling (Remote Station Only)
- Setting Signal Margin (Remote Station Only)
- Viewing Current Output Power Level Adjust
- Radio Module Configuration
- Viewing the Radio Module Configuration
- Setting Config Test Minutes
- Setting the Station Type
- Setting the Station Rank
- Setting the Center Frequency
- Setting Security Passwords
- Setting the Scrambling Code
- Setting the Acquisition Code
- Adjusting the Tx Power Level
- Setting a Base to Repeater Mode (Base Station Only)
- Setting System Symmetry Type (Base Station Only)
- Setting Dynamic Polling Level (Base Station Only)
- Setting Remote Unit RF Group
- Rebooting and Saving RF Module Configurations
- RF/Ethernet Statistics
- System Security
- System Commands
- Link Monitor Display
- Logout
- Setting Operating Mode with the Mode Button
- Command Line Interface
- Troubleshooting
- Appendix A: Planning Your Wireless Link
- Appendix B: Using HyperTerminal
- Appendix C: Configuring a Simple Data Network
- Appendix D: SNMP
- Appendix E: Technical Reference Information
- Appendix F: Menu Map
- Appendix G: Upgrading Software
- Glossary
- Index
Appendix A: Planning Your Wireless Link
116 AWE 120-24 Installation & Configuration Guide
Each variable is described below.
System Gain
The system gain of a radio system is the difference between the transmitted power and a receiver’s sensitivity
threshold. The system gain of the AWE 120-24 is calculated as follows.
To ensure reliable communications, the system gain plus all antenna gains must be greater than the sum of all
losses. For a reliable link, Wi-LAN recommends that the system gain plus all antenna gains be greater than the
sum of all losses by 15 dB. This amount is the fade margin.
EIRP (Effective Isotropically Radiated Power)
EIRP is the power that radiates from an antenna, taking into account the output power from the transmitter,
the connector and cable losses, and the antenna gain. Unlike the Tx output power of the devices, EIRP takes
account of antenna gain and cable losses. Antennas use directional gain to increase the effective radiated
power. Losses such as cable losses reduce the effective radiated power.
You calculate the EIRP as follows.
Fresnel Radius Distance around line-of-sight that must be clear of obstacles
Cable Loss Signal loss experienced as it passes through the coaxial cable, expressed in dB
Path Loss Total loss from one end of the path to the other. Includes propagation losses,
cable losses and any other losses that impact the system performance
Formula:
System Gain = Transmission Power - Receiver Sensitivity @ 10
-6
BER
Variables: Tx Power = 20 dBm
Receiver Sensitivity = –81 dBm (receiver sensitivity @ 10
-6
BER)
Calculation: 20dBm – (–81) dBm = 101 dB
Formula: EIRP = Tx Power (dBm) - Cable Losses (dB) - Connector Losses (dB) + Antenna Gain (dBi)
Note: The FCC regulatory body has set the EIRP limit to +36 dBm for point-to-multipoint
applications per FCC 15.247(b)(3)(i).
For point-to-point applications, the FCC EIRP can be 3 dB higher than +36 dBm for every
1 dB less Tx power below 30 dBm.
Industry Canada specifies the EIRP limit to ≤+36 dBm for point-to-multipoint as per
RSS-139 Annex B.
In accordance with ETS 300-328 for 2.4 GHz RLANs, the maximum EIRP shall not exceed
+20 dBm, with a maximum SPD (Spectral Power Density) not exceeding +10 dBm/MHz.
Confirmation is required with the relevant European national radio communications local
authority for deviations from this specification.
Variable Description