Cisco Systems 1552H Benutzerhandbuch

For a radiated test bed, the following equation describes the relationships among transmit power, antenna 
gain, attenuation, and receiver sensitivity:

txpwr + tx gain + rx gain - [attenuation due to antenna spacing] < max rx input level

Where:

txpwr = Radio transmit power level

tx gain = transmitter antenna gain

rx gain = receiver antenna gain

For a conducted test bed, the following equation describes the relationships among transmit power, 
antenna gain, and receiver sensitivity:

txpwr - [attenuation due to coaxial components] < max rx input level

Under no circumstances should you connect the antenna port from one access point to the antenna port 
of another access point without using an RF attenuator. If you connect antenna ports, you must not 
exceed the maximum survivable receive level of 0 dBm. Never exceed 0 dBm, or damage to the access 
point can occur. Using attenuators, combiners, and splitters having a total of at least 60 dB of attenuation 
ensures that the receiver is not damaged and that PER performance is not degraded.

Because the access point is a radio device, it is susceptible to common causes of interference that can 
reduce throughput and range. Follow these basic guidelines to ensure the best possible performance:

For information on planning and initially configuring your Cisco Mesh network, refer to the Cisco 
Wireless Mesh Access Points, Design and Deployment Guide, Release 7.3.

Review the FCC guidelines for installing and operating outdoor wireless LAN devices at 

.

Perform a site survey before beginning the installation.

Install the access point in an area where structures, trees, or hills do not obstruct radio signals to and 
from the access point.

The access points can be installed at any height, but best throughput is achieved when all the access 
points are mounted at the same height. We recommend installing the access points no higher than 
40 feet to allow support for wireless clients on the ground.

To calculate path loss and to determine how far apart to install access points, consult an RF planning 
expert.

Every network application is a unique installation. Before installing multiple access points, you should 
perform a site survey to determine the optimum use of networking components and to maximize range, 
coverage, and network performance.

Consider the following operating and environmental conditions when performing a site survey: