C i s c o C o n f i d e n t i a l - D r a f t 1
2-6
Cisco Aironet 1500 Series Outdoor Mesh Access Point Hardware Installation Guide
OL-9977-05
Chapter 2 Mounting Instructions
Installation Guidelines
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
Caution
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 PER performance is not degraded.
Installation Guidelines
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
Deployment Guide: Cisco Mesh Networking Solution.
•
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.
Note
Cisco recommends installing the access points no higher than 40 feet to allow support for wireless clients
on the ground.
Note
To calculate path loss and to determine how far apart to install access points, consult an RF planning
expert.
Site Surveys
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:
•
Data rates—Sensitivity and range are inversely proportional to data bit rates. The maximum radio
range is achieved at the lowest workable data rate. A decrease in receiver sensitivity occurs as the
radio data increases.
