Cisco Cisco Aironet 1552WU Outdoor Access Point Guide De Montage

To avoid receiver damage and PER degradation, you can use one of the following techniques:

Separate the omnidirectional antennas by at least 2 ft (0.6 m) to avoid receiver damage or by at 
least 25 ft (7.6 m) to avoid PER degradation.

Reduce the configured transmit power to the minimum level.

Cable the radios together using a combination of attenuators, combiners, or splitters to achieve a 
total attenuation of at least 60 dB.

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

txpwr + tx antenna gain + rx ant 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 RF Attenuator components] < max rx input level 

(0 dbm)

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.