Safety Instructions For Antennas And Radios; Avoiding Damage To Radios In A Testing Environment - Cisco Aironet 1570 Series Installation Manual

Chapter 2 Preparing for Installation
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Safety Instructions for Antennas and Radios

In order to comply with radio frequency (RF) exposure limits, the antennas should be placed no less
Warning
than 50 cm (20") from your body or nearby persons. Statement 339
Do not locate the antenna near overhead power lines or other electric light or power circuits, or
Warning
where it can come into contact with such circuits. When installing the antenna, take extreme care
not to come into contact with such circuits, because they may cause serious injury or death. For
proper installation and grounding of the antenna, please refer to national and local codes (for
example, U.S.: NFPA 70, National Electric Code, Article 180, Canada: Canadian Electrical Code,
Section 54). Statement 1052
Warning Only trained and qualified personnel should be allowed to install, replace, or service this equipment.
Statement 1030

Avoiding Damage to Radios in a Testing Environment

The radios on outdoor units (bridges) have higher transmit power levels than radios on indoor units
(access points). When you test high-power radios in a link, you must avoid exceeding the maximum
receive input level for the receiver. At levels above the normal operating range, packet error rate (PER)
performance is degraded. At even higher levels, the receiver can be permanently damaged. To avoid
receiver damage and PER degradation, you can use one of the following techniques:
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Note
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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
OL-32138-01
If any part of the antenna system should come in contact with a power line, do not touch it or try to
remove it yourself. Call your local power company to have it removed safely.
If an accident should occur with the power lines, call for qualified emergency help immediately.
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.
These distances assume free space path loss and are conservative estimates. Required separation
distances for damage and performance degradation levels in actual deployments are less if
conditions are not non-line-of-sight
Reduce the configured transmit power to the minimum level.
Use directional antennas, and keep them away from each other.
Cable the radios together using a combination of attenuators, combiners, or splitters to achieve a
attenuation of at least 60 dB.
Cisco Aironet 1570 Series Outdoor Access Point Hardware Installation Guide
Safety Instructions for Antennas and Radios
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