WLAN Troubleshooting
Antenna cable

The type of cable shown in Figure that connects antennas to WLAN devices is a possible source of radio communication difficulties.

Cable selection is also important. When setting up bridges to communicate over a long distance, the antenna cables should not be longer than necessary. This is important because the longer a cable is, the more its signal will be attenuated, resulting in lower signal strength and consequently lower range. A Cisco bridge range calculation utility can be used to calculate the maximum distance that two bridges can communicate over based on the antenna and cable combinations in use.

Like any other network cables, the antenna cables must be properly installed to ensure that the signal they carry is clean and free from interference. To ensure that cables perform to their specifications, it is important to avoid the following:

  • Loose connections – Loose connectors on either end of the cable result in poor electrical contact and degrade the signal quality.
  • Damaged cables – Antenna cables with obvious physical damage do not perform to specification. For example, damage can result in induced reflection of the signal within the cable.
  • Cable runs shared with power cables – It is possible for EMI produced by power cables to affect the signal on the antenna cable.
  • Water in cable connections – It is possible for water to penetrate connectors that are not properly sealed. This will cause severe degradation to the RF signal.

For advanced troubleshooting a cable analyzer can be used to isolate problems.