Case Study: STAs Encounter Weak Signals or No Signals in the Coverage Area Due to Incorrect Antenna Selection
Symptom
An AP works properly, but the signal strength in the coverage area is still weak or even no signal is available.
Relevant Alarms and Logs
None
Cause Analysis
- At a carrier site outside China, outdoor APs with omnidirectional antennas are deployed on the rooftop of a building to provide wireless network coverage for the whole building. After the uplink RSSI of STAs is checked, it is found that the signal strength is weak at the lower-floor areas of the building.
- At a higher education site in China, a 5 GHz antenna is installed on the 2.4 GHz radio port of an outdoor AP. When a channel scanning tool is used to detect signals, no 2.4 GHz signal transmitted by this AP is detected.
If improper antennas are selected, signal strength in the coverage area is weak or even no signal is available.
Procedure
- To provide long-distance coverage, use directional small-angle antennas for outdoor APs, instead of omnidirectional antennas.
- Replace the 5 GHz antenna on the 2.4 GHz radio port with a 2.4 GHz/5 GHz antenna.
Suggestion and Summary
Outdoor APs are usually installed at high positions, and the uplink backhaul distance of STAs cannot exceed 50 m. Therefore, directional small-angle antennas are generally used for signal coverage. For details about how to select antennas in different scenarios, see WLAN Antenna Quick Start.
A single-band or dual-band radio port is clearly identified on an outdoor AP. The antenna connected to a radio port must meet requirements of the radio port. If the frequency band of the selected antenna does not match that of the radio port, the AP cannot transmit radio signals.