Product and Software: This article applies to all Aruba controllers and ArubaOS versions.
If optimized coverage and rate-vs-range performance are not critical, you may decide to use only two antennas. However, consider these things:
- Make sure that the two antennas are connected to radio chains 0 and 1. Make sure that (two spatial stream) MIMO is still operational. The third chain only adds robustness and more uniform coverage, but it does not increase the maximum throughput.
- The third radio chain corresponds with a different antenna connector for 2.4 GHz and 5 GHz. If support for both bands and maximum two spatial stream MIMO rates are both needed, you need three antennas. If dual-band support is not needed, you can use only two antennas and still get the maximum two spatial stream data rate (300 Mb/s).
- For 2.4 GHz, the third chain corresponds with the bottom-left antenna connector (looking at the front of the AP, Ethernet connectors facing down). For 5 GHz, it is the top-left connector.
- If you want to support both bands, but do not need the two spatial stream MIMO rates, you could connect antennas to radio chain 0 only. This configuration is antenna connector top-left (2.4 GHz) and top-right (5 GHz). In this case, you should disable all MIMO rates (MCS8-15). This configuration basically gives you two single stream 11n radios, each their own (single) antenna. Though this is a valid option, it is not a good use of this AP.