The customer that asked this has a HUAWEI B818-263 Router which is a 4×4 MIMO router with 2 external antenna connectors. He is worried that connecting a 2×2 MIMO Antenna to the router will give worse performance than not connecting any antenna.
The B818-263 router unfortunately only has 2×2 MIMO external ports. It is not obvious how the router will respond to the external antennas (maybe they have information in their user manual), but it is possible when connecting the two external ports that the 4×4 MIMO is downgraded to 2×2 MIMO, but it is also possible that they continue to use 4×4 MIMO with two internal antennas and two external antennas.
Connecting an external antenna allows much better signal reception, and more relevantly; better Carrier Signal to Noise Ratio (SNR), thereby improving the overall experience, even if only using 2×2 MIMO. The improvement in internet experience from having a good external antenna on this type of router usually outweighs the benefit of 4×4 MIMO. Peak throughputs may be better with 4×4 MIMO vs 2×2 MIMO, but the overall stability of the connection and overall experience should be much better with the implementation of an external antenna, e.g. our XPOL-2-5G antenna. You are welcome to have a look at our webinar titled: “Taking Fixed Wireless Access (FWA) from bits to Bytes” which has a section covering external antenna benefits.
If the router does support 4×4 MIMO with two internal router antennas and two external antennas, then the use of an external antenna will be even more beneficial.