I installed two Uda-Yagi antennas, spaced 0.5 m from each other, top is V-pol, bottom is H-pol in a hard NLOS position to the serving cell. The top aerial is 1850 MHz-optimised, the bottom is 1750 MHz-optimised.
Current performance indicators are:
RSRP: —98 dBm, RSRQ: —11 dB, SINR: —0.1 dB.
I cannot decide how to connect the aerials. Currently 1850 MHz-optimised aerial is connected to TX/RX port, and the 1750 MHz-optimised is connected to RX-only port, which gives me better Downlink speeds. But when I switch the ports vice-versa, I've got better Uplink speeds and less latency.
So, the MIMO is definitely works, but the effect is not dramatic (marginal performance difference).