The modem seems to support LTE CAT11 MIMO 4x4 with software options to use either;
- both sets of internal antennas (INT1 & INT2),
- or 2x external antennas via 2x TS-9/CRC9 ports (EXT1 & EXT2),
- or one of each (EXT1 & INT2).
I tested a cheap MIMO antenna (2x connector) which did provide a fair increase in speeds (& noise) however as I need one with longer cables I took it apart and it looks pretty basic inside:
However before I purchase another antenna I'm interested to know what is recommended price vs performance wise and whether it's better going with a single enclosed MIMO antenna (with 2x connectors) or two different antennas spaced apart?