When I started my practicals I was working with the NanoStation 2, a very old model from the Ubiquiti line of products. It was possible on these devices to connect an antenna.
It is no longer possible to mount antennae on any of the Nanostation models.
We soldered pigtail cables on a Nanostation Loco M2 device and it did not help to boost the signal, matter of fact signal quality dropped a tiny bit, these devices cannot power up such antennae. The For external antennae connectivity consider getting Ubiquiti Rockets instead.