@Angela Cole yeah this is a really solid use case for directional antennas and your instinct is right — for a fixed base station talking to a remote sensor node, a Yagi or panel on the base side is probably the cleanest way to extend your link budget without touching the firmware or power settings at all.
The RF front-end on the MultiNav Pro+ is built around the STM32WB07 with external PA and LNA stages, and the antenna connection is a standard U.FL connector, so swapping to an external high-gain antenna is straightforward on the hardware side. The limiting factor you want to think about is your regulatory environment — in most regions you can't just pile on antenna gain indefinitely without bumping into EIRP limits, so check what your local rules allow before going too wild with a high-gain Yagi. That said, for a point-to-point field deployment like yours, even a modest 6-9 dBi panel on the base station side can make a meaningful difference, especially if you can elevate it and get clean line of sight.
One practical thing worth doing: put the directional antenna only on the base station side and leave the remote sensor node with the stock omnidirectional setup. That way the node can be deployed in any orientation without you worrying about alignment, and the base is doing all the "aiming." The link is reciprocal so the gain works both ways on the link budget regardless of which end it's on.
If you haven't already, pull the GitHub repo and look at the transmit power configuration options — there may be some headroom there too depending on what your current settings are.
