@scully Ah ok, but you do have power in the barn? In such case I'd just go for a directional WiFi antenna (like Yagi) on both ends. No need to top class, 200 m is nothing unusual for WiFi bridges. On both ends you can use TP-Link or OpenWrt WiFi access points, even the cheap ones, you just need one in Access Point mode, the other in WiFi client mode. Chances are it would even worth with directional antenna on the house, but signal may be patchy during fog etc so when you need monitoring most.