I am installing the Intel Dual Band Wireless-AC 8265 desktop kit in a Dell micro PC that only has room for one antenna. Our PC's connect via 5Ghz. The M.2 antenna card has connections for two antennas, labeled 1 and 2. Which one do I use for best 5Ghz results.
I would add the following to Wanner's recommendations. The AC 8265 WiFi adapter is designed for the MAIN (2) antenna to handle WiFi communication and the AUX (1) antenna to handle both WiFi + Bluetooth. Since BT uses 2.4 GHz band, the 5GHz antenna should be connected to the MAIN (2) connector.