New Driver for Alfa AWUS1900 802.11ac USB adapter (also for AWUS036AC and AWUS036ACH)
In December 2017, Realtek released driver version 1030.25.701.2017 for Alfa AWUS1900. It was released in a Windows Update package so many of you may already be on this new driver if you have run Windows Update recently.
If you have not, then you can now directly download this driver package here. Once downloaded, open it and run the Setup.exe program inside.
Upon completion, you can check your Device Manager properties for this device (go to Device Manager > Network Adapters > right click this adapter and select Properties, then go to Driver tab) and make sure the driver date now shows 12/25/2017.
Adapters compatible with above driver update: