This HAT product is a major step forward for amateur radio operators integrating Raspberry Pi with digital applications. You can read Julian’s (OH8STN) blog on this product. If you don’t follow Julian, I suggest you do. Julian specializes in portable, digital operation in the field.
From John, K5ACL
From Julian, OH8STN.
From Ashhar Farhan, VU2ESE. For more info, check the following links. Hackaday article.