Tennischannel.com/activate is a website where you can activate your subscription to the Tennis Channel. To activate, you will need to have a subscription to Tennis Channel through a participating cable or streaming provider. Once you have a subscription, you can go to tennischannel.com/activate and enter the activation code provided by your provider. This will activate your access to the Tennis Channel and allow you to watch live and on-demand matches. The activation process may vary depending on your device, but the website should provide detailed instructions for activation on various platforms such as Roku, Firestick, and Apple TV.