Smithsonian doesn't offer a live stream, only on-demand content. Therefore it is not able to be integrated into Channels.
Only networks which offer live streams of linear programming on their websites using TV Everywhere credentials are able to be used with Channels. If you know of a network that works for you in this manner that is not available in Channels, please contact the developers with the website where the live stream can be viewed so they may investigate whether it can be integrated.
