Sports wagering has invigorated station groups’ core revenue, climbing to the second-biggest ad sales category for many of them and angling to knock automotive from its top spot in the next few years. Note: This story is available to TVNewsCheck Premium members only. If you would like to upgrade your free TVNewsCheck membership to Premium now, you can visit your Member Home Page, available when you log in at the very top right corner of the site or in the Stay Connected Box that appears in the right column of virtually every page on the site. If you don’t see Member Home, you will need to click Log In or Subscribe.