It is one of popular culture’s generational divides: whether you are old enough to remember when television stations concluded the night’s programming with “The Star-Spangled Banner.” Decades ago, viewers would see a slide show of American imagery, perhaps a mountain range or frothy shoreline and then — hours of static .

Now, the early morning hours are filled with rebroadcasts and infomercials, eliminating any practical reason for a formal sign off.

But recently, television broadcasters have been reintroducing the practice of playing the national anthem once a day, pairing it with the same flavor of patriotic imagery, but in high definition and with multilayered audio. Some viewers might hear political overtones, too.

Gray Television, which has 145 stations, mostly in small and midsize markets, made it a companywide practice several months ago. Two other companies followed: CBS, at its 27 corporate-owned stations, including those in New York and Los Angeles; and Nexstar Media Group, one of the largest owners of television stations in the country. Within five months, the national anthem has become a daily part of programming at more than 350 stations across the country.