You don’t need a cable subscription to watch ABC, CBS or NBC – but don’t expect to learn about alternatives if you’re a Charter customer. Over-the-air antenna maker Antennas Direct recently wanted to buy some air time on Charter‘s cable channels to explain how TV viewers can access these channels without a pay TV subscription.

“We thought it was a fairly benign message,” Antennas Direct President Richard Schneider told me Thursday. Charter disagreed – and rejected the spot for competitive reasons.

The spot was part of a bigger marketing campaign that Antennas Direct is currently running for its products, with six different spots already airing in 15 markets and plans to show them in two dozen additional markets soon. Here’s one of them:

Antennas Direct has been one of a number of antenna manufacturers that has profited from interest in cord cutting. And over-the-air TV has also started to find its way into new technologies, including Boxee’s cloud DVR and Aereo’s TV streaming service. (Speaking of which: I’ll be interviewing Aereo founder and CEO Chet Kanojia at our paidContent Live conference in New York next month. Check out the full program for that event on the paidContent Live site.)

Schneider told me that the company’s early customers were mostly home theater enthusiasts interested in getting uncompressed HD TV signals. Then, some 18 months ago, more and more average consumers started to look for antennas – a trend that he largely attributes to the growing popularity of online streaming services. “Hulu and Netflix are helping revive antenna sales,” Schneider said, adding: “Over-the-air digital is really the new basic cable.”

Consumers would increasingly watch the basic broadcast channels for free, and then pay for catch-up and on-demand viewing, he argued. Of course, cable execs tend to argue that cord cutting doesn’t exist, even though people like Dish’s Charlie Ergen disagree. Asked about these arguments, Scneider responded: “Someone is buying all these antennas.”

Antennas Direct’s sales have nearly tripled last year, and the company is expecting to generate close to $15 million in revenue in 2013 – even without those ads on Charter.