Can a broadcast methodology be marketed for profit and, if so, what legal protection is available (patent, copyright, etc.)?

My question is how can I approach a network with my broadcasting idea, yet still retain it's property as my own (at least) until I receive compensation (aka: sell the idea)? Initial research online seems to say that I cannot legally protect my idea as it is outside the scope of a copyright and doesn't seem to fall into the patent sphere either. Is it as simple as a "gentleman's correspondence" in which the company promises to pay for the idea if they like it? (that seems a bit risky in today's business climate).

Ultimately, I am unsure if my idea is tangible enough to be patented or copyrighted. It's not necessarily an entirely new way of broadcasting, but it is a marketable spin on entertainment. A similar example to my idea would be developing a specific, new way to film a movie. At the end, it is still a movie, but an industry change in how that movie is ultimately captured with existing technology, experienced, and subsequently enjoyed.