It requires a significant investment in equipment, an often pricey investment in real-estate, and the skills of a number of engineers. It's usually cheaper to buy an existing station that's struggling financially than to build a new one, but you will need a transmitter and the equipment to send content out via that transmitter. You may also need repeater stations in order to increase the range of your signal beyond the area your transmitter reaches. For each of these things, you must buy a piece of land and build a structure which houses your equipment. To do it legally, you must also obtain a broadcast license and any other permits you may need to operate in your area. You'll usually be required to follow a strict set of rules regarding content and code of conduct as well. If you wish to air a specific program, you'll need to pay for it. To pay for all that equipment and the programs you air, you'll need to sell advertisements and rely on them for most or all of your income. To make it simple, building a television station in the DTV era is equally as difficult as it was to build a television station 30 years ago. It's a very expensive endeavor, and it requires a great deal of planning too. In essence, however, it's simple electronics. You could research the term "pirate tv," and find out how it's moving into the DTV-era. Pirate TV is the concept of broadcasting television on an amateur and unlicensed basis. However, since it is quite illegal to broadcast in certain frequencies and above certain power levels without a license, I wont give you the gritty details here.