Before you purchase an antenna, you'll want to make sure your TV includes an integrated digital tuner. This is standard for virtually any TV you can currently buy, but if you still own a very old set you might need to purchase a separate digital tuner. You'll also want to check whether or not the antenna you're considering comes with a coaxial cord. The cord is the only way you can connect your antenna to your TV so you'll need to buy a separate one if it's not included. If you want to place your antenna in the window or in a space away from your TV, you should measure the distance beforehand to see if the cord is long enough.