Theirs actually a lot more variables then one would realize when you are dealing with a receive only situation, the two things that are constant for clear signal acquisition are line of sight/obstructions AND the antenna's height above ground. If your are on a second story of a house say and you have a clear line of sight to the transmitting tower you have a ton of advantages and it's not going to matter what length that antenna is, your going to reiceve the signal or not. Then again if your on the bottom side of an apartment complex with 20 miles and 2 large hills in between you and the tower, your going to have to add some things to achieve a better/best signal, once again it wont matter what length you put that antenna. Here's the trick I use - coat hanger in a loop and I can hear everything I want to hear...if I cant I need to start to think about exterior mounting and QUALITY coax runs AND their length/vs loss/signal acquisition.