Several random points about UHF. Commercial antennas are not very expensive, and while anything NEAR the proper length will receive local stuff, there is some real technology in getting "gain" across the entire UHF band. "Gain" means receiving better than a plain old dipole (rabbit ears) in one direction, at the expense of the other directions. There is no free lunch in the antenna business, you can't have "gain" in all directions, the trick is to give up response in directions you don't need (like straight up) in return for better response along the horizion, for example. It's called "pattern" in the trade. Don't skimp on feedline, cheap coax is like a leaky pipe. A preamp at the antenna sees a better signal than anything downstream ( loss in the coax degrades the signal) and is a good idea unless you have a strong local signal to deal with. Inexpensive preamps designed for weak siignal work get "blown away" in an environment where a half a megawatt local is a few miles away, they can't deal with the strong local and still amplify the distant distant station you want..it's like trying to hear a whisper across the room when someone is yelling in your ear. An antenna with a sharp pattern (good 'front to back') will often allow you to "null" a local signal by turning it and allow reception of a weak one (null steering). Often with UHF there is a hot spot on a roof, commercial installers will often take a meter up
to the roof and walk around looking for it. THere's more, but the foregoing is a start.
