As a quick check, just go and do a poor man's setup and run long-ass RG6 or RG11 cable from the antenna to your TV. Then just start adding your pre-amps, etc. back into your setup one-by-one. If one piece of equipment kills everything, presumably that is what bad. If you add your pre-amp and your rotor, etc. all back and your signal kept, you know it was something with the existing coax in your system.
CM4228, CM4220HD, Samsung LNT3242H, AccessHD DTA1080D, RCA DTA800, CM7775, Samsung DTB-H260F, Samsung LN40B750