ThinkGood,
You're on to it!. [Linked Image]
Like Paul said, most people don't understand that RF amplifiers amplify EVERYTHING that is fed into them, noise included.
All a masthead-type amp, does, is maintains the signal at a given level, to remove some of the loss in the downlead, a bit like having your TV on the roof!. [Linked Image]
Customers that I've spoken to in the past, seem to think that an amp will make up for a poor Terrestrial signal or a shoddy installation job and man have I had some funny looks when I have told them the truth!.