How do you align your TV aerial?

Club site pans are improving in detail and most, if not all, indicate the direction of North. It has always occurred to me that site plans ought, also, to show the direction of the local TV transmitter(s) and their orientation (vertical or horizontal). There’d be no point on those sites where a reception cannot be achieved, of course, but it’d save a lot of ‘faff’ for those wanting to set one up.

You could walk out to see which way others have pointed theirs but it’s surprising how often you find yourself surrounded by omni-directional aerials, satellite dishes, or other aerials that are not in use.