Now I look again at the photo, there are two spirals, one which goes all the way to the outer edge of the dish, and another which only goes about on third of the way out.
If you look carefully at the centre of the dish you will see what appears to be a black "wire" coming from under the silver sticky tape. These two wires (the heater cable) appear to join together and then one cable, presumably the power feed, drops vertically from the centre of the dish and is then tywrapped on to the support structure.
JimB