So supposedly such a center pivot is then 1/4 mile long. Wouldn't that then be a center pivot that's 1320' long? I think they're using a smaller setup here, but they're not exactly clear about that.

Edit: searching around, that sounds like a 10 tower. The article said they've got a 7. So I think they've got a lot more than I initially guessed and slightly less than your post guessed.