It’s not common to see a dish installation on roof top in Japan. They are most likely on one side of the way or out side of balcony guard railings. Most dishes are installed using brackets, not through drilling screws.
The bracket was mounted by screws, rusted already but the installation is very strong. I was there for 4 years already, I asked the house owner, a shop office actually.
In some cases, wherever there’s no exsiting railings to mount dishes, they have to be mounted on side wall, like this one:
The stand arm are not curve ones, most of them are right angel, so the dishes do not look sticking out. I like this design.
Twin panel type UHF antenna for terrestrial digital broadcasting. Not looking like any traditional UHF aerial. It could be easily mounted on any type of guard railings. There are 3 colors to choose. Most commonly found ones in Japan are in brown color, to match the house color.