I remember as a kid seeing a structure similar to this one. I don’t remember exactly where, but it was somewhere along the route between Minneapolis and Duluth, with one horn facing south, and the other facing north. I asked my parents what it was, and they said it was for relaying TV signals. It made perfect sense to me, since the two horns looked a lot like TV screens.

I didn’t know what was inside, but now I do. The electronics were on the top floor, the B+ power supply was on the third floor, the filament power supply was on the second floor, and a backup generator was on the ground floor.

This diagram appeared 70 years ago this month in the February 1952 issue of Radio-Electronics.  Click on the image to see the full size version.