High All,
I found a 1953 Zenith video at the Internet Archive advertising their 'turret tuner.' The video is entitled Fog Over Portland. It's 18 minutes long, free, and downloadable. It describes how Zenith's are superior in picking up UHF to the competitors. There is a shot of a porthole set. Thought you might enjoy a look-see.( https://archive.org/details/6407FogOverPortland01214405 )
Tinker