What's this 20 50 and 62 stuff?
Young whippershnappers!
I have to laugh also - because my dad, who was a big electronic gadget guy, was still too cheap to ever spend much on a television, so my formative memories are 2,4,7,9 on an already ancient B&W RCA with a turner whose knob you had to jiggle all the time to hold a signal, and 56 at school - where we had some rooms wired to a central UHF antenna/RFamp system.
Of course since you can find anything on the net - this would be about the exact model!