I had an old small tv like that in my bedroom. There was a dial for vhf and another for UHF. The two UHF channels we had were about 20 and 31, but I found if I dialed it all the way to 90 or so sometimes I could hear voices talking to each other. Usually just boring phone calls, I showed my friends once and we listened to my friends uncle on a call by chance, he recognised the voice and the people he was talking about.

Then they switched mobile phones to a digital signal.