The short answer to this question, without going into a lot of history and details, is that the frequencies once known as television channel one in the U. S. were reassigned by the FCC in the late 1940s-early fifties, but not necessarily to land-mobile radio services. These frequencies, again without going into details, eventually were reassigned to the Amateur Radio Service as the six-meter amateur band. If anyone here is a radio amateur operating six meters, and has a TV that still tunes channel 1 (many late-'40s Hallicrafters sets and possibly others of that era did), it shouldn't be too difficult to retune that channel's oscillator and antenna circuits to 50-54 MHz.
BTW, six-meter operation was probably not very prevalent in areas with a channel 2 TV station, due to the risk of interfering with reception of that station. The reason is that the low end of the frequency range of channel 2 is 54 MHz -- right at the top of the hams' 6-meter band. While most amateurs did not operate anywhere near that close to the edge of the band, some did, and therein lies the problem. If an amateur were operating, for example, on 53.8 MHz, lived in an area with a channel 2 TV station, and his neighbor was trying to watch a program on that channel, the latter would not be pleased when
"WB8XYZ calling WA8QRP, over" blasted through his TV speaker (along with interference to the picture), right over top of the program he was trying to watch.
I bet there was quite a bit of trouble like that in channel 2 areas in the early days of TV, immediately after the 6-meter band was opened to amateurs. I don't think there was much 6-meter activity in cities with channel 2 television stations for just that reason. This applies, of course, to television's beginnings in the late 1940s and very early fifties, when everything was on 12 channels, broadcast in monochrome and analog; NTSC color and UHF hadn't yet been thought of and the first TV systems in the U. S. were, of course, analog. The arrival of UHF in the late 1950s-'60s brought with it even more problems, not the least of which were weaker signals and a severe lack of sets that could receive the then-new UHF stations. Since most people living in areas with at least one UHF station still had VHF-only sets with UHF converters in those days, and the UHF stations themselves of that time weren't the high-power monsters they became by the '70s, the potential for interference was greater than before, not necessarily from 6-meter amateur signals but from hams' transmissions in other bands as well. Since UHF converters downconverted incoming UHF TV signals to an unused VHF channel, usually 5 or 6, a strong amateur signal appearing on either of these channels could cause real problems. Channel 5 is 76-82 MHz, six is 82-88 MHz, of course, but a very strong signal, amateur or otherwise, can blast its way past the tuner regardless of the channel's nominal frequency.
In the early 1970s, I lived in a Cleveland suburb which had an FM station on 92.3 MHz. I was living just one street over from that station's tower, and that station created very serious interference problems, not the least of which was to my TV, a 1964 Silvertone roundie, on which I could receive that station perfectly well (!) on channel 6. The problem was caused by the extreme signal strength in the area where I lived; it was just blasting its way through the set, with no regard for the tuned circuits in the tuner or anything else.
Hmmm.
I wonder if DTV is prone to the same kind of interference problems we had to tolerate in the NTSC analog era.