This post has made me wonder what other pairings of VHF Band III channels couldn’t have been used in the same area for analog TV
VHF 6 & 7
VHF 7 & 8
VHF 8 & 9
VHF 6 & 9 ??
VHF 6 & 10 (as above)
VHF 7 & 11 ??
Are the reasons that some are too close together (though noting 9 and 10 can be used together) or oscillator IF or something else?