Returning to the Holme Moss issue, of course it could have provided closely similar coverage for two VHF channels if both had been in Band I. Had the channel planning been done differently, without the initial (mis)use of Band III for non-broadcasting purposes, one could make the case that two Band I channels should have been allocated to Holme Moss, with perhaps some of the second-level transmitters moved from Band I to Band III for the 1st programme.
Holme Moss is somewhat analogous to Te Aroha here in NZ, although the latter is atop a mountain peak in rugged country. But neither is located in a major population area, but rather both broadcast to lower-lying populated areas either side of the divide upon which they were sited, in the Te Aroha case the Waikato, including Hamilton, to the west, and the Bay of Plenty, including Tauranga, to the east. Te Aroha was the only one of the seven main transmitters to use Band I for both channels, namely channel NZ1 for TV1 and channel NZ3 for TV2. The other six used a Band I channel for TV1 and a Band III channel for TV2. So when the channel allocations were made, the special needs of the Te Aroha transmitter, which had a larger footprint than the other main transmitters, were evidently taken into account. As I recall, second-level transmitters tended to use Band III channels for both TV1 and TV2.
Nonetheless, early BBC planning for two-programme national VHF TV coverage did include a Band III transmitter at Holme Moss, as shown in this excerpt from WW 1953 June. I imagine that the coverage from such a transmitter would have fallen noticeably short of that obtained with the channel B2 transmitter.
And the following shows that for its 1st programme, the BBC originally envisaged using two Band III channels for some of the second-level transmitters. But it had to rework these to use Band I channels, and so Band I ended up being over-subscribed.
Then this item suggests that co-siting and even co-masting of the ITA and BBC VHF transmitters was considered in the early days. The BBC had included provision for Band II FM radiators on its masts/towers from Sutton Coldfield onwards, and I think (not 100% sure) for Band III TV radiators from Pontop Pike onwards.
colly0410 wrote:I suppose we were the only Country that had channel out of sequence rotary VHF tuners, unless someone knows different..
I have never come across any information to suggest that non-sequential VHF tuners were used elsewhere, but that does mean that they were not. The UK situation may have been unusual in terms of expected programme availability back in the VHF-only days, coupled with a high proportion of rented rather than owned receivers, such rented receivers probably not moving between districts with their renters, and maybe a lowish level of population mobility anyway. With owned receivers and highish mobility, as say in the USA, being able to receive all available channels in any district would have been a key requirement.