8-bit Computer TV Channel Use

Mark J. Blair nf6x at nf6x.net
Tue May 19 16:46:26 CDT 2015

> On May 19, 2015, at 13:47, tony duell <ard at p850ug1.demon.co.uk> wrote:
> Most, if not, all home computers sold to connect to TVs in the UK were set to use our UHF channel 36.

> VHF channels were not used for broadcast 625 line TV in the UK, and most TVs could not tune to them. So you
> will not find a UK home computer using VHF RF output.

Thanks! Those are the sorts of details that are hard to know with only my US computer/TV experience. 

That NTSC ZX-81 is the first I have heard of a computer with UHF TV output in the U.S., but it makes sense to minimize the hardware changes for the U.S. market. Might have used the same modulator, possibly with a coil adjusted a bit differently in the factory. 

Native US gear was all VHF in my experience. Usually switchable between channels 3 and 4 to avoid whichever channel had a strong local station, and also commonly using an Astec modulator. I still have a nagging feeling that I might have seen something with channel 2 output, but can't remember where I think I saw it. 

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