The TV Question Amnesty Thread

They do. Are you getting it mixed up with The Channel Islands?

That’s it. I knew one didn’t have an HD service.

Yes, no ITV HD on the Channel Islands, it's not a technical issue, in previous discussions we've concluded it's in the transport stream, it's just chopped out of the SI tables so it cannot be received. It's to do with some legal or commercial issue regarding ITV Channel and its status within ITV Plc. Remember overnight gambling dross has to be blanked out on ITV Channel's SD feed. It's too small to have a commercially viable bespoke HD channel (though it'll probably get one before any BBC region does! 😝 )

I’m not a professional but could they just drop the channel in the SI table over night? I heard the FreeView tuners automatically know when services are added within a MUX without rescanning?

Is ITV HD available via Freesat or Sky?

Not sure what you mean by the first question.

Not sure whether the channel appears in the EPG on CI postcode regisisted Freesat and Sky systems, but that's more easily circumvented

You mentioned that ITV HD is dropped from the SI table in the MUX, is it possible for them to add it to the SI table during the day and remove it at night? So the channel can be essentially turned on/off as needed and if that’s possible would the Freeview receivers need to be returned every time?

Oh, I see. Yes, I suppose, but I suspect the impediment to the channel being available is more complex than just the overnight gambling

Was CEEFAX a BBC only service in the UK or could ITV have their own version? How did it work would you have to be tuned to the BBC to watch or could you be on any channel?

Ceefax was the name of BBC's teletext service available on BBC One and BBC Two.
ITV's was totally seperate provided by ORACLE until 1993 when they lost the franchise to Teletext Ltd.

Ceefax and Oracle (later Teletext) were just brand names for the teletext services. Ceefax could only be received on the BBC channels and Oracle was on ITV and (later) Channel 4.

It's set up in such a way that if you had a teletext capable TV you could access the data as it was transmitted as part of the picture, and if you didn't have capable hardware, the TV just ignored it. Because it was transmitted as part of the picture (in a nutshell) it's how people have managed to "recover" the pages.

Yes, both systems started off in the early 70s as separate r&d projects by the BBC and IBA

BBC Ceefax is just a play on words, See Facts

IBA Oracle stood for, Optional Reception of Announcements by Coded Line Electronics

I think both started as a means of providing subtitles (closed captions in US speak)

By 1972 both broadcasters had developed incompatible but very similar systems, so they collaborated to
produce what became World Standard Teletext (WST)

The BBC launched Ceefax publicly, followed a short while later by Oracle. Suitably equipped receivers were initially rare and expensive, but the services took off around 1980 ish

WST was used by a number of other broadcasters world wide, (and some services still exist)

Further stuff
http://teletext.mb21.co.uk/

Indeed RTÉ’s Aertel still exists in Ireland - albeit the WST version is now recievable only by people who still connect their Sky boxes via SCART.