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Cue Dots

(November 2016)

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MA
Markymark
bluecortina posted:
Markymark posted:
bluecortina posted:

With regards to your last sentence, not me, as I know nothing of TVS or Thames' intersite arrangements. With regards your first sentence, why would MCR be involved? It would be the transmission control room switching between an incoming network source and a local source even if it's logically the same source.


I do apologise, it must have been someone else, the ex Thames chap over on DS perhaps ?


Not to worry. I'm trying to rack my brains with regard to mono SIS. I can clearly remember a few of the PYE units knocking around but can't for the life of me remember where they might have been used. I have a feeling radio links? .. but too long ago now I'm afraid.


There was a Pye SiS crate being used as a door-stop at LNN when I did some work there in 2001 ! Cool
NG
noggin Founding member
bluecortina posted:
Markymark posted:
bluecortina posted:

With regards to your last sentence, not me, as I know nothing of TVS or Thames' intersite arrangements. With regards your first sentence, why would MCR be involved? It would be the transmission control room switching between an incoming network source and a local source even if it's logically the same source.


I do apologise, it must have been someone else, the ex Thames chap over on DS perhaps ?


Not to worry. I'm trying to rack my brains with regard to mono SIS. I can clearly remember a few of the PYE units knocking around but can't for the life of me remember where they might have been used. I have a feeling radio links? .. but too long ago now I'm afraid.


SIS was used on microwave and satellite contributions by broadcasters ISTR. I guess LWT may have used it for microwave OB contribution circuits - though I'm guessing satellite downlinks would have been handled elsewhere?
TC
TonyCurrie
Si-Co posted:


As for Tony Currie's impromptu carol singing one Christmas Eve when STV's (part?)networked service from Bridge of Allan failed - I'm inclined to believe that the tale of his local continuity/singing going out across the network is somewhat exaggerated. (*waits for Tony to angrily correct me*) Why would TSW/Ulster/Tyne Tees etc choose to show an (albeit very nice!) Scottish fellow sitting in front of a thistle (or other STV-backdrop) when Ian Stirling, Julian Simmons or Bill Steel were readily available to plug the gap themselves. There was also no real reason for the feed from STV to be dirty, although I've seen a glimpse of Central continuity where it shouldn't have been when they networked the Christmas Eve mass in 1990.


Well, Si-Co, you patently weren't there and I was. The Director of Programmes, David Johnstone, phoned me at home on Christmas Day and told me what had happened. David was not prone to either making up stories or exaggerating (he didn't have the imagination, frankly) and I accept his version of events - in the junction before the Carol Service, our CTA had 'dirtied up' our feed in a panic and the companies taking the programme (five, I think) wre content to take the feed. Remember, it was Christmas Eve, and other announcers might have been relaxing (as indeed I was with a box of cigars minutes before I had to leap into action). Why the other companies didn't do their own thing I will never know! (Sadly no recordings hev ever emerged, otherwise it might be clearer) But remember, half way through we restored sound and added a slide of a stained glass church window....
TC
TonyCurrie
Markymark posted:


Taking things to an extreme, it might have been the case, that
a networked item from Grampian, as seen on STV, would have physically travelled all the way to London,
and all the way back to Glasgow. A path of 1000 miles. Not brilliant for quality ?

You under-estimate the quality of the SHF network. There was little visible deterioration. Have you ever watched BBC-1 analogue from the Voe transmitter in Shetland? Clean, bright, sharp pictures that took an SHF path all the way from London to Rosemarkie, then rebroadcast by Rumster Forest, then rebroadcast by Keelylang Hill (over a lengthy sea path) then picked up in Fair Isle (over another sea path) and SHF lined to Bressay, then rebroadcast by Voe. No discernible impairment (on a monitor in a BBC Reception testing vehicle) although of course you could see some small impairments on a scope.
TC
TonyCurrie
dvboy posted:
TonyCurrie posted:
I
Deejay is right, and at the BBC we still have standbys all over the place. Every programme being played out from a server is simultaneously being played out from another server, and sometimes late at night (when some crew go home) we have a VT running as third backup. For every live sports broadcast there are enough standbys to fill the entire event, and usually of mixed durations. Plus we have episodes of 'Coast' and other short programmes at every conceivable duration! (Did anyone spot the 'Coast' this afternoon when the Tennis finished early in BBC TWO?) Here in Glasgow we also have a filler "Blethering Scots" which is equally handy.


I noticed Coast today too then Hairy Bikers (I wish they'd add some variety). When sport finishes early do you take continuity from Network or do your own thing in Glasgow?

We do our own thing!
MA
Markymark
TonyCurrie posted:
Markymark posted:


Taking things to an extreme, it might have been the case, that
a networked item from Grampian, as seen on STV, would have physically travelled all the way to London,
and all the way back to Glasgow. A path of 1000 miles. Not brilliant for quality ?

You under-estimate the quality of the SHF network. There was little visible deterioration. Have you ever watched BBC-1 analogue from the Voe transmitter in Shetland? Clean, bright, sharp pictures that took an SHF path all the way from London to Rosemarkie, then rebroadcast by Rumster Forest, then rebroadcast by Keelylang Hill (over a lengthy sea path) then picked up in Fair Isle (over another sea path) and SHF lined to Bressay, then rebroadcast by Voe. No discernible impairment (on a monitor in a BBC Reception testing vehicle) although of course you could see some small impairments on a scope.


I've taken a very keen interest in the technical quality of TV channels as I've travelled around the UK the last
35 years or so. To be honest, I recall seeing Eitshal's output in 1991. I wasn't terribly impressed. Best quality pictures was the locally (Aberdeen) stuff on Grampian (as you'd expect). The other three channels were so-so.

Of course post 1993 for C4, and post 1995 for the BBC, digital video distribution circuits were employed, so that removes any possible impairment as far as the regional centre.

The real killer for quality were re-broadcast links through high power UHF transmitters, klystrons are hideously
non linear amplifiers, and do unspeakable things to a baseband video signal. SHF links (and most relay stations) keep everything in the IF/RF domain, and impairment is consequently minimal.

I'd rather have been on the end of a 6 hop SHF BT link, than a single UHF RBL link.

Today, it's all digits of course, but that still leads to issues in cascaded TV relays, another story......
NG
noggin Founding member
Markymark posted:

Of course post 1993 for C4, and post 1995 for the BBC, digital video distribution circuits were employed, so that removes any possible impairment as far as the regional centre.

BBC was only digitally distributed to the regional centres wasn't it (140Mbs PAL circuits ISTR)?

Distribution from regional centres to transmitters could be - and often was - analogue microwave still. That was certainly the case well after 1995 in the BBC East region, where analogue microwave circuits linked Tacolnestone, Sudbury and Sandy Heath, though from 1997 there was a digital fibre circuit from BBC Cambridge to Sandy Heath to carry the Look East Close Up sub-opt, the BBC One East dirty feed from Norwich had been through a microwave circuit (and when soft opted more than one microwave circuit and a PAL 4fsc synchroniser...)
MA
Markymark
noggin posted:
Markymark posted:

Of course post 1993 for C4, and post 1995 for the BBC, digital video distribution circuits were employed, so that removes any possible impairment as far as the regional centre.

BBC was only digitally distributed to the regional centres wasn't it (140Mbs PAL circuits ISTR)?


I think that's what I said ! Cool

In Scotland I'm not sure whether the 140 Mb/s circuits extended further up to Aberdeen as well ?

The move to those circuits also altered the distribution paths in southern England. Southampton was fed
via Bristol, that allowed the then 'macro regional' Westminster programme opt from Bristol to happen without involving London.
BC
Blake Connolly Founding member
thegeek posted:
I was going to comment on here about the short time for line-up, but it appears that bluecortina has covered most of it already. A current colleague worked at LWT MCR once upon a time, and has regaled me with many stories of having about 10 seconds between the BT switch happening and the network programme being on air - and how you could find out very quickly which source you were looking at by way of a unique combination of tones known as "duotone". I just Googled it to find out a little more, and found this DS post which looks like it may have been by bluecortina in a past life Smile


The thought of having that little time for line-up gives me palpitations!
SP
Steve in Pudsey
TonyCurrie posted:
But remember, half way through we restored sound and added a slide of a stained glass church window....


I guess that sound feed was provided down a standard phone line? Slightly surprising that it hadn't been set up as a reserve feed as a matter of course.
GE
thegeek Founding member
Blake Connolly posted:
thegeek posted:
I was going to comment on here about the short time for line-up, but it appears that bluecortina has covered most of it already. A current colleague worked at LWT MCR once upon a time, and has regaled me with many stories of having about 10 seconds between the BT switch happening and the network programme being on air - and how you could find out very quickly which source you were looking at by way of a unique combination of tones known as "duotone". I just Googled it to find out a little more, and found this DS post which looks like it may have been by bluecortina in a past life Smile


The thought of having that little time for line-up gives me palpitations!

ditto! The same chap also told me that HTV had turned down the luminance on these bars to prevent burn-in on their monitors. He didn't know this, so adjusted the luminance at his end accordingly, and when the programme started, it was far too sat-up, so he had to leap back on the equaliser and turn it all back again.
MA
Markymark
Steve in Pudsey posted:
TonyCurrie posted:
But remember, half way through we restored sound and added a slide of a stained glass church window....


I guess that sound feed was provided down a standard phone line? Slightly surprising that it hadn't been set up as a reserve feed as a matter of course.


It may have been the 'intended' music quaility audio circuit. Back in the dark days before telco de-regulation the broadcasters were only allowed to provide links if the GPO were unable to 'practicably do so'. A few 405 line transmitters had SHF vision links operated by the Beeb or ITA, but the audio was still delivered by GPO line, because 'they could'. I'm not sure how far that rule extended into OBs, but I do recall summer 1980 when there was a GPO strike, and the BBC were forced to show cricket coverage in vision only, because the GPO were unable to get the audio feeds set up. Instead the usual Test Card/Pages from Ceefax music continued over the pictures, with the occasional apology Aston.

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