TV Mistakes/Breakdowns - Printable Version

+- Pres Café (https://pres.cafe)
+-- Forum: Pres Café TV and Radio Forums (https://pres.cafe/forumdisplay.php?fid=1)
+--- Forum: Channel Presentation (https://pres.cafe/forumdisplay.php?fid=2)
+--- Thread: TV Mistakes/Breakdowns (/showthread.php?tid=16)

---

RE: TV Mistakes/Breakdowns - Bennyboy84 - 20-08-2023

A couple of examples of emergency tapes having to kick in…

https://youtu.be/WGpXMesa2oQ 

https://youtu.be/ULQZMbujtz0 

---

RE: TV Mistakes/Breakdowns - Bennyboy84 - 20-08-2023

(20-08-2023, 01:50 AM)Stooky Bill Wrote:  Loss of video signal - i.e. the SDI video, or the transport stream is missing or corrupt. This is something that is also detected, but will automatically switch between main and reserve paths... assuming the other one is good. These sort of switches do so instantaneously and often are barely noticable on air.

So in the case of the Britain’s Got Talent fault of 2018 where the severe thunderstorm over London caused it to be off air for over 10 minutes, I’m guessing it took out the main and reserve so what we saw was this…

https://youtu.be/usrDEOrMgfw 

In some regions a test card also was seen.

---

RE: TV Mistakes/Breakdowns - Stooky Bill - 20-08-2023

(20-08-2023, 01:44 PM)Bennyboy84 Wrote:  So in the case of the Britain’s Got Talent fault of 2018 where the severe thunderstorm over London caused it to be off air for over 10 minutes, I’m guessing it took out the main and reserve so what we saw was this…

https://youtu.be/usrDEOrMgfw 

In some regions a test card also was seen.

That's a bit different, that's an OB failing. Yes you are seeing a main and reserve, but they'll both be into ITV presentation and the transmission controller/director will have needed to cut the reserve to air.

The source that says 'no signal detected' is a satellite receiver/decoder, the colour bars are from SIS, looks like some sort of decoder (and interesting spelling of 'media'). Both of those will either be synchronised into the building, or a local device so end up on air as proper good video, there'll be no loss of signal into the TX chain and it won't try and switch paths. 

That breakdown is a good example of path diversity. They had a main and a reserve, looks like they were being downlinked in two places, and they maybe were using two satellites.... but the single point of failure was the the weather. It's why broadcasters specify two diverse routes, but that's not always possible. Easier these days as IP solutions are improved, you can get a land based link from more places than ever

Incidently I remember being told that OnDigital's two diverse transmission paths originally went over the same bridge 

---

RE: TV Mistakes/Breakdowns - Stooky Bill - 20-08-2023

(20-08-2023, 11:50 AM)Bennyboy84 Wrote:  A couple of examples of emergency tapes having to kick in…

https://youtu.be/ULQZMbujtz0 

I remember hearing about that at the time, but hadn't heard it till now. Brilliant. 

I used to know someone who did something very similar and turned off a Soho post production facility with his belt. 

A good example of how radio station playout systems are set up. When the studio power failed the promo kept playing and ended nice and clean. The system playing the audio isn't in the studio they're just being controlled remotely from the studio. So when the studio failed the playout system finished what it was playing and didn't know what to do next. In the old days you'd have got a bit of a noise and then silence as soon as the desk was depowered

---

RE: TV Mistakes/Breakdowns - i.h - 20-08-2023

perhaps the most famous example of alleged "path diversity" is when the BBC lost their radio distribution network for a few hours as a series of failures led to both legs passing through the same overheating building, and a separate fault broke RBS for points north of & including Sutton Coldfield too

an FOI request delivered all the detail you could ever want - https://www.lamont.me.uk/broadcast/ 

---

RE: TV Mistakes/Breakdowns - robertclark125 - 20-08-2023

Back when the BBC showed open university programmes, what happened if there was a breakdown during one? Would they delay other programmes to try and return to the programme, or reschedule it, with students on the course being informed by the OU of when it would be shown again? And was there a breakdown slide for the OU as it didn't, until the early 1990s, come from nc1 or nc2.

---

RE: TV Mistakes/Breakdowns - Steve in Pudsey - 20-08-2023

Reg Sanders, a BBC Announcer who had to operate OU Con posted the operating instructions for it on Twitter a while ago. This included mention of a fault caption being available on the slidefile.

---

RE: TV Mistakes/Breakdowns - thegeek - 21-08-2023

(20-08-2023, 02:20 PM)Stooky Bill Wrote:  The source that says 'no signal detected' is a satellite receiver/decoder, the colour bars are from SIS, looks like some sort of decoder (and interesting spelling of 'media'). Both of those will either be synchronised into the building, or a local device so end up on air as proper good video, there'll be no loss of signal into the TX chain and it won't try and switch paths. 

The 'no signal detected' screen is indeed a satellite decoder (probably the venerable Ericsson/MediaKind RX8200). The flashes of green are probably brief bits of it outputting invalid SDI video before it noticed and put out the error message instead.
The SIS 'Meida City' bars are actually generated by an encoder (providing a link from Salford to ITV's contribution network, possibly via BT Tower), and pop up on a loss of input. SIS, now NEP Connect, have a downlink station there.

So I think what happened was:
- RF stage loses signal
- Video decoder loses lock, then holds on to the last frame, then outputs black, then a few seconds of no valid video
- IVNP encoder pops up its bars
- Sat decoder starts outputting valid SDI black, which IVNP encoder starts sending again
- Sat decoder outputs signal loss message
- playout director cuts to the reserve, possibly not noticing that it's also on a glitchy freeze frame
- Playout director reaches for their breakdown slide and standby material.

---

RE: TV Mistakes/Breakdowns - Bluecortina - 21-08-2023

(20-08-2023, 02:20 PM)Stooky Bill Wrote:  That's a bit different, that's an OB failing. Yes you are seeing a main and reserve, but they'll both be into ITV presentation and the transmission controller/director will have needed to cut the reserve to air.

The source that says 'no signal detected' is a satellite receiver/decoder, the colour bars are from SIS, looks like some sort of decoder (and interesting spelling of 'media'). Both of those will either be synchronised into the building, or a local device so end up on air as proper good video, there'll be no loss of signal into the TX chain and it won't try and switch paths. 

That breakdown is a good example of path diversity. They had a main and a reserve, looks like they were being downlinked in two places, and they maybe were using two satellites.... but the single point of failure was the the weather. It's why broadcasters specify two diverse routes, but that's not always possible. Easier these days as IP solutions are improved, you can get a land based link from more places than ever

Incidently I remember being told that OnDigital's two diverse transmission paths originally went over the same bridge 

Am I right in thinking this particular problem was quickly overcome by an enterprising links engineer pointing a conventional microwave dish towards BBC tv centre where the signal was picked up and relayed to BT tower then onwards to Chiswick?

---

RE: TV Mistakes/Breakdowns - Stooky Bill - 21-08-2023

(21-08-2023, 12:03 PM)Bluecortina Wrote:  Am I right in thinking this particular problem was quickly overcome by an enterprising links engineer pointing a conventional microwave dish towards BBC tv centre where the signal was picked up and relayed to BT tower then onwards to Chiswick?

That wouldn't be this occasion as it was 5 years after TV Centre closed. I think they just had to wait till the weather passed 

There was an incident when they were at Fountain Studios in Wembley where the BBC helped out. IIRC that was a big failure at BT Tower so if that's what happened then  presumably the BBC either uplinked it to satellite or used some other connectivity to ITV or ITN.

There was one X Factor/BGT failure, might be the same as the above, where there was a satellite path for Irish TV and that was used - with the BBC downlinking it and passing it on to ITV

---