19-08-2023, 05:49 PM
A breakdown happened just now on BBC1 between the local news and the national weather, with the latter not appearing at all.
(19-08-2023, 05:58 PM)Andrew Wrote: Looking on iPlayer, BBC London held on the end of their bulletin, meaning the presenter had to sit there shuffling their papers for over a minute
Elsewhere, surprised they can broadcast the visual equivalent of dead air for so long before an fault caption pops up
(19-08-2023, 08:36 PM)Bennyboy84 Wrote: Doesn’t TV “Dead Air” get overridden automatically kind of like radio does if it’s silent for a certain amount of time it goes to a backup tape. Or is it a case of if something fails to play and ends up on a still or black it will stay there until whatever is being output for us to see is switched to something else?
(19-08-2023, 08:50 PM)Neil Jones Wrote: Depends on the definition of dead air and the era.
If its dead air as in transmitting something that just happens to be a black screen for whatever reason, that may require somebody to intervene to get something else on air. Usually an OB has packed up or something or a source has suddenly become unavailable but the channel itself is still "on air". Case in point: The One Show once had a fire alarm, they showed a VT, evacuated, the VT ran out and there was a black screen for a while until presentation took over.
Prior to I believe 1991 the IBA transmitters if they lost their source would show you a blue screen generated by the transmitter, though sometimes the sound would come through but not the picture for some reason. Some examples on YouTube.
In the digital era not sure what happens if the Freeview transmitters lose their source, but I presume its just a frozen picture.
Radio has the backup tape (which can on occasion reveal its age and the last time it was updated) due to the medium, as its usually the station itself is still "on air", just transmitting the audio equivalent of nothing. I believe as as its an audio medium it has no other output. Few examples where the fire alarm has gone off and cut the studio output to prevent that from going out on air, but equally some examples of where it has gone out on air and they've managed to segway gracefully into the backup material. Example: Radio 5.
(19-08-2023, 08:50 PM)Neil Jones Wrote: Depends on the definition of dead air and the era.There's two different things; there's loss of content and loss of signal.
If its dead air as in transmitting something that just happens to be a black screen for whatever reason, that may require somebody to intervene to get something else on air. Usually an OB has packed up or something or a source has suddenly become unavailable but the channel itself is still "on air". Case in point: The One Show once had a fire alarm, they showed a VT, evacuated, the VT ran out and there was a black screen for a while until presentation took over.
Prior to I believe 1991 the IBA transmitters if they lost their source would show you a blue screen generated by the transmitter, though sometimes the sound would come through but not the picture for some reason. Some examples on YouTube.
In the digital era not sure what happens if the Freeview transmitters lose their source, but I presume its just a frozen picture.
Quote:Radio has the backup tape (which can on occasion reveal its age and the last time it was updated) due to the medium, as its usually the station itself is still "on air", just transmitting the audio equivalent of nothing. I believe as as its an audio medium it has no other output. Few examples where the fire alarm has gone off and cut the studio output to prevent that from going out on air, but equally some examples of where it has gone out on air and they've managed to segway gracefully into the backup material. Example: Radio 5.Radio is simpler, only one thing to detect: 'is there audio, or is there no audio?' Also it's still transmitted in analogue so it's possible to have a silence detector at an FM or MW transmitter. But like in TV, if one station in a DAB multiplex goes silent then that's not going to be detected, it has to be done at the station while it's still exists as audio.