The ( extra) delay is caused by the change of transport layer (MPLS) of the distribution, the new NICAM codecs are just 'swap outs' of the old 1983 kit. The distribution circuit change is a gradual roll out
Some eight months after I started this thread, Rowridge and Wrotham are still not in sync. I measured it today at 90ms. Rowridge is behind Wrotham.
I wonder if they are delaying changing Wrotham as long as possible as it will make presenter off air monitoring at BH impossible. Maybe they don't do that anyway?
Actually it is very annoying. The car radio frequently switches between the two where I work and it's like listening to a bad CD. The delay is enough to hear the same beat on music or part word on speech twice. Less noticeable when the switch is the other way round.
One of my colleagues thought their car radio was going wrong.
If it wasn't for RDS switching I'd agree that this wouldn't matter.
Actually it is very annoying. The car radio frequently switches between the two where I work and it's like listening to a bad CD. The delay is enough to hear the same beat on music or part word on speech twice. Less noticeable when the switch is the other way round.
One of my colleagues thought their car radio was going wrong.
If it wasn't for RDS switching I'd agree that this wouldn't matter.
Yes, I've had similar comments from friends, it's irritating enough to drive you to using DAB, ah, hang on a moment..........
I have submitted a complaint to the BBC, but I expect it will fall into the category of the person reading it not really understanding what I've written.
Heard it again this morning and Sutton Coldfield is behind Wenvoe I think. When the radio flicks from 94.3 to 92.7 there's a slight stuttering echo sound.
Heard it again this morning and Sutton Coldfield is behind Wenvoe I think. When the radio flicks from 94.3 to 92.7 there's a slight stuttering echo sound.
I have a list of main transmitters that are on the new MPLS dist, and therefore delayed
Blaenplwyf -
Divis -
Llandonna -
North Hessary Tor
Pontop Pike -
Rowridge -
Sandale -
Sutton Coldfield - (and therefore Oxford too)
Tacolneston -
Notable absences from that list, Wrotham, Holme Moss, Wenvoe, Peterborough, and everything in Scotland
I have submitted a complaint to the BBC, but I expect it will fall into the category of the person reading it not really understanding what I've written.
I have a list of main transmitters that are on the new MPLS dist, and therefore delayed
Blaenplwyf -
Divis -
Llandonna -
North Hessary Tor
Pontop Pike -
Rowridge -
Sandale -
Sutton Coldfield - (and therefore Oxford too)
Tacolneston -
Notable absences from that list, Wrotham, Holme Moss, Wenvoe, Peterborough, and everything in Scotland
That's interesting - I compared Sutton to Holme Moss yesterday, and they both seemed to be in time, suggesting that maybe Holme Moss is on the new circuits. It'd be a bit of a mess otherwise, as Llangollen (a relay of Sutton C) has a huge overlap with HM.
That's interesting - I compared Sutton to Holme Moss yesterday, and they both seemed to be in time, suggesting that maybe Holme Moss is on the new circuits. It'd be a bit of a mess otherwise, as Llangollen (a relay of Sutton C) has a huge overlap with HM.
Is the list above official i.e. from Arqiva?
Someone I know within the broadcast industry passed me the list, it may not be 100% up to date though, so perhaps HM is on the new network (or had a delay fitted !)
That's interesting - I compared Sutton to Holme Moss yesterday, and they both seemed to be in time, suggesting that maybe Holme Moss is on the new circuits. It'd be a bit of a mess otherwise, as Llangollen (a relay of Sutton C) has a huge overlap with HM.
Is the list above official i.e. from Arqiva?
Well this is interesting, as last week I couldn't hear any difference between Oxford and Wrotham. I will check again later.
Well this is interesting, as last week I couldn't hear any difference between Oxford and Wrotham. I will check again later.
Just checked, no delay between Wrotham and Oxford.
So either Sutton Coldfield (and hence Oxford) hasn't yet been moved to the MPLS or we shouldn't be seeing such a massive delay on Rowridge as 90ms.
Just checked, no delay between Wrotham and Oxford.
So either Sutton Coldfield (and hence Oxford) hasn't yet been moved to the MPLS or we shouldn't be seeing such a massive delay on Rowridge as 90ms.
There is a slight delay between Oxford and Wrotham, it's very slight, nowhere near the difference between either site and Rowridge. Thing is MPLS can have variable latancy !
I wonder if they are delaying changing Wrotham as long as possible as it will make presenter off air monitoring at BH impossible. Maybe they don't do that anyway?
Not sure, but they do monitor Wrotham at NBH.
They have software too which analyses what leaves NBH and what goes out at Wrotham (amongst other sites) to check for faults. I saw the software mid last year and I believe if I remember rightly that it was developed by Sonifex.
Last year the software picked up a slight L-R balance issue on R1 that was not present in the audio that left NBH. Clever stuff.
I understand you have concerns the Wrotham and Rowridge VHF transmitters have been out of sync since last year.
May I begin by apologising for the inconvenience and thank you for bearing with us while the network is updated and improved.
The audio glitching is caused by an ongoing programme of works to update the distribution links between the BBC and our transmitters. Our transmitter network supplier, is migrating the radio transmitters on a site by site basis. In the area you mention, you are likely to be receiving radio from the Rowridge and Wrotham transmitters. Rowridge has already migrated to the new system, but Wrotham transmitter is still on the old system. The two signals are correctly timed however because of the change of technology the Rowridge signal is slightly behind Wrotham. This manifests itself as a slight stutter when the frequency changes.
This effect should disappear when Wrotham switches over to the new technology although we do not know a final date for the change as yet.
There is a slight delay between Oxford and Wrotham, it's very slight, nowhere near the difference between either site and Rowridge. Thing is MPLS can have variable latancy !
There's a slight FM lift here at the moment, allowing me to hear Tacolneston and Peterborough in stereo, as well as Holme Moss and Sutton Coldfield.
TAC is well behind all TX's, but P'borough and HM (both still on NICAM?) are only slightly ahead of SC, but it's very slight.
It's interesting to hear how big the delay is between TAC and SC, considering they are both on the MPLS circuits!
Well I'm pleased to say that Wrotham and Rowridge no longer have a delay between them.
Noticed last week that I hadn't heard the car radio skip for a little while and checked between all the transmitters I could hear and they are all timed together.
Well I'm pleased to say that Wrotham and Rowridge no longer have a delay between them.
Noticed last week that I hadn't heard the car radio skip for a little while and checked between all the transmitters I could hear and they are all timed together.
What's the deal elsewhere in the country?
On Radio 4, Oxford and Sutton Coldfield are in sync with each other; Bow Brickhill is out of sync with those two.
Comments
I have found some details of an earlier study into MPLS for broadcast.
https://tech.ebu.ch/docs/techreview/trev_2012-Q1_all-ip_network_nicholson.pdf
As the NICAM equipment needed replacing, I'm surprised the BBC are staying with NICAM as they are changing the 'pipes' to the TX sites.
Yes, I share your surprise
Thanks for the link to that report, an interesting read!
I wonder if they are delaying changing Wrotham as long as possible as it will make presenter off air monitoring at BH impossible. Maybe they don't do that anyway?
Actually it is very annoying. The car radio frequently switches between the two where I work and it's like listening to a bad CD. The delay is enough to hear the same beat on music or part word on speech twice. Less noticeable when the switch is the other way round.
One of my colleagues thought their car radio was going wrong.
If it wasn't for RDS switching I'd agree that this wouldn't matter.
Yes, I've had similar comments from friends, it's irritating enough to drive you to using DAB, ah, hang on a moment..........
Lucky you for not being affected then
I have a list of main transmitters that are on the new MPLS dist, and therefore delayed
Blaenplwyf -
Divis -
Llandonna -
North Hessary Tor
Pontop Pike -
Rowridge -
Sandale -
Sutton Coldfield - (and therefore Oxford too)
Tacolneston -
Notable absences from that list, Wrotham, Holme Moss, Wenvoe, Peterborough, and everything in Scotland
Yes. They'll probably blame this week's weather.
That's interesting - I compared Sutton to Holme Moss yesterday, and they both seemed to be in time, suggesting that maybe Holme Moss is on the new circuits. It'd be a bit of a mess otherwise, as Llangollen (a relay of Sutton C) has a huge overlap with HM.
Is the list above official i.e. from Arqiva?
Someone I know within the broadcast industry passed me the list, it may not be 100% up to date though, so perhaps HM is on the new network (or had a delay fitted !)
Well this is interesting, as last week I couldn't hear any difference between Oxford and Wrotham. I will check again later.
Just checked, no delay between Wrotham and Oxford.
So either Sutton Coldfield (and hence Oxford) hasn't yet been moved to the MPLS or we shouldn't be seeing such a massive delay on Rowridge as 90ms.
There is a slight delay between Oxford and Wrotham, it's very slight, nowhere near the difference between either site and Rowridge. Thing is MPLS can have variable latancy !
Not sure, but they do monitor Wrotham at NBH.
They have software too which analyses what leaves NBH and what goes out at Wrotham (amongst other sites) to check for faults. I saw the software mid last year and I believe if I remember rightly that it was developed by Sonifex.
Last year the software picked up a slight L-R balance issue on R1 that was not present in the audio that left NBH. Clever stuff.
I understand you have concerns the Wrotham and Rowridge VHF transmitters have been out of sync since last year.
May I begin by apologising for the inconvenience and thank you for bearing with us while the network is updated and improved.
The audio glitching is caused by an ongoing programme of works to update the distribution links between the BBC and our transmitters. Our transmitter network supplier, is migrating the radio transmitters on a site by site basis. In the area you mention, you are likely to be receiving radio from the Rowridge and Wrotham transmitters. Rowridge has already migrated to the new system, but Wrotham transmitter is still on the old system. The two signals are correctly timed however because of the change of technology the Rowridge signal is slightly behind Wrotham. This manifests itself as a slight stutter when the frequency changes.
This effect should disappear when Wrotham switches over to the new technology although we do not know a final date for the change as yet.
There's a slight FM lift here at the moment, allowing me to hear Tacolneston and Peterborough in stereo, as well as Holme Moss and Sutton Coldfield.
TAC is well behind all TX's, but P'borough and HM (both still on NICAM?) are only slightly ahead of SC, but it's very slight.
It's interesting to hear how big the delay is between TAC and SC, considering they are both on the MPLS circuits!
You're correct. HM is in time with 198 longwave, SC is slightly behind, and TAC is well behind!
Noticed last week that I hadn't heard the car radio skip for a little while and checked between all the transmitters I could hear and they are all timed together.
What's the deal elsewhere in the country?
On Radio 4, Oxford and Sutton Coldfield are in sync with each other; Bow Brickhill is out of sync with those two.