Mass Media & Technology

Early days of NICAM Stereo

(September 2017)

This site closed in March 2021 and is now a read-only archive
MA
Markymark
noggin posted:

Were there multiple flavours of DSIS? ISTR that there were various flavours of one type of SIS or the other.

From memory the BBC used Dual Sound-In-Syncs (aka DSIS) on the output of their studio centres to feed the transmitters - and the data format used for DSIS was identical to NICAM, so removed the need for NICAM digital encoders at every transmitter (instead just needing some shuffling and modulators)?


Other way round. The IBA DSIS was NICAM 728 based, so no transcode required between studio and receiver. The BBC used the same format as their national radio distribution, NICAM 3 ? 656kHz based, so transcoding required at the tx sites. The Beeb opted for that to make spares interchangeable between the radio and TV networks. The IBA were dealing with 'green field' so made perfect sense to go with 728.
NG
noggin Founding member
Markymark posted:
noggin posted:

Were there multiple flavours of DSIS? ISTR that there were various flavours of one type of SIS or the other.

From memory the BBC used Dual Sound-In-Syncs (aka DSIS) on the output of their studio centres to feed the transmitters - and the data format used for DSIS was identical to NICAM, so removed the need for NICAM digital encoders at every transmitter (instead just needing some shuffling and modulators)?


Other way round. The IBA DSIS was NICAM 728 based, so no transcode required between studio and receiver. The BBC used the same format as their national radio distribution, NICAM 3 ? 656kHz based, so transcoding required at the tx sites. The Beeb opted for that to make spares interchangeable between the radio and TV networks. The IBA were dealing with 'green field' so made perfect sense to go with 728.


That's a surprise !
MA
Markymark
noggin posted:
Markymark posted:
noggin posted:

Were there multiple flavours of DSIS? ISTR that there were various flavours of one type of SIS or the other.

From memory the BBC used Dual Sound-In-Syncs (aka DSIS) on the output of their studio centres to feed the transmitters - and the data format used for DSIS was identical to NICAM, so removed the need for NICAM digital encoders at every transmitter (instead just needing some shuffling and modulators)?


Other way round. The IBA DSIS was NICAM 728 based, so no transcode required between studio and receiver. The BBC used the same format as their national radio distribution, NICAM 3 ? 656kHz based, so transcoding required at the tx sites. The Beeb opted for that to make spares interchangeable between the radio and TV networks. The IBA were dealing with 'green field' so made perfect sense to go with 728.


That's a surprise !


I remember TV-am being a few months behind TVS with NICAM. The carrier would vanish between 06:00hrs and 09:25hrs, I couldn't understand why, so I phoned Crawley Court and spoke to an IBA engineer who explained why, and the difference between BBC and IBA implementation
VM
VMPhil
This is a TOTP performance from May 1988 in stereo. The Radio 1 FM simulcast didn't start until September, so it appears they were producing the show in stereo long before then. I wonder when stereo TOTP broadcasts started from Crystal Palace.

NG
noggin Founding member
VMPhil posted:
This is a TOTP performance from May 1988 in stereo. The Radio 1 FM simulcast didn't start until September, so it appears they were producing the show in stereo long before then. I wonder when stereo TOTP broadcasts started from Crystal Palace.

https://www.youtube.com/watch?v=pe4_3EazskA


Wouldn't be surprised if they were stereo from the start of the CP tests. There was a reasonable amount in '86 or '87 from memory.
VM
VMPhil
noggin posted:
VMPhil posted:
This is a TOTP performance from May 1988 in stereo. The Radio 1 FM simulcast didn't start until September, so it appears they were producing the show in stereo long before then. I wonder when stereo TOTP broadcasts started from Crystal Palace.

https://www.youtube.com/watch?v=pe4_3EazskA


Wouldn't be surprised if they were stereo from the start of the CP tests. There was a reasonable amount in '86 or '87 from memory.

Will be interesting to see at what point the BBC Four repeats go from mono to stereo then. Unfortunately the 1000th edition (which was in stereo and simulcast on FM) was Yewtree'd, so not sure whether their copy would have had a stereo soundtrack or not.


Remind me to reopen this thread in a year's time when they get to July 1986!
JA
JAS84
Would they get there that soon? They're only on Spring 1984 at the moment, and there shouldn't be too many more banned episodes left.
VM
VMPhil
JAS84 posted:
Would they get there that soon? They're only on Spring 1984 at the moment, and there shouldn't be too many more banned episodes left.

They're doing two years within one year now. So next year will be presumably be 1985 and 1986.
FA
far
There used to be a great site which included clips of early NICAM test transmissions including the very first test mentioned in this thread from Crystal Palace. I still have all the audio clips from that site as MP3s but, alas, I believe the site has long since vanished into thin air Sad
IS
Inspector Sands
That'll be the vintage broadcasting site. The text had made it into archive.org but not the images or audio: https://web.archive.org/web/20031002022304/http://www.vintagebroadcasting.org.uk:80/bbcnicam.htm
FA
far
That's the one! I still have the MP3 files sitting on my hard drive, wonder if its worth uploading them somewhere?
VM
VMPhil
Would love to hear them, if it's not too much trouble to get them uploaded. Smile

If you have a Metropol account, the easiest way to upload them is there: https://www.metropol247.co.uk/uploadservice/
far and Inspector Sands gave kudos

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