Missing Teletext on UK 4

mike65

What is it with the 4 UK terrestrial channels loosing teletext every so often then a few hours later- bingo! - its back.

Very annoying and surly needless, either we have it or we dont.

Mike.

Mredmond

Sounds like you're in Chorus Analogue land, same as me.
My theory is that Chorus occasionally take a signal which they've captured using a Sky Digi-Box, and re-broadcast it over Analog to its customers.
One possible explanation would be that they use this system as a backup when they are performing maintenance, but that 's clearly not the case as Chorus don't seem the type to bother with backup broadcasting arrangements - better to just let the customer wait.

If I remember rightly, mike65 is in NTL land and has godigital.
chorus are a strange lot.
They use digiboxes a lot of the time for sourcing their cable channels and then rebroadcast to the paying customer in mono.
The paying customer should cut out the middle man and go direct to sky-better value for money.

In Arklow Chorus use a mono mmds relay to source their channels:rolleyes:
Methinks theres an astroid belt between their hq there and Astra or something:D
Ceefax regularly used dissapear when I had Chorus mmds.
mm

sceptre

Originally posted by Mredmond
Sounds like you're in Chorus Analogue land, same as me.
My theory is that Chorus occasionally take a signal which they've captured using a Sky Digi-Box, and re-broadcast it over Analog to its customers.

Oh, they definitely do that. Occasionally I noticed the usual page 100 replaced with the analog text page broadcast on digital - the one that says something like "Ceefax is no longer available on channels broadcast on digital signals".

I've a feeling they're not allowed to do this (based on the analog transmissions carrying over borders directive that makes the whole thing possible with a compulsory licence fee as in the US) but at least people get their channels rather than relying on NTL and Chorus to have their full networks (from reception to transmission to reception) in order all the time.

I'd imagine that NTL are doing something similar but they'll orobably never admit to it (unless you come across that Ceefax notification page like I did)

Antenna

I hear that Teletext was missing on UTV on Chorus MMDS in Cork last weekend, with the exception of page 888 subtitles (Is this the way it is on DSAT??)

watty

Analog MMDS as it is should NEVER have been licenced.
It is adapted US cable technology. Microwave TV should always be on FM carrier (like analog Satellite or Analog Microwave links used by broadcasters).

MMDS uses AM Video.

PAL and Telextext etc need nearly 8MHz bandwidth signal. The baseband of PAL is much more then US TV wich uses NTSC

For example the Digital square pixel equivalent of US TV is 640 x480 and of Eurpean PAL is 768 x 576 (DVD / DV doesn't use square pixels so is either 704 x 576 or 720 x 576. PAL DVDs are 20% sharper than US NTSC ones)

So Analog MMDS is not really good enough for Advanced PAL addons like Nicam and Teletext (The US doesn't have teletext).

Most analog cable systems I've seen in Limerick and Dublin are terrible. I wouln't expect Nicam and Teletext on them. Especially not Nicam Stereo. People keep telling me how much better cable is than it used to be..

Yet again the Irish consumer is ripped off by inadequate legislation and safeguards in the Licence.

We could have had Digital Cable and MMDS 10 years ago.

We could have had our own analog Satellite service, FM analog MMDS or Digital MMDS at the time the already obsolete AM Analog MMDS was installed.

The MMDS set-top boxes are obsolete US cable TV boxes. It's a wonder subscribers get colour! (powering the MMDS aerial with a "plug top psu" and feeding a TV directly gives a better picture on the "clear" channels.. and that's still like UK analog "fringe reception" quality).

watty

Originally posted by Antenna
I hear that Teletext was missing on UTV on Chorus MMDS in Cork last weekend, with the exception of page 888 subtitles (Is this the way it is on DSAT??)

Yes.

I have a PC DVBs PCI card on four satellites. I have the 4 Irish Sky channels added too, even though there is no picture and sound. The PC teletext application "caches" ALL the pages and lets you click on page numbers on the teletext. (Makes FastText look slow) Also you can copy text as text or print pages.

You need a very good signal for teletext.

Frameless

Originally posted by watty
Analog MMDS as it is should NEVER have been licenced.
It is adapted US cable technology. Microwave TV should always be on FM carrier (like analog Satellite or Analog Microwave links used by broadcasters).

MMDS uses AM Video.

PAL and Telextext etc need nearly 8MHz bandwidth signal. The baseband of PAL is much more then US TV wich uses NTSC

For example the Digital square pixel equivalent of US TV is 640 x480 and of Eurpean PAL is 768 x 576 (DVD / DV doesn't use square pixels so is either 704 x 576 or 720 x 576. PAL DVDs are 20% sharper than US NTSC ones)

So Analog MMDS is not really good enough for Advanced PAL addons like Nicam and Teletext (The US doesn't have teletext).

Most analog cable systems I've seen in Limerick and Dublin are terrible. I wouln't expect Nicam and Teletext on them. Especially not Nicam Stereo. People keep telling me how much better cable is than it used to be..

Yet again the Irish consumer is ripped off by inadequate legislation and safeguards in the Licence.

We could have had Digital Cable and MMDS 10 years ago.

We could have had our own analog Satellite service, FM analog MMDS or Digital MMDS at the time the already obsolete AM Analog MMDS was installed.

The MMDS set-top boxes are obsolete US cable TV boxes. It's a wonder subscribers get colour! (powering the MMDS aerial with a "plug top psu" and feeding a TV directly gives a better picture on the "clear" channels.. and that's still like UK analog "fringe reception" quality).

People – what is this fascination with the word ‘obsolete’? 8 megs of bandwidth is 8 megs of bandwidth – be it on VHF/UHF or microwave!! Teletext is merely a digital stream ‘piggy-backed’ onto the analogue carrier – so the transmission medium is transparent! The signal doesn’t know (or care!) which route it takes.

Regarding Nicam, as far as I’m aware, the Dublin analogue cable net carries all channels in Nicam stereo and Teletext is available on the majority of channels delivered.

BTW – not all MMDS companies use the alleged ‘antiquated’ American (Jerrold) STBs – NTL (and some Chorus) use modified analogue Pace satellite decoders for the job. And – oh – most of the five major City-based cable nets use Fibre Optic backbone systems, and even towns such a Kilkenny, Clonmel, and Thurles enjoy a full two-way interactive cable net, complete with hi-speed Internet and cable-based (not third-party) telephony.

Even DMMDS (now available in many areas) carries a full compliment of 64 channels. So let’s have our facts straight in future chaps!

watty

The original MMDS that uses "jerrold" boxes does not have full PAL 8 MHz bandwidth (needed for 6MHz baseband) because it was for lower bandwidth USA 525 Line Vistigial AM signal, rather than the 625 Line European Vistigial Sideband AM. So it struggles with Teletext and is unlikely to manage the Nicam Signal. If Chorus use a baseband video connection, you can't get Nicam anyway without a very expensive Nicam coder (This is why VHS and Digibox are only mono via RF connector and stereo playback needs phono or SCART).

The Pace boxes (all Analog Satellite) is FM. About 25MHz bandwidth, though 16 MHz is possible mod for MMDS to give 6MHz baseband needed. Since only alternate channnels are transmitted on any particular MMDS (11 out of 22) and FM is less suseptable to Co-Channell interference, if the Modulator / MMDS transmitter is changed to FM, yes a Pace Analog box will work (The LNB on the MMDS aerial needs to convert to a different band though).
This would be a lot superior to the original US based "Jerrold" system, if done properly.

What areas are using Analog FM then (Pace boxes)?

DMMDS is in theory a good system, better than channels limited UK DTT.

Is anyone actually arguing they PREFER Analog MMDS (or Analog Cable) to Digital Cable, DMMDS or Sky Digital?
(Admittedly in some Limerick areas cable sufferes a lot from getting "hacked").

icdg

Originally posted by sceptre


I've a feeling they're not allowed to do this (based on the analog transmissions carrying over borders directive that makes the whole thing possible with a compulsory licence fee as in the US) but at least people get their channels rather than relying on NTL and Chorus to have their full networks (from reception to transmission to reception) in order all the time.

They are definitely allowed to do this, those In The Know tell me. They may take their source from wherever they wish, as long as they have premission from the broadcaster (or if it is off another redistribution platform, that platform's operator) to do so.

I'd imagine that NTL are doing something similar but they'll orobably never admit to it (unless you come across that Ceefax notification page like I did)

Nope - not in Dublin at any rate. For the four UK terrestrials, analogue channels are sourced from analogue, digital channels are sourced from digital. For proof of this, just look at BBC TWO at peak time. On analogue, the pre-programme channel ident will say "BBC TWO", for digital, "BBC TWO NI".

mike65

Well they're at it again! Sometime before the 10 o'clock news on BBC1, text dissapeared, the usual message appeared on P100
and the icon for BBCi appeared on screen.

Maybe its time for an e-mail to you knows whos' office...

Mike.

Frameless

Originally posted by watty
The original MMDS that uses "jerrold" boxes does not have full PAL 8 MHz bandwidth (needed for 6MHz baseband) because it was for lower bandwidth USA 525 Line Vistigial AM signal, rather than the 625 Line European Vistigial Sideband AM. So it struggles with Teletext and is unlikely to manage the Nicam Signal. If Chorus use a baseband video connection, you can't get Nicam anyway without a very expensive Nicam coder (This is why VHS and Digibox are only mono via RF connector and stereo playback needs phono or SCART).

The Pace boxes (all Analog Satellite) is FM. About 25MHz bandwidth, though 16 MHz is possible mod for MMDS to give 6MHz baseband needed. Since only alternate channnels are transmitted on any particular MMDS (11 out of 22) and FM is less suseptable to Co-Channell interference, if the Modulator / MMDS transmitter is changed to FM, yes a Pace Analog box will work (The LNB on the MMDS aerial needs to convert to a different band though).
This would be a lot superior to the original US based "Jerrold" system, if done properly.

What areas are using Analog FM then (Pace boxes)?

DMMDS is in theory a good system, better than channels limited UK DTT.

Is anyone actually arguing they PREFER Analog MMDS (or Analog Cable) to Digital Cable, DMMDS or Sky Digital?
(Admittedly in some Limerick areas cable sufferes a lot from getting "hacked").

It appears like there's some confuion here between transmission standards and what fuction a decoder actually performs. Yes - analogue satellite transmissions are FM and can actually vary in badwidth (the amount of spectrum required for the transmission) between 25 Mhz and 36 Mhz.

A decoder merely has a different tuner installed (for either satellite or terrestrial transmissions received) which it then processes and outputs in the form of an analogue PAL-I signal to the TV via the aerial socket or scart socket.

FYI, all analogue MMDS transmissions are PAL-I in Ireland - regulatory constraints restrict any other forms of transmissions, unless expressly directed by the ODTR. So, ineffect , it is the Jerrold decoder, and not thr transmission medium that provides the problem.

Modified Pace analogue boxes, as used by some Chorus and NTL areas, output not only teletext, but Nicam also, and the Nicam is available via the RF output, which is very convenient for the consumer - no additional wiring. This can be seen (and heard) on the Dublin Cable net.

Indeed, are the so-called 'digital transmissions' merely compressed data on a carrier-wave signal??!! and is not the output of a Sky/Chorus/NTL digibox - you guessed it - an anaolgue PAL-I signal? Finally - FM, if it were to be deployed on analogue terrestrial, would guzzle used. It is used in outer space because of the length of the hop and is way less likely to degrade than an analogue signal in that particular environment.

its

The reason why teletext goes missing on Chorus is simple. They receive the 4 UK channels in Monaghan and transport them to Limerick. Here they reprocess them and distribute them around their network. When they have a fault in their atm network they switch to a standby feed in Limerick. This standby feed is SKY DIGITAL and thats why there is no text. The big question is HOW DID THEY GET UK SKY CARDS in Ireland. Use yor imagination.

watty

Originally posted by Frameless
It appears like there's some confuion here between transmission standards and what fuction a decoder actually performs. Yes - analogue satellite transmissions are FM and can actually vary in badwidth (the amount of spectrum required for the transmission) between 25 Mhz and 36 Mhz.

A decoder merely has a different tuner installed (for either satellite or terrestrial transmissions received) which it then processes and outputs in the form of an analogue PAL-I signal to the TV via the aerial socket or scart socket.

FYI, all analogue MMDS transmissions are PAL-I in Ireland - regulatory constraints restrict any other forms of transmissions, unless expressly directed by the ODTR. So, ineffect , it is the Jerrold decoder, and not thr transmission medium that provides the problem.

Modified Pace analogue boxes, as used by some Chorus and NTL areas, output not only teletext, but Nicam also, and the Nicam is available via the RF output, which is very convenient for the consumer - no additional wiring. This can be seen (and heard) on the Dublin Cable net.

Indeed, are the so-called 'digital transmissions' merely compressed data on a carrier-wave signal??!! and is not the output of a Sky/Chorus/NTL digibox - you guessed it - an anaolgue PAL-I signal? Finally - FM, if it were to be deployed on analogue terrestrial, would guzzle used. It is used in outer space because of the length of the hop and is way less likely to degrade than an analogue signal in that particular environment.

No confusion here.
Pal-I needs almost 6.5MHz baseband to carry the Teletext, Nicam and 6.0 MHz Audio without distortion. Vistigial sideband modulation AM needs 8MHz bandwitdh. The Jerrold boxes are designed for much lower bandwidth NTSC system. I have NO IDEA what is at the the transmitter end, but feeding the CLEAR UNSCRAMBLED channels direct reveals the signal is badly distorted from either of the two channel groups here. The Jerrold box makes the quality worse.

You can modulate PAL-I format Video (6MHz Audio and Nicam subcarrier) on FM with 16MHz Bandwidth. The MMDS uses only alternate of the 22 x 8MHz channels on each transmitter. FM does not have same co-channel interfernce problems...
I don't know what these "Pace" boxes are..
The Only Pace boxes I know about are Either FM Video or MPEG Video.
I'm just suggesting that infact each ANALOG MMDS user could have PAL-I on FM MMDS using regular PACE analog Satellite boxes with 2.5GHz to 1GHz "LNB" or a ADX type box on existing MMDS "LNB" and the whole system would work better with same number of channels. FM is analog. All ANALOG terrestrial Microwave TV links use FM. AM is simple but it isn't very good!

Digital and Compressed are two separate issues.
Actually Digital tranmission systems are:
1) Single Carrier with AM, FM or multisymbol modulation (QAM)
2) Multiple Carrier with AM, FM or multisymbol modulation (QAM)
3) Frequency hopping spread spectrum (low chip rate compared with data rate)
4) Phase modulated spread spectrum (Much higher chip rate than data rate)
5)Time Division Multiplexed Multiple Access (i.e. mobile phones)
6) Code Division Multiplexed Multiple Access(Other mobile phones)
Wierd combinations (i.e. TDMA or CDMA + Spread Spectrum) are possible.
Audio or Video signals may use "lossy" compression prior to transmission. Signals that might be anything may not (Data might compress without error by 2:1, but if the Data is actually Video, Image or sound that algorithm might expand the data!) be compressed or just use some form of LZH coding.
Systems may be error tolerant (Video / audio) or may require retransmisson to ensure no error in a packet.

A digibox converts the MPEG to uncompressed Digital video. This is converted by DAC to RGB (and feeds TV RGB SCART pins). The RGB feeds a cheap (i.e. similar to game console not TV station quality) RGBto PAL coder to feed composite PAL PIN on VHS scart and TV SCART. The sound data stream is MPEG Layer 2 decoded and converted from uncompressed digital to L & R audio by DACs to feed phono and scarts.

The PAL composite (at game console quality not Terrestrial TV PAL-I quality) is fed to a modulator with the L+R added together. The mono sound is modulated to 6.0MHz FM and added to composite PAL (This is what PAL-I is) and modulated to about 470HMz to 890MHz depending on channel.
No set-top box delivers Nicam via the RF outlet nor does any "Nicam" VHS recorder. Nicam is digital system piggy backed on a subcarrier added to the normal Terrestrial transmission. Not part of orignal PAL-I spec. A Nicam coder (from analog dual subcarrier stereo in VHS HiFi recording, Analog Satellite or decoded MPEG Layer2 audio in a digital system is simply too expensive. You won't see one in any household.

All home equipment only delivers stereo by phono, SCART or possibly in a few rare cases SPID (Minidisc, Satellite Receiver or DVD Digital Audio .. not Nicam). Never RF. Only the Terrestrial Broadcasters transmit Nicam.

I'd be extremely surprised if any *ANALOG* MMDS any place has NICAM unless they are frequency shifting from UHF to 2.5GHz channel directly. I'd also be surprised if more than 20% of people in an MMDS transmitter area got a good enough signal even if it was transmitted!


Some people spend 10years learning all this stuff and never stop learning... It isn't simple.

watty

Originally posted by its
The reason why teletext goes missing on Chorus is simple. They receive the 4 UK channels in Monaghan and transport them to Limerick. Here they reprocess them and distribute them around their network. When they have a fault in their atm network they switch to a standby feed in Limerick. This standby feed is SKY DIGITAL and thats why there is no text. The big question is HOW DID THEY GET UK SKY CARDS in Ireland. Use yor imagination.

Perfect explaination.

And when they are not on backup the signal most places is so distorted the pages are half garbled. You should see how much better tletext is on RTE off air good signal, Analog Satellite or Digital Satellite.

Chorus should be told to clean up or get out!

Frameless

Originally posted by watty
No confusion here.
Pal-I needs almost 6.5MHz baseband to carry the Teletext, Nicam and 6.0 MHz Audio without distortion. Vistigial sideband modulation AM needs 8MHz bandwitdh. The Jerrold boxes are designed for much lower bandwidth NTSC system. I have NO IDEA what is at the the transmitter end, but feeding the CLEAR UNSCRAMBLED channels direct reveals the signal is badly distorted from either of the two channel groups here. The Jerrold box makes the quality worse.

You can modulate PAL-I format Video (6MHz Audio and Nicam subcarrier) on FM with 16MHz Bandwidth. The MMDS uses only alternate of the 22 x 8MHz channels on each transmitter. FM does not have same co-channel interfernce problems...
I don't know what these "Pace" boxes are..
The Only Pace boxes I know about are Either FM Video or MPEG Video.
I'm just suggesting that infact each ANALOG MMDS user could have PAL-I on FM MMDS using regular PACE analog Satellite boxes with 2.5GHz to 1GHz "LNB" or a ADX type box on existing MMDS "LNB" and the whole system would work better with same number of channels. FM is analog. All ANALOG terrestrial Microwave TV links use FM. AM is simple but it isn't very good!

Digital and Compressed are two separate issues.
Actually Digital tranmission systems are:
1) Single Carrier with AM, FM or multisymbol modulation (QAM)
2) Multiple Carrier with AM, FM or multisymbol modulation (QAM)
3) Frequency hopping spread spectrum (low chip rate compared with data rate)
4) Phase modulated spread spectrum (Much higher chip rate than data rate)
5)Time Division Multiplexed Multiple Access (i.e. mobile phones)
6) Code Division Multiplexed Multiple Access(Other mobile phones)
Wierd combinations (i.e. TDMA or CDMA + Spread Spectrum) are possible.
Audio or Video signals may use "lossy" compression prior to transmission. Signals that might be anything may not (Data might compress without error by 2:1, but if the Data is actually Video, Image or sound that algorithm might expand the data!) be compressed or just use some form of LZH coding.
Systems may be error tolerant (Video / audio) or may require retransmisson to ensure no error in a packet.

A digibox converts the MPEG to uncompressed Digital video. This is converted by DAC to RGB (and feeds TV RGB SCART pins). The RGB feeds a cheap (i.e. similar to game console not TV station quality) RGBto PAL coder to feed composite PAL PIN on VHS scart and TV SCART. The sound data stream is MPEG Layer 2 decoded and converted from uncompressed digital to L & R audio by DACs to feed phono and scarts.

The PAL composite (at game console quality not Terrestrial TV PAL-I quality) is fed to a modulator with the L+R added together. The mono sound is modulated to 6.0MHz FM and added to composite PAL (This is what PAL-I is) and modulated to about 470HMz to 890MHz depending on channel.
No set-top box delivers Nicam via the RF outlet nor does any "Nicam" VHS recorder. Nicam is digital system piggy backed on a subcarrier added to the normal Terrestrial transmission. Not part of orignal PAL-I spec. A Nicam coder (from analog dual subcarrier stereo in VHS HiFi recording, Analog Satellite or decoded MPEG Layer2 audio in a digital system is simply too expensive. You won't see one in any household.

All home equipment only delivers stereo by phono, SCART or possibly in a few rare cases SPID (Minidisc, Satellite Receiver or DVD Digital Audio .. not Nicam). Never RF. Only the Terrestrial Broadcasters transmit Nicam.

I'd be extremely surprised if any *ANALOG* MMDS any place has NICAM unless they are frequency shifting from UHF to 2.5GHz channel directly. I'd also be surprised if more than 20% of people in an MMDS transmitter area got a good enough signal even if it was transmitted!


Some people spend 10years learning all this stuff and never stop learning... It isn't simple.

A digibox converts the MPEG to uncompressed Digital video. This is converted by DAC to RGB (and feeds TV RGB SCART pins). The RGB feeds a cheap (i.e. similar to game console not TV station quality) RGBto PAL coder to feed composite PAL PIN on VHS scart and TV SCART. The sound data stream is MPEG Layer 2 decoded and converted from uncompressed digital to L & R audio by DACs to feed phono and scarts.




1. So after all that you still end up with an analogue PAL-I signal at the TV socket!

2. The PACE box in question ias a modified PACE PRD-800 satellite receiver which has it's front-end (tuner) replaced to accept analogue MMDS (or cable) transmissions. The box DOES output a modulated RF signal which has a NiCam subcarrier included - thus presenting NiCam at the TV socket. As already mentioned this can be seen (and heard) on the Dublin Cable net.

3. Yes - you're right. There are no current (analogue) MMDS transmitters which transmit NiCam.

4. If MMDS transmitters were modified to transmit a NiCam signal
(and they won't be, due to the current migration to DMMDS) there would be no reason for the NiCam not to work (except on Jerrold boxes) - it's a very robust signal.

I seem to have touched a nerve here. I am not trying to be pro or anti-Sky, Chorus, or NTL - I'm merely trying to present an accurate description of what's actually happening in the MMDS broadcasting field today.

I thought that was the idea of this Forum......

watty

Originally posted by Frameless
The PACE box in question ias a modified PACE PRD-800 satellite receiver which has it's front-end (tuner) replaced to accept analogue MMDS (or cable) transmissions. The box DOES output a modulated RF signal which has a NiCam subcarrier included - thus presenting NiCam at the TV socket. As already mentioned this can be seen (and heard) on the Dublin Cable net.

Yes - you're right. There are no current (analogue) MMDS transmitters which transmit NiCam.

I have repaired PRD800s. Got one here (Or I might have lent it out for ATV reception).

I'd seriously like to see one of these Pace PRD800. What is it connected to?

You could easily fit a TV tuner hardwired for Band III or even connect the BandI/Band III / UHF switch pins to two internal PRD pins that store on a per channel basis. My PRD800 had these buffered by transistors to 12V to select 2nD LNB and automatically operate ADX on a stored channel basis.

You could fit a Cable TV descrambler board instead of the videocrypt card. The analog cable would have to have Nicam already on it. (It doesn't in Limerick)

If it has Nicam on its RF socket and no MMDS transmits Nicam?
(Digital MMDS doesn't use Nicam but MPEG Layer2 audio on a separate data stream). The Pace PRD800 is a strictly FM Analog receiver with a "piggy back" card for videocrypt which can be removed and bypassed. There is no possibility it has a Nicam coder inside so where does the Nicam come from? How do you know it has Nicam on its RF outlet?

Can I see one on my way through someplace travelling Limerick- Dublin?

Fascinated....

I enjoy a healthy discussion....

It would be a bit boring if we all had the same preconvieved ideas, actual knowledge and opinions

Frameless

Originally posted by watty
I have repaired PRD800s. Got one here (Or I might have lent it out for ATV reception).

I'd seriously like to see one of these Pace PRD800. What is it connected to?

You could easily fit a TV tuner hardwired for Band III or even connect the BandI/Band III / UHF switch pins to two internal PRD pins that store on a per channel basis. My PRD800 had these buffered by transistors to 12V to select 2nD LNB and automatically operate ADX on a stored channel basis.

You could fit a Cable TV descrambler board instead of the videocrypt card. The analog cable would have to have Nicam already on it. (It doesn't in Limerick)

If it has Nicam on its RF socket and no MMDS transmits Nicam?
(Digital MMDS doesn't use Nicam but MPEG Layer2 audio on a separate data stream). The Pace PRD800 is a strictly FM Analog receiver with a "piggy back" card for videocrypt which can be removed and bypassed. There is no possibility it has a Nicam coder inside so where does the Nicam come from? How do you know it has Nicam on its RF outlet?

Can I see one on my way through someplace travelling Limerick- Dublin?

Fascinated....

I enjoy a healthy discussion....

It would be a bit boring if we all had the same preconvieved ideas, actual knowledge and opinions

Agreed! They are actually deployed on NTL (old Cablelink) nets since 1994/5 and were manufactured (and modified) by Pace.
The only way you can tell the difference in appearance is, obviously, at the back (normal RF bypass, like on a VCR) and there is no smart card socket behond the drop-down front flap.
Otherwise they are practically identical in appearance.

If you know anyone in Dublin who is an analogue Sky Sports/Movies subscriber you can see them in action. And yes, the minute you switch to the UHF output from the decoder on the TV the NiCam indicator lights up, and the stereo is very defined on the sound section of a NiCam TV. It's just like switching to an RTE off-air feed where the NiCam indicator lights up to indicate a transmission.

Interestingly, the sound from the phono sockets or scart socket is Mono! This can be confirmed with NTL. I don't know how they achieve this without a NiCam encoder, but they're obviously succeeded where other failed.

I suppose it's just more useless information, but it's amazing the amount of stuff that's actually deployed across the diverse range of platforms in Ireland at the moment. All (or the majority) of the analogue basic NTL channels are broadcast in NiCam. It's a very clever trick with the PACE box, as it eleiminates the need for additional audio cables, etc.

Hope that clears it up for you somewhat!

watty

Dunno how they get the Nicam on the Cable. But assuming it is on the cable, the reason the phono is mono is that the Pace has no Nicam decoder. If you feed the receiver "baseband" without filtering into a "video only" RF modulator using the "D2MAC external decoder" baseband mode, then the selected channel's video has the mono 6MHz and the Nicam carrier on it from the original cable signal.

So the only mystery is how NTL managed to inhert bits of cable with FM rather than AM video on them and Nicam.
Chorus for sure arn't going to upgrade any analog cable..