Well, its seemed a pretty short time at the time. I actually only ever had
one set like that as it seemed most mono tvs still used the intercarrier fm
sound originally developed. Brian

--

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"MB" <MB@nospam.net> wrote in message news:tjlkss$3v90$2@dont-email.me...
> On 30/10/2022 09:45, Brian Gaff wrote:
>> Yes I never quite understood Nicam which seemed to have a very short life
>> cycle, coming as it did just before full digital. To be honest my mind
>> tells
>> me that nicam sound actually sounded better than the current sound which
>> seems to be plagued with leaden audio, which sounds like a wider band
>> version of some telephone codecs.
>
>
> NICAM-728 was used for nearly twenty years I think and only ended with
> Digital Switch Over.
>
>
>

On 31/10/2022 09:43, Brian Gaff wrote:
> Not only that but the of stages of tuners were and maybe still are affected
> by the adjacent channel being strong, either desensing the set or
> intermodulation effects in the rf stages. Obviously they tried not to use
> Adjacent channels, but often you could get another region almost as strongly
> as yours. Brian
>
Adjacent channel working is a perquisite for DVB-T, it had to be, in
order to accommodate six or more muxes per transmitter, in a broadcast
band that now only runs from Ch 21 to 48

Caldbeck has 8 muxes all in a block from 21-28

In article <js73liFhcr4U2@mid.individual.net>, Mark Carver
<mark.carver@invalid.invalid> wrote:

> >
> NICAM was used internally by the Beeb from the early 80s (it replaced
> the linear PCM streams on their national radio distribution)

https://www.audiomisc.co.uk/BBC/PCMandNICAM/History.html
https://www.audiomisc.co.uk/BBC/FMandNICAM3/FMandNICAM3.html

--
Please use the address on the audiomisc page if you wish to email me.
Electronics https://www.st-andrews.ac.uk/~www_pa/Scots_Guide/intro/electron.htm
biog http://jcgl.orpheusweb.co.uk/history/ups_and_downs.html
Audio Misc http://www.audiomisc.co.uk/index.html

Which is probably why it sounded better in most cases. The clever bit for me
was the near instantaneous part, which is hardly what current digital
formats offer. It had to be that way one imagines so that it was in step
with the analogue pictures.
Brian

--

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"Jim Lesurf" <noise@audiomisc.co.uk> wrote in message
news:5a3f6fdc3dnoise@audiomisc.co.uk...
> In article <20221029185426.f45b47e35be4196c0e590d50@gmail.com>,
> pinnerite
> <pinnerite@gmail.com> wrote:
>> I took courses in colour TV during the middle to late sixties. I
>> understood Walter Bruch's PAL system and our 625 line variant.
>
>> But I honestly never troubled to find out how our digital TV system
>> works.
>
>> Can someone point me to a sort of "UK Digital TV for geriatrics" that
>> might be helpful?
>
>> TIA, Alan
>
> Try books by John Watkinson.
>
> Jim
>
> --
> Please use the address on the audiomisc page if you wish to email me.
> Electronics
> https://www.st-andrews.ac.uk/~www_pa/Scots_Guide/intro/electron.htm
> biog http://jcgl.orpheusweb.co.uk/history/ups_and_downs.html
> Audio Misc http://www.audiomisc.co.uk/index.html
>

On Monday, 31 October 2022 at 09:57:33 UTC, Mark Carver wrote:

> Caldbeck has 8 muxes all in a block from 21-28
I still can't figure how the electrons know what they're supposed to be doing. Don't they get confused?
Bill

On Sunday, 30 October 2022 at 18:10:34 UTC, Andy Burns wrote:
> David Woolley wrote:
>
> > So called LED TVs are actually LED (as against cold cathode) backlit LCD ones.
> Apart from OLED TVs.

Every OLED is an LED, but not every LED is an OLED!

On 30/10/2022 10:21, Andy Burns wrote:
> Apart from OLED TVs.

Generally OLED TVs are marketed as OLED, not as LED, so LED TV tends to
be reserved for LED backlighting, rather than LEDs as the active emitter.

On 31/10/2022 09:56, Brian Gaff wrote:
> Well, its seemed a pretty short time at the time. I actually only ever had
> one set like that as it seemed most mono tvs still used the intercarrier fm
> sound originally developed. Brian

My first two tellies just reproduced FM (mono) sound through a pathetic
amplifier and speaker.

My VCR could be switched so the sound out of the phono plugs to my hifi
was either the FM sound or the NICAM sound when tuned to an off-air
channel (when playing back a recording, the same menu item switched
between linear and hifi sound on the tape).

There was a noticeable difference in sound quality between FM and NICAM
- and that's ignoring the rather obvious difference between mono and
stereo. The difference between linear and hifi sound on a tape was even
more obvious.

The only time I ever set the VCR to reproduce the linear tape soundtrack
was when I was digitising a tape that had damage to the hifi soundtrack,
and linear soundtrack with tape hiss was preferable to hifi sound which
kept dropping out.

On Mon, 31 Oct 2022 08:22:37 -0700 (PDT), "wrightsaerials@aol.com"
<wrightsaerials@f2s.com> wrote:

>On Monday, 31 October 2022 at 09:57:33 UTC, Mark Carver wrote:
>
>> Caldbeck has 8 muxes all in a block from 21-28
>I still can't figure how the electrons know what they're supposed to be doing. Don't they get confused?

Surely you mean photns. Traveling at speed of light they are
everywhere all the time.

--
brightside S9

On 31/10/2022 09:57, Mark Carver wrote:
> On 31/10/2022 09:43, Brian Gaff wrote:
>> Not only that but the of stages of tuners were and maybe still are
>> affected
>> by the adjacent channel being strong, either desensing the set or
>> intermodulation effects in the rf stages. Obviously they tried not to use
>> Adjacent channels, but often you could get another region almost as
>> strongly
>> as yours. Brian
>>
> Adjacent channel working is a perquisite for DVB-T, it had to be, in
> order to accommodate six or more muxes per transmitter, in a broadcast
> band that now only runs from Ch 21 to 48
>
> Caldbeck has 8 muxes all in a block from 21-28

Was a spacing of three UHF channels (eg 60 and 63) the smallest that was
used between two stations on same transmitter in analogue days, or did
some transmitters use a spacing of two (eg 60 and 62).

Could the tuners on analogue TVs that we made around the time of DSO
have tolerated adjacent UHF channels? Or were even "modern" tuners
unable to reject adjacent-channel signals.

Nowadays, as you say, some digital muxes are on adjacent channels, and
no-one bats an eyelid at that.

How good is digital at rejecting a weaker signal from a distant
transmitter than happens to be on the same channel as a stronger signal
from the normal transmitter? Is it co-channel interference that tends to
cause an increase in glitches at times of abnormal propagation, or are
glitches normally due to some muxes being weaker than normal and
therefore having poorer SNR? (I'm distinguishing between random noise
and weak but discernable digital signal).

On Monday, 31 October 2022 at 23:59:36 UTC, BrightsideS9 wrote:
> On Mon, 31 Oct 2022 08:22:37 -0700 (PDT), "wrights...@aol.com"
> <wrights...@f2s.com> wrote:
>
> >On Monday, 31 October 2022 at 09:57:33 UTC, Mark Carver wrote:
> >
> >> Caldbeck has 8 muxes all in a block from 21-28
> >I still can't figure how the electrons know what they're supposed to be doing. Don't they get confused?
> Surely you mean photns. Traveling at speed of light they are
> everywhere all the time.

No I meant the electrons in the coax. All that jiggling about, yet when you press your ear against an aerial downlead you can't hear a thing.
Bill

On 01/11/2022 00:07, NY wrote:
> On 31/10/2022 09:57, Mark Carver wrote:
>> On 31/10/2022 09:43, Brian Gaff wrote:
>>> Not only that but the of stages of tuners were and maybe still are
>>> affected
>>> by the adjacent channel being strong, either desensing the set or
>>> intermodulation effects in the rf stages. Obviously they tried not
>>> to use
>>> Adjacent channels, but often you could get another region almost as
>>> strongly
>>> as yours. Brian
>>>
>> Adjacent channel working is a perquisite for DVB-T, it had to be, in
>> order to accommodate six or more muxes per transmitter, in a
>> broadcast band that now only runs from Ch 21 to 48
>>
>> Caldbeck has 8 muxes all in a block from 21-28
>
> Was a spacing of three UHF channels (eg 60 and 63) the smallest that
> was used between two stations on same transmitter in analogue days, or
> did some transmitters use a spacing of two (eg 60 and 62).

The usual pattern was 3-3-3-4  or 4-3-3-3.  Spacings of 9 and 5 channels
were taboo, because of  local oscillator images. Not that that stopped
C5 breaking the rule in a number of locations (Ch 37 and 46)

Some relays (Newhaven springs to mind) had spacings of 2. 39-41-43-45

>
> Could the tuners on analogue TVs that we made around the time of DSO
> have tolerated adjacent UHF channels? Or were even "modern" tuners
> unable to reject adjacent-channel signals.

Possibly, modern DSP tuners can perform miracles !  My car radio can
separate FM stations that are 100 kHz apart, provided they are of
similar level

> How good is digital at rejecting a weaker signal from a distant
> transmitter than happens to be on the same channel as a stronger
> signal from the normal transmitter? Is it co-channel interference that
> tends to cause an increase in glitches at times of abnormal
> propagation, or are glitches normally due to some muxes being weaker
> than normal and therefore having poorer SNR? (I'm distinguishing
> between random noise and weak but discernable digital signal).

Any signal that a digital receiver can't identify as vaild, is
effectively random noise. That includes SFN transmissions that fall
outside the timing window.  The protection ratios are lower for DVB-T
but it depends on the parameters. QPSK  (aka 4QAM) (as used for local TV
muxes) is more robust than 64QAM

On Mon, 31 Oct 2022 23:55:09 +0000, NY <me@privacy.net> wrote:

>There was a noticeable difference in sound quality between FM and NICAM
>- and that's ignoring the rather obvious difference between mono and
>stereo.

I built a Maplin kit which was a standalone receiver with audio and
video outputs, and front panel switches to select either NICAM or FM
sound. There were also internal pots to adjust audio levels so they
could match exactly between the two systems, and the switch was simply
a mechanical one that selected the two constantly available feeds from
the two decoders, so that they could be compared instantly without any
pauses or glitches. When listening to a mono programme, or with the
NICAM output switched to mono, the only difference I could hear was
that FM had background hiss and NICAM didn't. It was as if the switch
was simply turning the hiss on and off, and it was quite a surprise
how much hiss I had previously been content to endure.

We're spoilt with today's digital audio systems. With nothing playing
on whatever source is selected (internet streamer, disc player etc), I
can turn the volume control on my amplifier the full 270deg to maximum
(it's normally around 60deg for most programme material) and still
hear total silence even if I stick my head up close directly in front
of one of the speakers. There's no hiss or hum, no clicks or pops, no
dialing pulses, no clanking valve electrodes or any of the other
extraneous sounds that were the bane of my life when I was building
hi-fi equipment in my teenage years. There's nothing at all when
nothing is playing, which is just as it should be.

Rod.

On Tuesday, 1 November 2022 at 00:07:18 UTC, NY wrote:
> On 31/10/2022 09:57, Mark Carver wrote:
> > On 31/10/2022 09:43, Brian Gaff wrote:
> >> Not only that but the of stages of tuners were and maybe still are
> >> affected
> >> by the adjacent channel being strong, either desensing the set or
> >> intermodulation effects in the rf stages. Obviously they tried not to use
> >> Adjacent channels, but often you could get another region almost as
> >> strongly
> >> as yours. Brian
> >>
> > Adjacent channel working is a perquisite for DVB-T, it had to be, in
> > order to accommodate six or more muxes per transmitter, in a broadcast
> > band that now only runs from Ch 21 to 48
> >
> > Caldbeck has 8 muxes all in a block from 21-28
> Was a spacing of three UHF channels (eg 60 and 63) the smallest that was
> used between two stations on same transmitter in analogue days, or did
> some transmitters use a spacing of two (eg 60 and 62).
>
> Could the tuners on analogue TVs that we made around the time of DSO
> have tolerated adjacent UHF channels? Or were even "modern" tuners
> unable to reject adjacent-channel signals.
>
> Nowadays, as you say, some digital muxes are on adjacent channels, and
> no-one bats an eyelid at that.
>
> How good is digital at rejecting a weaker signal from a distant
> transmitter than happens to be on the same channel as a stronger signal
> from the normal transmitter? Is it co-channel interference that tends to
> cause an increase in glitches at times of abnormal propagation, or are
> glitches normally due to some muxes being weaker than normal and
> therefore having poorer SNR? (I'm distinguishing between random noise
> and weak but discernable digital signal).

The Luma (black and white) signal on PAL was AM, so co and adjacent channel interference were a big problem so transmitters on the same channel had to be far apart and transponders well separated.

This applies much less to FM (FM capture eliminates co channel interference) and digital. Indeed on satellite the channels overlap, but alternate ones are polarised horizontal and vertical and on adjacent satellite the pattern is reversed.

On Tuesday, 1 November 2022 at 02:01:54 UTC, wrightsaerials@aol.com wrote:
> On Monday, 31 October 2022 at 23:59:36 UTC, BrightsideS9 wrote:
> > On Mon, 31 Oct 2022 08:22:37 -0700 (PDT), "wrights...@aol.com"
> > <wrights...@f2s.com> wrote:
> >
> > >On Monday, 31 October 2022 at 09:57:33 UTC, Mark Carver wrote:
> > >
> > >> Caldbeck has 8 muxes all in a block from 21-28
> > >I still can't figure how the electrons know what they're supposed to be doing. Don't they get confused?
> > Surely you mean photns. Traveling at speed of light they are
> > everywhere all the time.
> No I meant the electrons in the coax. All that jiggling about, yet when you press your ear against an aerial downlead you can't hear a thing.
> Bill

Ears are not electromagnetic.

"R. Mark Clayton" <notyalckram@gmail.com> wrote in message
news:88abee71-93c9-4ec9-af9d-2ba74cf95246n@googlegroups.com...
> Indeed on satellite the channels overlap, but alternate ones are polarised
> horizontal and vertical and on adjacent satellite the pattern is reversed.

I've always wondered how a few satellite muxes (eg 11306 H/V) are on the
same frequency and distinguished only by polarisation, when most
transponders are separated both by frequency and polarisation. I imagine the
"duplicate" frequencies are actually very slightly different, but evidently
much more similar than normal.

On 01/11/2022 12:13, R. Mark Clayton wrote:
> The Luma (black and white) signal on PAL was AM
The chroma was also a derivative of AM.

Strictly speaking, the luma was vestigial sideband and the chroma was
double sideband suppressed carrier, on a sub-carrier.

On 01/11/2022 12:39, NY wrote:
> I imagine the "duplicate" frequencies are actually very slightly
> different, but evidently much more similar than normal.

I don't think enough spectrum is spare between channels for that. I
think it is simply a matter that the receiving dish has to be more
accurately aligned, to reject the other polarisation.

On 01/11/2022 12:13, R. Mark Clayton wrote:
> Ears are not electromagnetic.

I could "hear" the VLF pulses from the OMEGA transmitter at Criggion
when we visited (many years ago) and went in the coil chamber.

In article <tjr6p9$pm1g$1@dont-email.me>, NY <me@privacy.invalid> wrote:
> "R. Mark Clayton" <notyalckram@gmail.com> wrote in message
> news:88abee71-93c9-4ec9-af9d-2ba74cf95246n@googlegroups.com...
> > Indeed on satellite the channels overlap, but alternate ones are
> > polarised horizontal and vertical and on adjacent satellite the
> > pattern is reversed.

> I've always wondered how a few satellite muxes (eg 11306 H/V) are on the
> same frequency and distinguished only by polarisation, when most
> transponders are separated both by frequency and polarisation. I imagine
> the "duplicate" frequencies are actually very slightly different, but
> evidently much more similar than normal.

Sattelite reception uses a much more directional aerial (dish) than
terrestrial reception. Terrestrial reception is also prone to polarization
chages due to reflections of buildings, etc.

--
from KT24 in Surrey, England - sent from my RISC OS 4té
"I'd rather die of exhaustion than die of boredom" Thomas Carlyle

In article <33d0f2d0-ed35-4e2c-9d66-64b50171fe4fn@googlegroups.com>,
wrightsaerials@aol.com <wrightsaerials@f2s.com> wrote:
> On Monday, 31 October 2022 at 09:57:33 UTC, Mark Carver wrote:

> > Caldbeck has 8 muxes all in a block from 21-28
> I still can't figure how the electrons know what they're supposed to be
> doing. Don't they get confused? Bill

Yes. That's why they are fuzzy and aren't precisely located. The confusion
of elementary particles is the basis of QM.

Jim

--
Please use the address on the audiomisc page if you wish to email me.
Electronics https://www.st-andrews.ac.uk/~www_pa/Scots_Guide/intro/electron.htm
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Audio Misc http://www.audiomisc.co.uk/index.html

In article <77o0mhhtnu3cjdmsenecp2qnj87i4s9i70@4ax.com>, BrightsideS9
<reply_to_address_is_not@invalid.invalid> wrote:

> Surely you mean photns. Traveling at speed of light they are everywhere
> all the time.

They don't really 'travel' at that speed. It is just that the time it takes
to work out where to be when they move depends linarly on what we see as
the distance between emission and collapse.

Jim

--
Please use the address on the audiomisc page if you wish to email me.
Electronics https://www.st-andrews.ac.uk/~www_pa/Scots_Guide/intro/electron.htm
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Audio Misc http://www.audiomisc.co.uk/index.html

On Tuesday, 1 November 2022 at 13:40:55 UTC, David Woolley wrote:
> On 01/11/2022 12:39, NY wrote:
> > I imagine the "duplicate" frequencies are actually very slightly
> > different, but evidently much more similar than normal.
> I don't think enough spectrum is spare between channels for that. I
> think it is simply a matter that the receiving dish has to be more
> accurately aligned, to reject the other polarisation.
If you're talking about signals from adjacent satellites, yes it can be a problem. Sometimes it explains why some muxes are poor when others are good. Better dish alignment or a bigger dish is usually the answer.
Bill

On Tuesday, 1 November 2022 at 12:13:59 UTC, R. Mark Clayton wrote:

> > No I meant the electrons in the coax. All that jiggling about, yet when you press your ear against an aerial downlead you can't hear a thing.
> > Bill
> Ears are not electromagnetic.
Ears aren't hydraulic but I can hear the water in a pipe.
Bill

On 01/11/2022 19:06, wrightsaerials@aol.com wrote:
> Ears aren't hydraulic but I can hear the water in a pipe.
> Bill

True!

I wondered at the time if we were 'hearing' resonances in various bits
of metal around the room.