Post-Switchover Mux Allocations

"Andy Wade" wrote...

Yes, the change from 16-QAM rate 3/4 to 64-QAM rate 2/3 is worth
about -4 dB, but you should also include the effective gain from the
change from 2K mode to 8K, which is ~+6 dB (since it's impulsive
interference that sets the minimum usable signal level in practice).
Overall gain then ~+14 dB in this case.

I'd love to understand your comments about the relationship between
impulsive interference and signal levels. Could you expand a bit?

Matti

In message , Gladys Pugh
writes
Don't start me on HTV Wales or whatever it's called this week,
Going back a lot of years, I can remember getting BBC from Wenvoe and
TWW(south Wales and the West) from St. Hilary's, nobody in Bristol was
very happy with all the enforced Welsh language.
--
Clive.

On Fri, 16 Nov 2007 23:17:09 -0000, "Gladys Pugh"
wrote:

Marky P wrote:
From what I hear, it sounds as if most people in Wales don't like
Welsh TV? I thought the Welsh were very patriotic and hated
anything to do with the English.

The problem is that the clique who run BBC Wales
are utterly OBSESSED with the Welsh language and rugby,
despite the fact that 80% of people in Wales (in the 2001 census)
have little or no knowledge of the Welsh language, and my guess
is that a similar proportion don't play rugby.

You wouldn't believe how often the lead story on Wales Today
is about rugby - if a rugby player sneezes there'll be a whole
feature item on the poor dab!

And then there are all the rugby trailers between programmes,
network trailers are rarely aired in Wales.

Don't start me on HTV Wales or whatever it's called this week,
totally amateurish with some embarrassingly awful simpering
female presenters. Only good for a laugh!

Little wonder $ky has massive take-up in the Valleys.




I installed DTT at my friends holiday home in Ilfracombe, Devon, and
Wenvoe was my only choice. My neice and her husband stayed down there
for a week and were quite puzzled by the Welsh TV reception. In 2009,
I'll have to go down there and retune everything to the Ilfracombe
relay when DSO happens. I'll still use Wenvoe for the COM muxes.

Marky P.

Clive wrote:
Don't start me on HTV Wales or whatever it's called this week,
Going back a lot of years, I can remember getting BBC from Wenvoe
and TWW(south Wales and the West) from St. Hilary

Hey, I grew-up with TWW.
http://625.uk.com/tv_logos/flash/tww_channel_10.asp

Compared to the present lot they were highly professional
and their newsreaders delivered the news in a personable
yet authoritative manner.
Also, friendly announcers popping-up in vision between
the programmes - they felt like members of the family!

I've been using the Humax PVR-9200T's system menu to check the signal
levels on the channels I usually watch, and noticed something
interesting which gave me A Thought.

Mux 2 on Mendip channel 55 746MHz consistently gives a significantly
higher level (typically 67%) then the other five muxes (all typically
60%), so if the channels on that mux have a lower incidence of the
breakup problem it would seem to suggest that a 10% signal increase
overall would be useful, possibly more so than attempting to reduce
interference levels.

Mux A on Mendip channel 62 802MHz has a similar digital structure in
terms of QAM, so what I thought I'd do is to use the Humax's twin tuners
to record a couple of hours of a Mux 2 channel (itv3) and simultaneously
of a Mux A channel (five Life). Then I'd compare breakup incidence on
the two recordings.

Is this likely to produce something useful, or is my proposed experiment
seriously flawed?

Matti

On Fri, 16 Nov 2007 22:47:43 +0000 (GMT), charles
wrote:

In article ,
Marky P wrote:
On Thu, 15 Nov 2007 17:30:45 -0000, "Doctor D"
wrote:



Actually Wenvoe isn't too good at the hotel either. I once 20+ years
ago had to go and look for BBC Wales signals since the BBC Welsh
Governors were due to have a meeting there. From the photos the
building seems much larger now than it was then, so perhaps they can
now get decent signal with a rooftop aerial.

Speaking as a Welshman, I suspect they are one of the few groups of
people who would prefer Welsh TV.

I stayed at the Angel Hotel in Cardiff three years ago and was dismayed
to find I had the choice of only 4 channels, one of which was in Welsh!
I'm not a big TV watcher, but the hotel is so noisy that I hardly slept.
A radio or some extra TV channels would have been nice. If you have to
stay here, insist on a room at the back, and take ear plugs.

From what I hear, it sounds as if most people in Wales don't like Welsh
TV? I thought the Welsh were very patriotic and hated anything to do
with the English. Have things changed? I like Wales and Welsh people.
Never understood the point of hating people you don't know.

Many years ago, a Welsh clergyman said to me - at the time when BBC Wales
showed a locally made programme instead of the Commonwealth Games, where
Welsh athletes were winning medals - "After all, my congregation do
understand English.". It isn't that the Welsh don't want programmes in
Welsh, they don't like to miss out on the English ones.

Just like when, as an outsider approaching a group in conversation,
they revert to jabbering Welsh until they think you are out of
earshot, at which point they revert to perfect English. Quite
amusing when the wind blows the conversation downwind or even better
the person you are walking with has a good working knowledge of Welsh.


--

In message , Mike
writes

On Fri, 16 Nov 2007 22:47:43 +0000 (GMT), charles
wrote:

In article ,
Marky P wrote:
On Thu, 15 Nov 2007 17:30:45 -0000, "Doctor D"
wrote:



Actually Wenvoe isn't too good at the hotel either. I once 20+ years
ago had to go and look for BBC Wales signals since the BBC Welsh
Governors were due to have a meeting there. From the photos the
building seems much larger now than it was then, so perhaps they can
now get decent signal with a rooftop aerial.

Speaking as a Welshman, I suspect they are one of the few groups of
people who would prefer Welsh TV.

I stayed at the Angel Hotel in Cardiff three years ago and was dismayed
to find I had the choice of only 4 channels, one of which was in Welsh!
I'm not a big TV watcher, but the hotel is so noisy that I hardly slept.
A radio or some extra TV channels would have been nice. If you have to
stay here, insist on a room at the back, and take ear plugs.

From what I hear, it sounds as if most people in Wales don't like Welsh
TV? I thought the Welsh were very patriotic and hated anything to do
with the English. Have things changed? I like Wales and Welsh people.
Never understood the point of hating people you don't know.

Many years ago, a Welsh clergyman said to me - at the time when BBC Wales
showed a locally made programme instead of the Commonwealth Games, where
Welsh athletes were winning medals - "After all, my congregation do
understand English.". It isn't that the Welsh don't want programmes in
Welsh, they don't like to miss out on the English ones.

Just like when, as an outsider approaching a group in conversation,
they revert to jabbering Welsh until they think you are out of
earshot, at which point they revert to perfect English. Quite
amusing when the wind blows the conversation downwind or even better
the person you are walking with has a good working knowledge of Welsh.


Many years ago (1975?), a works colleague and I were on a business trip
to Treorchy, and we had to spend a couple of nights there. In the
evening, we dined in a pub ('chicken in a basket', I recall!). The TV
was on BBC1. A new programme started with the announcement "This is BBC
TV Wales, Teleweli Cymru", and proceeded in the Welsh language. Almost
in unison, the locals at the bar cried (in broad Welsh accents) "Oh
bloody 'ell!", and switched over to ITV. I've never forgotten this.
--
Ian

On Tue, 20 Nov 2007 23:26:14 +0000, Ian Jackson
wrote:

In message , Mike
writes

On Fri, 16 Nov 2007 22:47:43 +0000 (GMT), charles
wrote:

In article ,
Marky P wrote:
On Thu, 15 Nov 2007 17:30:45 -0000, "Doctor D"
wrote:



Actually Wenvoe isn't too good at the hotel either. I once 20+ years
ago had to go and look for BBC Wales signals since the BBC Welsh
Governors were due to have a meeting there. From the photos the
building seems much larger now than it was then, so perhaps they can
now get decent signal with a rooftop aerial.

Speaking as a Welshman, I suspect they are one of the few groups of
people who would prefer Welsh TV.

I stayed at the Angel Hotel in Cardiff three years ago and was dismayed
to find I had the choice of only 4 channels, one of which was in Welsh!
I'm not a big TV watcher, but the hotel is so noisy that I hardly slept.
A radio or some extra TV channels would have been nice. If you have to
stay here, insist on a room at the back, and take ear plugs.

From what I hear, it sounds as if most people in Wales don't like Welsh
TV? I thought the Welsh were very patriotic and hated anything to do
with the English. Have things changed? I like Wales and Welsh people.
Never understood the point of hating people you don't know.

Many years ago, a Welsh clergyman said to me - at the time when BBC Wales
showed a locally made programme instead of the Commonwealth Games, where
Welsh athletes were winning medals - "After all, my congregation do
understand English.". It isn't that the Welsh don't want programmes in
Welsh, they don't like to miss out on the English ones.

Just like when, as an outsider approaching a group in conversation,
they revert to jabbering Welsh until they think you are out of
earshot, at which point they revert to perfect English. Quite
amusing when the wind blows the conversation downwind or even better
the person you are walking with has a good working knowledge of Welsh.


Many years ago (1975?), a works colleague and I were on a business trip
to Treorchy, and we had to spend a couple of nights there. In the
evening, we dined in a pub ('chicken in a basket', I recall!). The TV
was on BBC1. A new programme started with the announcement "This is BBC
TV Wales, Teleweli Cymru", and proceeded in the Welsh language. Almost
in unison, the locals at the bar cried (in broad Welsh accents) "Oh
bloody 'ell!", and switched over to ITV. I've never forgotten this.

The Welsh language exists so they can **** of the English. The truth
be told, they probably haven't a clue what they are saying either!

Marky P.

Matti Lamprhey wrote:

I'd love to understand your comments about the relationship between
impulsive interference and signal levels. Could you expand a bit?

You mean the bit where I said "since it's impulsive interference that
sets the minimum usable signal level in practice"?

What it says, really. Ignoring impulsive interference (II) you can
easily work out the minimum signal level required on thermal noise
grounds if you know the system parameters. The noise floor (kTB) in a
7.6 MHz bandwidth is just under 4 dBuV[*] in 75 ohms, C/N required for
64-QAM is a little under 20 dB (for a multipath-free channel), and the
receiver noise figure will be around 6-8 dB. Add those together gives
you a minimum (cliff-edge) signal level in the low-30s of dBuV (~ -80
dBm), or the mid-30s if you allow some margin for fading, etc.

In practice installations working with 40dBuV at the tuner input will
suffer break-up from II to some extent, unless the aerial system is of a
very high standard and isn't looking across a road, etc. In the early
days of DTT it was soon established that a minimum level of around 45
dBuV at the receiver input is needed to give solid reception, or higher
if the aerial installation is of a poor standard.

You'll find more info in the DTG 'R-Books' available from
http://www.dtg.org.uk/publications/books.html

--
Andy

"Andy Wade" wrote...
Matti Lamprhey wrote:

I'd love to understand your comments about the relationship between
impulsive interference and signal levels. Could you expand a bit?

You mean the bit where I said "since it's impulsive interference that
sets the minimum usable signal level in practice"?

What it says, really. Ignoring impulsive interference (II) you can
easily work out the minimum signal level required on thermal noise
grounds if you know the system parameters. [...]

You'll find more info in the DTG 'R-Books' available from
http://www.dtg.org.uk/publications/books.html

Many thanks!

Matti