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uk.tech.digital-tv (Digital TV - General) (uk.tech.digital-tv) Discussion of all matters technical in origin related to the reception of digital television transmissions, be they via satellite, terrestrial or cable. Advertising is forbidden, with no exceptions.

Problems today with muxes 7 and 8



 
 
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  #11  
Old January 25th 18, 07:39 PM posted to uk.tech.digital-tv
Bill Wright[_3_]
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Posts: 2,448
Default Problems today with muxes 7 and 8

They've fixed it now.

Bill
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  #12  
Old January 25th 18, 08:00 PM posted to uk.tech.digital-tv
Andy Burns[_12_]
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Posts: 573
Default Problems today with muxes 7 and 8

Woody wrote:

Don't I remember something about Sony's having problems when another
component of DTTV changed some years ago?


Some of the early sony's didn't support 8k carrier mode, so couldn't
receive after DSO when 2k carriers were discontinued.

  #13  
Old January 25th 18, 08:30 PM posted to uk.tech.digital-tv
Graham.[_12_]
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Default Problems today with muxes 7 and 8

Woody wrote:

Don't I remember something about Sony's having problems when another
component of DTTV changed some years ago?


Some of the early sony's didn't support 8k carrier mode, so couldn't
receive after DSO when 2k carriers were discontinued.


My Vestel PVRs could not cope when Winter Hill put a -167KHz some of
its MUXs. I was lucky enough to find a firmware upgrade (via this
group) and had the wherewithal to apply it. I imagine many boxes just
went to landfill at that point.

Then there was the split Network Information Table debacle.

--

Graham.
%Profound_observation%
  #14  
Old January 25th 18, 10:56 PM posted to uk.tech.digital-tv
NY
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Posts: 1,329
Default Problems today with muxes 7 and 8

"Bill Wright" wrote in message
news
Today the GI was increased from 1/128 to 1/16 on muxes 7 and 8. GI is
guard interval. It’s been increased today from 1/128 to 1/16 so they can
operate single frequency networks because of the shortage of channels
starting in March when we lose channels above 49. It appears that some but
not all Sonys are now blind to mux 7 and there are also problems with some
Panasonics. Thanks Mark Carver for some of this info.


You've prompted me to check my PCTV 292e USB device that I use for recording
on my PC - and it seems to be happy with BBC Four HD. I'll try my parents'
TV at their holiday cottage when I go there on Saturday - that's the only
other DVB-T2 device that I know of. Not sure what make it is. At least both
here and the cottage are Bilsdale, so there isn't the additional Emley
problem.

Presumably the SFN will require the whole country to retune, unless the new
national frequencies for COM7 and 8 happen to be the frequencies that some
transmitters are currently using. Interesting that it's not in the Changes
to Come section of http://www.a516digital.com/p/freeview-updates.html

  #15  
Old January 26th 18, 06:19 AM posted to uk.tech.digital-tv
Mark Carver[_2_]
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Posts: 439
Default Problems today with muxes 7 and 8

On 25/01/2018 21:30, Graham. wrote:
Woody wrote:

Don't I remember something about Sony's having problems when another
component of DTTV changed some years ago?


Some of the early sony's didn't support 8k carrier mode, so couldn't
receive after DSO when 2k carriers were discontinued.


My Vestel PVRs could not cope when Winter Hill put a -167KHz some of
its MUXs. I was lucky enough to find a firmware upgrade (via this
group) and had the wherewithal to apply it. I imagine many boxes just
went to landfill at that point.

Then there was the split Network Information Table debacle.


Yes! The receivers that were untroubled by that were the OnDigital
boxes, fully compliant. Of course they were only 2k capable, so
they effectively died at DSO.

Another by-product of COM7/8 being configured as national SFNs,
is now their SI tables are huge, because they have to cross refer
every regional variation on all the muxes they overlap with nationally
(plus all the local muxes). That might well be slowing some receivers down.



--
Mark
Please replace invalid and invalid with gmx and net to reply.
  #16  
Old January 26th 18, 06:27 AM posted to uk.tech.digital-tv
Mark Carver[_2_]
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Default Problems today with muxes 7 and 8

On 25/01/2018 23:56, NY wrote:

Presumably the SFN will require the whole country to retune,


Yes, but not all at once, the 700 MHz changes are phased.

First two sites to move COM 7 to 55 are Mendip and Waltham next month,
and even then COM 8 won't move until later. At Mendip COM 7 swaps with
COM 4.

Crystal P is moving 7 and 8 in March, some other sites not until 2019 or
2020.
Of course in parallel with this is about 75% of all transmitters having
at least one of the main muxes move, as the top of the UHF band is
cleared.

Loads of retuning ahead !

unless the
new national frequencies for COM7 and 8 happen to be the frequencies
that some transmitters are currently using.


See Mendip, but you will still need to retune, because the SI etc as
received on the mux will change.

Interesting that it's not in
the Changes to Come section of
http://www.a516digital.com/p/freeview-updates.html


You're looking in the wrong part of that site

http://www.a516digital.com/2017/11/f...where-and.html


--
Mark
Please replace invalid and invalid with gmx and net to reply.
  #17  
Old January 26th 18, 07:38 AM posted to uk.tech.digital-tv
Woody[_5_]
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Default Problems today with muxes 7 and 8


"Andy Burns" wrote in message
...
Woody wrote:

Don't I remember something about Sony's having problems when
another
component of DTTV changed some years ago?


Some of the early sony's didn't support 8k carrier mode, so couldn't
receive after DSO when 2k carriers were discontinued.



There was that and the NIT, but having slept on it ISTR it was
something to do with Ch4 analogue with Sony TVs maybe 10 years ago?


--
Woody

harrogate3 at ntlworld dot com


  #18  
Old January 26th 18, 07:52 AM posted to uk.tech.digital-tv
Mark Carver[_2_]
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Posts: 439
Default Problems today with muxes 7 and 8

On 26/01/2018 08:38, Woody wrote:

There was that and the NIT, but having slept on it ISTR it was
something to do with Ch4 analogue with Sony TVs maybe 10 years ago?


Yes, but 20 years ago ! When C4 adopted PAL+ in 1994, part of that was
the requirement to have widescreen signalling on VBI line 23.

On widescreen sets, this was to enable 'zoom' mode to fill the screen
on 16:9 letterbox material. That was fine, however for 4:3 transmissions
Sonys decoded the 4:3 WSS ident as a command to go into
that horrible non linear 'Smart Zoom' mode.
There was nothing much that could be done, as it was
more or less hard coded into the electronics, the only cure was for
C4 not to carry any WSS ident during 4:3 programming, and the affected
Sonys would then just sit in 4:3 mode. (C4 didn't do that, arguing
quite rightly it was Sony's problem, not theirs)

It also caused the same problem once DTT/D-Sat started, and some boxes
would use the L23 WSS commands.



--
Mark
Please replace invalid and invalid with gmx and net to reply.
  #19  
Old January 26th 18, 07:53 AM posted to uk.tech.digital-tv
NY
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Posts: 1,329
Default Problems today with muxes 7 and 8

"Mark Carver" wrote in message
...
On 25/01/2018 23:56, NY wrote:

Presumably the SFN will require the whole country to retune,


Yes, but not all at once, the 700 MHz changes are phased.


Ah, so in the interim some transmitters will change to the national SFN
frequencies for COM7/8 and others will keep their existing frequencies and
will change later to the national frequencies? I'd assumed that the SFN
would not come into effect until all transmitters (that broadcast COM7/8)
throughout the UK had changed. I presume that as transmitters join the
national frequencies, they get locked in frequency and phase to the master,
so as to make a true SFN as opposed to lots of transmitters that happen to
transmit that same data on the same frequency.

I wonder whether the SFN will lead to null areas of the country where two
(or more) transmitters happen to combine destructively so as to produce a
minimum signal level. Bad luck for anyone who lives in one of those areas.
:-(

  #20  
Old January 26th 18, 07:56 AM posted to uk.tech.digital-tv
Mark Carver[_2_]
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Posts: 439
Default Problems today with muxes 7 and 8

On 26/01/2018 08:53, NY wrote:
"Mark Carver" wrote in message



I wonder whether the SFN will lead to null areas of the country where
two (or more) transmitters happen to combine destructively so as to
produce a minimum signal level. Bad luck for anyone who lives in one of
those areas. :-(


Well indeed. The change of GI yesterday, is to reduce the occurrence of
those areas, but it will be interesting to see what happens as more
and more transmitters move to 55/56. We won't know for a while yet,
Mendip and Waltham are well separated !


--
Mark
Please replace invalid and invalid with gmx and net to reply.
 




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