[mythtv] MtrhTv: Uk Mendip Transmitter issues

[Terry Barnaby]

On 04/07/10 10:39, John Pilkington wrote:
> On 04/07/10 09:34, Terry Barnaby wrote:
>> Hi,
>>
>> I have been having quite a problem to get MythTv to work well after
>> the Multiplex changes on the Mendip transmitter in April.
>> Apart from issues where neighbouring transmitter multiplexes
>> that are are found (from info from the Mendip transmitters
>> info lists) and added to the list, which I have got around,
>> the main issue is that I don't seem to be able to tune to
>> channels from the "A" Multiplex.
>>
>> I have been playing around with dvbscan to check things out and
>> to make sure by signal levels etc are about right. However
>> I see a strange issue. If I give dvbscan the main "PSB1"
>> multiplex to start with if finds the other multiplexes but
>> gets some of the parameters wrong.
>>
>> The correct settings I believe are:
>> T 794000000 8MHz 2/3 NONE QAM64 8k 1/32 NONE # PSB1
>> T 738000000 8MHz 2/3 NONE QAM64 8k 1/32 NONE # PSB2
>> T 802167000 8MHz 2/3 NONE QAM64 2k 1/32 NONE # A
>> T 754167000 8MHz 3/4 NONE QAM16 2k 1/32 NONE # C
>> T 778167000 8MHz 3/4 NONE QAM16 2k 1/32 NONE # D
>>
>> These work when you manualy set them for dvbscan.
>>
>> However if dvbscan scans from the main multiplex it returns:
>> initial transponder 794000000 0 2 9 3 1 0 0
>> >>> tune to:
>> 794000000:INVERSION_AUTO:BANDWIDTH_8_MHZ:FEC_2_3:FEC_AUTO:QAM_64:TRANSMISSION_MODE_8K:GUARD_INTERVAL_1_32:HIERARCHY_NONE
>>
>>
>> >>> tune to:
>> 738000000:INVERSION_AUTO:BANDWIDTH_8_MHZ:FEC_2_3:FEC_1_2:QAM_64:TRANSMISSION_MODE_8K:GUARD_INTERVAL_1_32:HIERARCHY_NONE
>>
>>
>> >>> tune to:
>> 802167000:INVERSION_AUTO:BANDWIDTH_8_MHZ:FEC_2_3:FEC_1_2:QAM_64:TRANSMISSION_MODE_8K:GUARD_INTERVAL_1_32:HIERARCHY_NONE
>>
>>
>> WARNING: >>> tuning failed!!!
>> >>> tune to:
>> 754167000:INVERSION_AUTO:BANDWIDTH_8_MHZ:FEC_2_3:FEC_1_2:QAM_64:TRANSMISSION_MODE_8K:GUARD_INTERVAL_1_32:HIERARCHY_NONE
>>
>>
>> WARNING: >>> tuning failed!!!
>> >>> tune to:
>> 778167000:INVERSION_AUTO:BANDWIDTH_8_MHZ:FEC_2_3:FEC_1_2:QAM_64:TRANSMISSION_MODE_8K:GUARD_INTERVAL_1_32:HIERARCHY_NONE
>>
>>
>> WARNING: >>> tuning failed!!!
>>
>> It has got the settings wrong in the last three multiplexes.
>>
>> Is this a bug in dvbscan or is the transmitter sending out the wrong
>> info ??
>>
>> If I create channels.conf by manually adding the channels from each
>> multiplex
>> in turn (setting the parameters correctly) I can tune into the channels
>> with tzap ok. If I use tzap to tune in "Virgin1" which is in multiplex A
>> I get a lock, a reasonable signal level, a reasonable SignalToNoise
>> ratio, and a low bit error rate between 0 and 8.
>>
>> If I use these Multiplex values and enter them into Mythtv as its
>> transponders and re-scan for channels, all works fine and I get all of
>> the channels listed.
>> However if I try and tune to "Virgin1" I get no-lock.
>>
>> My feeling is that MythTv is also getting the DVB parameters wrong.
>> Is there a way I can get MythTv (frontend or backend) to list the DVB
>> parameters it is using ?
>>
>> Cheers
>>
>>
>> Terry
>>
> Hi: This is really a question for the mythtv-users list.
>
> I'm not in the Mendip area and I don't know how reliable this site is,
> but it looks useful.
>
>> http://www.ukfree.tv/txdetail.php?a=ST564488
>
> It says that all 5 SD muxes are now 64QAM:
>
>> Before switchover, the public service broadcasting multiplexes were 1,
>> 2 and B; afterwards they were first PSB1, 2 and 3 but now called BBCA,
>> D3+4 and BBCB. The commercial multiplexes A, C and D had initial
>> post-switchover names COM4, 5 and 6; now they are SDN, ArqA and ArqB.
>> At switchover BBCA, ArqA and ArqB will switch from 16QAM to 64QAM mode
>> transmission, so five multiplexes will transmit in the 64QAM (2/3) 8k
>> mode. BBCB is used for Freeview HD (DVB-T2, 256QAM), and has a
>> pre-switchover service on selected main transmitters.
>
> What release of MythTV are you using? Details for each channel are shown
> in the Channel editor section of mythtvsetup.
>
> HTH
>
> John P
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Ok, I will repeat the email on the user list and there carry on there.

Yes, that web site I have used, Multiplexes C and D
are stated as being QCAM-16 at the top though and they work as QCAM-16 (at least
the scandvb works when set as this).

I am using MythTv 0.23 -3 from RPM's on Fedora12.

I will move this question to the users group.

Cheers


Terry