[mythtv-users] UK DVB-T Mendip Tuning Fails with Error: Wrong PMT

[Nigel Jewell]

Hi all,

Up until about 2 months ago I was able to receive all Freeview channels 
on my MythTV box without any issues using a Hauppage Nova-T DVB card 
from the Mendip transmitter, however at the end of May I noticed that 
all channels on a single multiplex were failing to tune.

If I plug the aerial directly into my TV (which also has a Freeview 
tuner) I receive all channels with good quality, so I can safely assume 
that I should be able to pick it up.

Using dvbscan as:

/usr/bin/scandvb -u -vvv uk-Mendip

I can see the channels with the same multiplex information that they had 
before (for example):

ITV4:842000000:INVERSION_AUTO:BANDWIDTH_8_MHZ:FEC_3_4:FEC_3_4:QAM_16:TRANSMISSION_MODE_2K:GUARD_INTERVAL_1_32:HIERARCHY_NONE:601:602:28032:24

But when I try to tune I see from the backend PMT errors (for example):

...
mythbackend.log:2011-07-05 21:19:37.876 
DTVSM(/dev/dvb/adapter2/frontend0) Error: Wrong PMT; pmt->pn(26624) 
desired(28032)
mythbackend.log:2011-07-05 21:19:37.909 
DTVSM(/dev/dvb/adapter2/frontend0) Error: Wrong PMT; pmt->pn(26240) 
desired(28032)
...

Something of interest is that dvbscan fails to spot the multiplex 
descriptor (no sign of 842000000) - despite the fact that it spots the 
channel:

parse_terrestrial_delivery_system_descriptor:496: 0x3098/0x1041 
794000000:INVERSION_AUTO:BANDWIDTH_8_MHZ:FEC_2_3:FEC_1_2:QAM_64:TRANSMISSION_MODE_8K:GUARD_INTERVAL_1_32:HIERARCHY_NONE
parse_terrestrial_delivery_system_descriptor:496: 0x3098/0x200c 
738000000:INVERSION_AUTO:BANDWIDTH_8_MHZ:FEC_2_3:FEC_1_2:QAM_64:TRANSMISSION_MODE_8K:GUARD_INTERVAL_1_32:HIERARCHY_NONE
parse_terrestrial_delivery_system_descriptor:496: 0x3098/0x3002 
802166670:INVERSION_AUTO:BANDWIDTH_8_MHZ:FEC_2_3:FEC_1_2:QAM_64:TRANSMISSION_MODE_2K:GUARD_INTERVAL_1_32:HIERARCHY_NONE
parse_terrestrial_delivery_system_descriptor:496: 0x3098/0x3006 
802167000:INVERSION_AUTO:BANDWIDTH_8_MHZ:FEC_2_3:FEC_1_2:QAM_64:TRANSMISSION_MODE_8K:GUARD_INTERVAL_1_32:HIERARCHY_NONE
parse_terrestrial_delivery_system_descriptor:496: 0x3098/0x5000 
754166670:INVERSION_AUTO:BANDWIDTH_8_MHZ:FEC_3_4:FEC_3_4:QAM_16:TRANSMISSION_MODE_2K:GUARD_INTERVAL_1_32:HIERARCHY_NONE
parse_terrestrial_delivery_system_descriptor:496: 0x3098/0x5040 
754167000:INVERSION_AUTO:BANDWIDTH_8_MHZ:FEC_2_3:FEC_1_2:QAM_64:TRANSMISSION_MODE_8K:GUARD_INTERVAL_1_32:HIERARCHY_NONE
parse_terrestrial_delivery_system_descriptor:496: 0x3098/0x6040 
778167000:INVERSION_AUTO:BANDWIDTH_8_MHZ:FEC_2_3:FEC_1_2:QAM_64:TRANSMISSION_MODE_8K:GUARD_INTERVAL_1_32:HIERARCHY_NONE

Any ideas?  I'm not sure where to begin with this as it could be a fault 
of the signal, of the kernel drivers, or of MythTV ... or maybe my 
channel configuration data ...

I've pasted the channel configuration from the database below.

Kind Regards,
Nige.

mysql> select * from channel inner join dtv_multiplex on channel.mplexid 
= dtv_multiplex.mplexid where callsign = 'ITV4'\G
*************************** 1. row ***************************
            chanid: 160024
           channum: 24
            freqid: NULL
          sourceid: 1
          callsign: ITV4
              name: ITV4
              icon: /mythtv/icon/ITV4.png
          finetune: NULL
      videofilters:
           xmltvid: itv4.itv.co.uk
       recpriority: 0
          contrast: 32768
        brightness: 32768
            colour: 32768
               hue: 32768
          tvformat: Default
           visible: 1
     outputfilters:
     useonairguide: 0
           mplexid: 16
         serviceid: 28032
          tmoffset: 0
   atsc_major_chan: 0
   atsc_minor_chan: 0
       last_record: 2011-06-11 20:55:02
default_authority:
        commmethod: -1
           mplexid: 16
          sourceid: 1
       transportid: 24576
         networkid: 9018
         frequency: 842000000
         inversion: a
        symbolrate: 0
               fec: auto
          polarity: v
        modulation: qam_64
         bandwidth: 8
      lp_code_rate: 3/4
transmission_mode: 2
    guard_interval: 1/32
           visible: 0
     constellation: qam_16
         hierarchy: n
      hp_code_rate: 3/4
           mod_sys: UNDEFINED
           rolloff: 0.35
        sistandard: dvb
    serviceversion: 8
   updatetimestamp: 2010-05-31 19:29:14
default_authority: