[mythtv-users] multiple transmitters - same channel
Doug Scoular (dscoular)
dscoular at cisco.com
Fri Mar 21 13:00:22 UTC 2014
On 21/03/2014 11:00 pm, "mythtv-users-request at mythtv.org"
<mythtv-users-request at mythtv.org> wrote:
>Subject: Re: [mythtv-users] multiple transmitters - same channel
>Message-ID: <532BFD72.2070401 at thewatsonfamily.id.au>
>Content-Type: text/plain; charset=ISO-8859-1; format=flowed
>On 20/03/2014 12:07 AM, John Pilkington wrote:
>> On 19/03/14 12:45, Mike Perkins wrote:
>>> On 19/03/14 03:08, my thtv wrote:
>>>> I have been using Mythtv for some years, however, recently here in
>>>> Australia they have been retuning the digital (DVB) transmit
>>>> frequencies.So I
>>>> took the opportunity to re-scan my channels.However, I am in range of
>>>> a number a
>>>> transmitters and in some instances they are carrying the same services
>>>> signal strength and quality varies between them.
I¹ve experienced a fair bit of weirdness coming to a head with the recent
Before the Sydney rescan I noticed that SBS HD came and went, no mythtv
rescan, just disappeared and then came back seemingly once every couple of
I didn¹t really mind since the Standard Definition SBS channel was always
present. My guess was that this was something that shepherd (a really
great Australian tv_grab_au implementation) and mythfilldatabase were
somehow conspiring to do.
Since it was approaching rescan time I decided to be brave and that I
would delete all my channels in mythtv setup (on 0.27, mythbuntu 12.04.4
LTS) in the hope that this might cure the above behaviour. I know that I
don¹t get the main Sydney channels and my antenna points North towards
Bouddi/Newcastle (Bouddi being nearer as the crow flies) and I get central
coast news and crappy adverts (no offence Newcastle) rather than Sydney
news and ads.
So I had looked up the dates for the Bouddi retune (Thursday, 30th
October 2014) on the outside chance that I was actually tuning to the
Newcastle (Monday, 8th September 2014). Imagine my surprise when all my
SBS channels refused to tune on the Sydney retune day, last Tuesday (18th
March 2014)! All I got was (TL) rather than (TLMS).
So I brought forward my plans, used mythconverg_backup.pl to make a
backup, deleted all channels and did a full rescan. SBS 1, 2, 3, NITV and
HD all came back with everything else (but with much higher channel
numbers: 849, 850, 851, 852 and 853).
However, the problem is still present; SBS HD disappears and reappears
while the rest appear consistent (not that I watch much live tv other than
Any thoughts on where I should start looking for the culprit ?
I has mysql foo ;^)
mysql> select callsign, channum, transportid, networkid, frequency from
channel, dtv_multiplex where channel.mplexid = dtv_multiplex.mplexid and
callsign like 'SBS%' or callsign like 'NITV%';
| callsign | channum | transportid | networkid | frequency |
| SBS ONE | 849 | 848 | 12802 | 599500000 |
| SBS TWO | 850 | 848 | 12802 | 599500000 |
| SBS 3 | 851 | 848 | 12802 | 599500000 |
| NITV | 852 | 2 | 57 | 536500000 |
| NITV | 852 | 547 | 4112 | 592500000 |
| NITV | 852 | 848 | 12802 | 599500000 |
| NITV | 852 | 2058 | 12812 | 690500000 |
| NITV | 852 | 2480 | 12930 | 704500000 |
| NITV | 852 | 1792 | 4121 | 585500000 |
| SBS HD | 853 | 848 | 12802 | 599500000 |
It¹s weird that the channels went AWOL on the night of the Sydney retune
rather than the planned Bouddi or Newcastle ones. That doesn¹t explain why
SBS HD is occasionally AWOL or, for that matter, why I have so many NITV
entries. I confess I don¹t know much about channum versus transportid
versus network id versus frequency.
Any clues much appreciated.
Oh, and apologies for co-opting this thread. I can change the subject if
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