[mythtv-users] no channel lock - live TV

[nick]

On Thursday 01 May 2008 17:32:46 Krzysztof Adamski wrote:
> I have the same problem with Myth locking onto some channels, yet when I
> run the Windows program HDHomeRun Config GUI it has no problem tuning
> and showing the same channels using VLC.
> It seems that Myth isn't as good at extracting the signal from the HDHR
> as it could be.
>
> K
>
> On Thu, 2008-01-05 at 10:02 -0400, Jay Summet wrote:
> > I'm going to assume you are using a HTDV tuner, with an Over the Air
> > (OTA) antenna.  (Because that's what I have...)
> >
> > I ran into this problem with weak signals. MythTv has a setting (I think
> > it's in the backend, and you have to use mythtv-setup to access it) for
> > how many MS/seconds to wait before giving you the error message. By
> > default it is around 2 or 3 seconds. I upped mine to 5 seconds and for
> > those hard-to-tune channels it would allow my Silicon Dust HDTV tuner to
> > lock onto the channels before Myth gave the error message. So try making
> > that timeout longer and see if it helps.
> >
> > Bigger picture, if a weak signal is indeed your problem, you need to
> > improve the signal. (I live close to transmitters, but had the problem
> > when trying to use an indoor antenna. As soon as I mounted the antenna
> > outdoors, the Silicon Dust box locked onto signals much faster.)
> >
> > Side Note: You can get a signal that is TOO STRONG! If you live near a
> > transmitter and have a good outdoor antenna, you can get a signal with
> > 100% signal strength, but that suffers from noise (due partially to
> > multi-path reflections, and partially to the fact that the signal is
> > overpowering the tuner).  This will exhibit itself as a channel that
> > tunes in quickly, but sometimes has "glitches" when the SNR drops to
> > 20-30% range (while the signal strength remains at 100%).  So, if
> > anybody has great reception (100% signal strength on all channels) but
> > is suffering from glitches on one or two of the channels, you may
> > actually want to weaken your signal!  I did this with a 16db attenuator.
> > (I bought various attenuators: 3, 6, 10, and 16db and it turns out that
> > the 16db attenuator worked the best! I wasn't expecting to have to
> > attenuate the signal that much!) I can still receive all of the channels
> > I had before, and the glitches have disappeared from the one that was
> > causing me problems.
> >
> > Jay
> >
> > Nick Petrik wrote:
> > > Hi All,
> > >
> > > I have seen many posts about this issue but no answers that would help
> > > me to get this issue solved.
> > >
> > > I have successfully scanned the channels using MYTHTV. I also know that
> > > the card works because it works with other progs such as kaffeine.
> > >
> > > But everytime I want to watch live TV in Mythtv I get the message
> > > telling me that I should have got a channel lock by now. Nothing more.
> > > Is there anything I might have missed? Thanks for your help / Nick
> >
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>
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Thanks a lot for all the info. However I have set the wait time to 5 sec and 
it still does not work.  As other linux apps work perfectly with the card I 
doubt that there is anything wrong with the signal.
Maybe I should say that I use a Terratec PCI DVB C card on a 64 Ubuntu 8.04 
system using the MANTIS DVB driver.

Is there anything else I should try out? Thanks Nick