[mythtv-users] Video breaking up after installing new video card

[Daryl McDonald]

On Fri, May 2, 2014 at 9:15 PM, Phill Edwards <philledwards at gmail.com> wrote:
>> Thanks Daryl, I'm not sure I understood what you said. So I'll describe my
>> set up (hope this little ASCII diagram works OK!):
>>
>> Antenna --
>>          |
>>   | --> TV1 (picture quality good)
>>   |
>>   | --> TV2 (picture quality good)
>>          |
>>   | --> Cheap $5 splitter
>>               |
>>               | --> HD Homerun (2 tuners) --> 1Gb switch --> Mythbackend
>>               |
>>               | --> PCI Card --> Mythbackend
>>
>> Does that make sense? If you still think it's a signal strength issue is
>> there any way I can verify that? And if I need to get a booster, are there
>> different types which are better than others? E.g. do some install at the
>> antenna vs others install at the wall outlet?
>
>
> More info on this... This morning I put 2 programs to record at the same
> time. All different broadcasters so I knew that all 3 tuners would be used -
> 2 on the HD Homerun and 1 PCI card. I watched some of the recordings and
> found two were OK, and one broke up in places. The one that broke up was
> also highlighted yellow in Watch Recordings which I believe indicates a poor
> quality recording.
>
> I assumed that the bad recording would be the PCI card, and the two from the
> Homerun would be OK. After running some queries to track down which tuner
> recorded which program, I found the following:
>
> Homerun tuner 0 = BAD recording
> Homerun tuner 1 = good recording
> PCI tuner 0 = good recording
>
> This surprised me. Surely if one of the Homerun tuners was OK, they would
> both be OK? Unless it's to do with signal strengths varying by channel,
> which I presume could mean:
> - either the poorer channels aren't tuned to the right frequency, or ...
> - they're more susceptible to a overall weakened signal strength?
>
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Ok Phill it seems you have a 3-way splitter feeding a two way
splitter, which indicates to me that your TV is misrepresenting the
situation to you. One 4-way splitter would be better in your case, but
may not be logistically possible so an amplifier may be needed. What
you have done is taken a good signal and reduced it by 3.5db with each
split, splitters vary, it will be printed on the device "-ndb" where n
is a numerical value. Splitting the first time gave you a weakened,
but usable signal to your TV's, splitting again weakened it again,
which I suspect is giving the results you describe. And you can even
have some good and some worse recordings from the same source, but
different channel/multiplex. Other times a bad connector/s can cause
problems, your cable provider could diagnose this for you.
>