[mythtv-users] Having trouble recording OTA since adding a second tuner

John P Poet jppoet at gmail.com
Mon Mar 15 19:11:22 UTC 2010


On Mon, Mar 15, 2010 at 1:07 PM, Terence Ripperda <ripperda at gmail.com> wrote:
> On Mon, Mar 15, 2010 at 12:06 AM, Kevin Ross <kevin at familyross.net> wrote:
>>
>> Terence Ripperda wrote:
>>>
>>> I've been experimenting with MythTV, and recently added a second tuner.
>>> Ever since adding the second tuner, I've been having random trouble locking
>>> to the OTA signal on one of the 2 tuners. I haven't gathered a lot of data
>>> yet, but it appears to be random, isn't tied to either tuner specifically.
>>> Usually, when this happens, the current tuner will tune to some stations,
>>> but not other stations. if I switch to the "other source", I'm then able to
>>> tune into the station I'm having trouble with.
>>>
>>> Both tuners are identical Hauppauge HVR950Q usb sticks, using the xc5000
>>> driver.
>>>
>>> I did have to use a coaxial splitter to split the incoming signal to both
>>> of the usb sticks. I noticed other mails on this list that indicated signal
>>> loss can cause problems like mine.
>>>
>>> I'm curious what the steps towards debugging something like this would
>>> be. if this is a signal loss issue, I can purchase a booster, but I'd like
>>> to know if there's a way to verify this is the cause, before I do spend
>>> money.
>>>
>>> I did catch this in my logs:
>>>
>>> 2010-03-04 19:00:02.629 Started recording: Community "Physical
>>> Education": channel 1361 on cardid 2, sourceid 1
>>> 2010-03-04 19:00:42.186 UPnpMedia: BuildMediaMap VIDEO scan starting in
>>> :/hosts/readynas/Mythtv/
>>> videos:
>>> 2010-03-04 19:00:42.512 UPnpMedia: BuildMediaMap Done. Found 115 objects
>>> 2010-03-04 19:01:15.262 AutoExpire: CalcParams(): Max required Free
>>> Space: 3.0 GB w/freq: 15 min
>>> 2010-03-04 19:01:43.750 DevRdB(/dev/dvb/adapter0/frontend0) Error: Poll
>>> giving up
>>> 2010-03-04 19:01:43.757 DVBSH(/dev/dvb/adapter0/frontend0) Error: Device
>>> error detected
>>> 2010-03-04 19:01:43.814 DVBRec(2:/dev/dvb/adapter0/frontend0) Error:
>>> Stream handler died unexpectedly.
>>> 2010-03-04 19:01:44.335 TVRec(2): Changing from Watching RecordingOnly to
>>> None
>>>
>>> I did not see any other errors in the kernel output (from the xc5000
>>> driver).
>>>
>>> Thanks for any help/tips,
>>> Terence
>>
>> To determine if the splitter is lowering your signal strength too much,
>> when you have problems tuning a channel, remove the splitter and plug the
>> antenna cable directly into the tuner and see if you can then tune the
>> channel.
>
> Thanks Kevin, I'll give that a try tonight. is there also a way to log/see
> what the signal strength is of an active broadcast? I'd like to compare
> strength between various test cases.

I would also suggest trying a different USB port.  If both USB ports
are connected to the same "hub" (even if that hub is on your
motherboard), there may be some contention there.  Also make sure both
USB ports are 2.0 and not 1.1 ports.

John
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