[vdr] Channel dropout unless femon active

Klaus Schmidinger Klaus.Schmidinger at tvdr.de
Mon Aug 26 10:50:50 CEST 2013

On 25.08.2013 21:31, Richard Scobie wrote:
> Klaus Schmidinger wrote:
>> On 25.08.2013 05:32, Richard Scobie wrote:
>>> Perhaps a little off topic, but I wonder if anyone can shed any light
>>> on the following.
>>> I am viewing a signal that is very close to reception threshold - dish
>>> a little small, STR value 65%, SNR value 67%, but BER and UNC errors
>>> as reported by femon are zero.
>>> As long as I leave the femon plugin active on screen, I can view it
>>> uninterrupted. If I turn it off, within 60 seconds, the picture will
>>> disappear until I activate femon again.
>>> Initally it will only show "SIGNAL" and "CARRIER" indicators active,
>>> then after a short period, everything will lock again and the channel
>>> will re-appear.
>>> I am running the latest vdr version with a TT 6400 S2 full feature
>>> card, with latest drivers and firmware. Relevent drivers would be
>>> perhaps stv090x or stv6110x.
>>> Channel parameters DVB-S2, symbol rate 15000 FEC 3/5  QPSK Video 35Mb
>>> MPEG2 1920 x 1080, Audio MPEG 270Mb
>> Do you have both inputs of the TT-S2 6400 connected to satellite cables?
>> And is there actually a signal on both of them?
> Hi Klaus,
> I have three dishes with dual LNB's, with each LNB output going to two 4x1 diseq switches, feeding each tuner, so both tuners have the same signals available.
> As two whether the other tuner always has a signal present, I cannot say for sure as my channel list has quite a number of itinerant feed channels loaded, which are not always active, so vdr may well be scanning  across empty channels on the second tuner.
> Indeed, this channel I am having trouble with is one of those - a feed from a motor sport event and is only there on certain weekends.
> My somewhat uninformed thought was that perhaps femon's constant polling for front end values was somehow causing a marginal PLL to re-lock, vs the no femon situation where it looses lock on the weak signal and does not reaquire it.

Well, VDR also constantly polls the frontend to see whether it is still locked.

I'm afraid I'm out of ideas then...


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