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R5A10 Refuses to record ONE channel
http://forum.linhes.org/viewtopic.php?f=6&t=3714		 Page 1 of 1
Author:  Liv2Cod [ Sat Feb 26, 2005 8:07 pm ]
Post subject:  R5A10 Refuses to record ONE channel
I have the oddest problem. After upgrading my box from R4 to R5A10 (0.17 Myth) I can record all channels perfectly but one. Channel 11.1, the NBC affiliate in my area, will fail to record every time with the dreaded "no signal level" error. This is with either my HD-2000 or HD-3000 tuner cards. I can tune in the signal using "dtvsignal" and it comes in perfectly. It's just that Myth can't tune it.

I'm really out of ideas as to how to even debug this problem. I look at the channel table and it seems perfectly fine. The frequency is 12-1 as it should be. The other entries all look similar, and they work fine. Only NBC fails to record. Before I loaded 0.17 it recorded fine.

I left a message on myth-users but no responses yet.

I'm stumped.
Author:  Greg Frost [ Sat Feb 26, 2005 11:19 pm ]
Post subject: 
Those are dvb cards right? To receive a channel you need to have specify the correct ids for the video and audio for it to demux them from the digital stream (each tuned frequency is capable of carrying multiple channels). Tuning the card only involves receiving the full stream, so it is possible for it to report that it is tuning correctly (i.e good snr/unc) but not receive any actual video/audio. Some stations change the ids that they are using to broadcast video and audio in different timeslots (a real pain). If you tuned the channels at one time and then tried to record at another, the channels may not be on the stream anymore.

Can you receive the video using tzap -r "channel name" (with an appropriate channels.conf) and mplayer /dev/dvb/adapter0/dvr0 in another window?
Author:  Xsecrets [ Sun Feb 27, 2005 12:49 am ]
Post subject: 
nah the hd3000's use a modified bttv driver at this point, although I hear they are thinking of going dvb, and someone has actually written a dvb driver for the 3000, but it is not the one that comes with knoppmyth.
Author:  Greg Frost [ Sun Feb 27, 2005 4:36 pm ]
Post subject: 
Do they pick up terrestrial digital tv signals though? I assumed they did because iof the HD part of the card name, but operhaps that is just a marketing ploy). Because if they do the essence of what I said should still apply (just not sure how it is handled with the modified bttv driver).
Author:  Xsecrets [ Sun Feb 27, 2005 4:39 pm ]
Post subject: 
yes they do pick up OTA ATSC signals.
Author:  Liv2Cod [ Sun Feb 27, 2005 4:43 pm ]
Post subject: 
Well, I found the problem... :oops:

Further testing with dtvsignal showed that the signal on channel 12 was "spotty" -- it would suddenly drop to zero and come right back on. Antenna position did not matter. I have an amplifier on the antenna, which I replaced with a different model. It helped the signal on channel 12 immensely (although some of the upper channels were actually reduced a bit).

It only goes to show you the wisdom of a saying we have at work... Whenever you think you've solved a problem, look deeper and you'll find another!
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