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View Full Version : OOB SNR. How low is too low?


morac
04-18-2008, 12:23 AM
Recently I've noticed the the SNR on the OOB frequency for one of my cards is getting pretty low (around 17 dB at the lowest). My cable box uses the same frequency for it's OOB communication and it is ever lower than my TiVo (15 dB which it reports as poor).

Everything seems to be working and my picture is fine as is my Internet and CDV so it just seems to be that frequency.

Does anyone know how low of a SNR the OOB channel can be and still work reliably?

litkaj
04-18-2008, 04:50 PM
With all the attenuators sitting on the back of my S3 (FiOS TV) my OOB drops to 15-16 but it always has an OOB signal lock.

cableguy763
04-18-2008, 05:00 PM
The OOB is your forward data carrier and is more than likely using QPSK modulation. QPSK is much more robust than QAM and can be much closer to the noise floor. If your box is working, you shouldn't worry. If it was affecting the box or tivo, the cable box would probably take a really long time to boot (if at all), the cards could lose their channels maps and emm's, and the box could lose guide data.

ilh
04-18-2008, 05:12 PM
BTW, I think OOB lock time might be a decent approximation to time since last reboot.

morac
04-18-2008, 05:32 PM
BTW, I think OOB lock time might be a decent approximation to time since last reboot.

Or the last time your cable went out. ;)