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user_8b2e56
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Sun, Apr 18, 2021 3:59 PM

sb8200 technical issues

Xfinity 400Mbps "blast" service but I'm only getting 30Mbps down (am getting 10Mbps up as advertised); I've seen several other posts but no firm resolution; modem sporadically shows the "blue" Docsis 3.1 light for download but mostly shows green. Will post status and error logs below.

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user_8b2e56

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7 Messages

1 m ago

here is the modem event log

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user_8b2e56

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1 m ago

here is status summary - channel stats next

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user_8b2e56

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1 m ago

channel stats - page 2 - I believe these all look good (as does the other page)

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andyross

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Your OFDM SNR is too low, which is why that won't reliably connect. You may have some noise issues with the higher frequencies, or possibly a trap or other problem causing a sharp signal dropoff at the highest frequencies.That 702MHz is where the OFDM starts, but it probably runs up to 850MHz or so as it's treated as one extra wide channel.

Signal levels are OK, although the upstream is lower than normal.

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1 m ago

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user_8b2e56

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thanks for the insights - what can I do about that OFDM SNR issue?

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EG

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1 m ago

@user_8b2e56 

FWIW. There is a known glitch with some makes / models of modem's firmware where the measuring mechanism incorrectly reads the power level, the SNR, and the bit errors for that channel. So it reads many errors when there really aren't. 

 

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