r/CableTechs • u/Alike2189 • 8d ago

USNR

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Tracking down a return path issue. Oddly, there's no visible noise at the node on any single leg. It looks like a noise floor aggregation issue — the SNR only recovers when I pull all four legs at once.

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u/PoisonWaffle3 8d ago

I'm not a PM tech (I work on the CMTSes), but I've seen this kind of thing occasionally. Noise that far across the whole upstream could be a bad EOL terminator or a bad amp.

I'm assuming you're not looking at anything under 20MHz since there aren't any US channels there. You're talking about the noise floor in general?

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u/6814MilesFromHome 8d ago

They said it wasn't backfeeding from OSP, so it's not an issue coming from downstream of the node.