Hi,
Our line (20CN ADSL 1 Max) shows regular but small scale variations in downstream SNR, showing as variations in the Noise Margin as reported by the router. Variation during the day is round 0.3dB, with what appears to be a regular pattern. Towards evening the noise margin reduces and the variations become larger and more random.
See attached graphs from Routerstats Lite, one showing typical daytime pattern, one the night and one showing the transition.
Questions - given that the router is staying synched throughout, what's the likelihood that these variations are actually causing any issues? And secondly, does that repeated pattern match any sort of known interference source? It seems to be around a 4 minute cycle.
Router is a Linksys WAG320N by the way.
Thanks, Tony S