AnonMan, that situation is indeed crummy. Due to the highly intermittent nature tracking it down (to a specific cable/area of the node) sounds very difficult and time consuming. On the other hand, if it's happening on the entire node, that means more than just you is impacted -- bringing this up with your LFA may be the next step for you. Node-level issues I think are given more attention than individual customer issues.
Also, I've been told by both the Network Engineering Supervisor as well as the network/maint tech who was out here, that Comcast does
have a "history view" for SNR levels on a per-channel basis (including support for bonding), so they should be able to see it there. Meaning, they have something similar to what I provide here (from my own modem) but probably with less granularity (I poll every 2 minutes): »jdc.koitsu.org/snrgraph/
-- I know Comcast having that information doesn't help narrow down where on the cable network/segment the problem lies, but it would act as evidence (for your LFA) that Comcast acknowledges there's a problem affecting multiple people on your node.--
Making life hard for others since 1977.
I speak for myself and not my employer/affiliates of my employer.