we are also getting a bad noise margin on our upstream rate (6.6dB)
That's not bad! Who told you that? That's perfectly normal! It means it was 6dB at sync-time and had since wandered slightly up. In fact, it shows that noise itself has decreased a bit since sync-time, which could well have been at nighttime.
Edited for justification.
1999: Freeserve 48K Dial-Up => 2005: Wanadoo 1 Meg BB => 2007: Orange 2 Meg BB => 2008: Orange 8 Meg LLU => 2010: Orange 16 Meg LLU => 2011: Orange 20 Meg WBC
Edited by XRaySpeX (Tue 05-Aug-14 22:35:52)