Ok, so it's been a week and I'm still on DLM-2 (also tried a manual resync).  Time to take action!

I've increased my SNRM target by 1db via the Fritz 'Line Settings' tab:



My stats now look like this:

 

So I've dropped ~1mbit from my receive line speed, but my errors seem to have dropped quite a bit (FEC is about half of what it was before and CRC errors seem to be less although I've only had it running in this config for a couple of hours so it's early days yet).


I also had an idea last night which I think may help us to work out what Mean Time Between Errors (MTBE) rate is required to transition to a better DLM profile.  If we record what our CRC per minute (CRCPM) a day or two during a particular sync period and then make a note of what DLM profile we get changed to (or left on) and we can get enough people involved, we may be able to spot a trend.

What do you guys think about that idea?