It is a complex function, involving both real and imaginary numbers. (The equivalent Hlin function actually shows both real and imaginary values per sub-carrier.) In the broadest sense, it is often useful to consider the Hlog plot to show the equivalence of attenuation over frequency.
In the latter simplistic terms, I try to think of the Hlog graph giving an indication of the attenuation, and how it varies across the frequency spectrum. Most importantly is the need for it to be a nice smooth curve - and this one is precisely that. It is when we see dips and oscillations in this graph that we begin to suspect the line has physical problems.
For what little we can see, there is no evidence of a "smoking gun" . . .
Not even the SNRM graph? The fact it currently reads well above 6dB tells us something ... that either DLM has banded the line, or there was a lot of noise at the time of the last sync, that has now disappeared. That suggests the line suffers from something, even if it isn't currently visible.
The QLN graph isn't too bad - it generally represents a low noise line, with the usual kind of "spikes" from radio stations. For example, around tone 115 - my line has a similar spike.
However, there is something of an extra "bulge" between tones 80 and 110 that isn't the normal kind of spike. It might explain a few missing bits around tone 110 ... but I doubt that it is a portent for a large amount of missing speed.
Just as WWWombat has mentioned, above.
Can we get a look at what these other graphs look like at present? Ta.
but drops out for days if there is cold weather. Heavy rain will lower my connection rate too. How do I prove this problem exists because by the time a OR Engineer arrives the weather has changed
Such intermittent faults are the hardest ones to deal with - for both you and the BT engineer. Persistence in reporting issues certainly helps, as does an ISP that responds to issues quickly.
The best way we can help you is if you keep that monitoring software running as much as you can, catching good days as well as bad - something on there is likely to give us a clue when things go wrong. Not all of the BT engineers want to see the evidence afterwards, but sometimes it can act as a flag, so at least *you* know when things are going wrong.
If I sign up for My DSL Web Stats do you think that would help to record faults for OR to view?
I literally can't have another Winter of disconnections cause I work in IT & need my Internet connection.
It can't do any harm, and it helps people on here easily see all the details relevant to your line.
