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[ktz392837]

When I look at my QLN in DSLstats all tones seem to have a +- 2 or 3dBm/Hz variation gradually going lower in the graph the higher the tone numbers.  I believe this is generally fine.

However, there are a couple of distinct areas around the 200-300 and 3100-3200 tones where the clump of values have a general base line value but can peak many times over the range of tone numbers (e.g. 10-15dBm/Hz variation) and then back to normal outside these tone ranges?

Is this something that can normally happen to a line (e.g. crosstalk) as it has already had albeit a relative small hit on download sync speeds? 

ECI cabinet, Fast Path.  Low ES/h (currently 3/h) with generally no SES (I do got a odd few every now again 0/1/2 per day) and few CRC errors (20/h).  Every so often though the line can go "mad" with many tens of thousands CRC errors and corresponding hour or two of 75 ES / 10 SES.   Attenuation is solid for weeks but it then may change +-0.5db and stay at that for days and then go back to the last value for weeks.  DLM has never intervened to my knowledge I just usually disconnect for an hour or two and the line seems to come back fine.

Thanks

[re0]

A capture of the QLN from DSLsats wouldn't kill you! And it would certainly give us a better view of the total spectrum.

Though, from how you're describing it, it seems to be OK.

However, there are a couple of distinct areas around the 200-300 and 3100-3200 tones where the clump of values have a general base line value but can peak many times over the range of tone numbers (e.g. 10-15dBm/Hz variation) and then back to normal outside these tone ranges?

I believe this is normal for those lower tones. You have to remember that ADSL also will also almost certainly exist alongside VDSL (FTTC) deployments, and ADSL2+ has 512 sub-channels (up to a frequency of 2.2 MHz). The peaks could be where Power Spectral Density (PSD) comes into play as it is less than that of ADSL (so ADSL can actually impact VDSL as opposed to the other way around). For myself, I see peaks from between 200 until around 500 where the line evens out.

I could be COMPLETELY wrong, but I await someone of experience to confirm this.

Edit:
I should add that the above doesn't confirm or explain why tones 3100-3200 (~13.37-13.80 Mhz) are impacted. Not sure which equipment would operate on here.

[ejs]

Sharp peaks in the lower tone range mentioned (200-300) could be due to AM radio stations broadcasting on those frequencies. There might be some noise from ADSL on other lines, but I think that would be fairly evenly spread over the portion of the spectrum used by ADSL lines on your cabinet.

I think Power Spectral Density won't have anything to do with it, QLN, Quiet Line Noise, is the noise detected without any of your own signal on the line.

[ktz392837]

Thanks for replies.  I did try a graph post but failed miserably (my old age) so went old school trying to explain.

[konrado5]

I think Power Spectral Density won't have anything to do with it, QLN, Quiet Line Noise, is the noise detected without any of your own signal on the line.

I think QLN is Power Spectral Density of noise.