I've read at ADSL specifications that line attenuation is average across all available frequiences (not only all used).
I thought we'd been here before - Ive quoted this numerous times
~ What is the difference between Line Attenuation and Signal Attenuation?Routers that display two sets of attenuation figures are usually reporting the Signal Attenuation and Line Attenuation. In these cases it can be taken to mean:-
Line (or Loop) Attenuation is an average of all the tones available for use in the relevant dsl spectrum - regardless of if the tones are in use or not.
Loop attenuation is calculated during the transceiver training phase of the sync process and is an estimation of the line attenuation averaged through all the upstream or downstream subcarriers.
Signal Attenuation is monitored and reported as an ongoing process and can sometimes be affected by ongoing changes in line conditions. Calculation is performed as the difference between the power transmitted at the far end and the power received at the near end.
Signal attenuation is based an average of the frequency bins actually in use.
You then went and asked over at TBB where iirc PhilT (yarwell) independently told you practically the same thing.
Im not getting dragged into this...
but I thought everything had gone back to normal & how it was before once they'd finished. I think youre getting too hooked up on attenuation again. With
ADSL the specifications for the routers measuring of attenuation arent laid out in stone and different modems use different figures anyhow. Its only with VDSL that attempts are being made to standardise it.
Funny enough I quoted the following paragraph to someone else today when talking about KL0 on a router Im currently testing. KL0 is kind of related to attentuation.. and we are talking VDSL here which has more guidelines than ADSL
The exact way in which this parameter is determined is not currently specified by the standards but rather it can be determined in any manner deemed appropriate by DSL modem manufacturers. Indeed the standard seems to anticipate that both the network-side DSL modem and the customer side DSL modem may make an estimation of kl0 (since there is provision for both of these devices to send a message containing such an estimation from one device to the other) but no guidance is given as to which of these estimations should be used by the customer side DSL modem in order to generate its UPBO mask, or whether, for example, they should be combined in some way. The standard does include a note (see G 993.2 section 7.2.1.3.2) suggesting one possible approach for estimating kl0 (this method involves identifying the insertion loss at an unspecified number of different frequencies (provided they are within the range of frequencies between 1 MHz and the maximum usable VDSL2 frequency applicable to the modem—and selecting the minimum value of the ratio of the insertion loss to the square root of the frequency at however many different frequencies are selected for evaluation of this ratio, which could be just one). In general, however, many modems calculate this value based on only one or very few measurements at different frequencies of the amount of the insertion loss (i.e. the attenuation experienced by signals received over the line).
Its even possible that whilst the work was being done noise from pneumatic drills eg caused your line to drop and the atten was measured at this time
Im really not going to go there... because at the end of the day everythings back to normal now and its not going to tell you anything useful about your line that is going to be used for fault tracking.
I dont have anything further to add.
Ive told you before, people will answer if they feel they have something useful to add, but please dont call people out and put them under pressure to answer something when they know that within a short time theres going to be a zillion more questions for which there are no answers.
