Lost Tones

Have a Billion DXL modem/router. Been working fine until recently. The dmt tool shows loss of tones from 469 through to 497 basically all the top end frequencies. I'm with Sky on max unlimited (LLU) for internet and BT for phone. The orange ring wire has been removed from the NTE box and all extensions.

This has just started happening since FTTC work began in the exchange. I've noticed that when doing a tracert the Sky gear has changed in the phone exchange. different router hop name.

Would be glad of some thoughts on the matter.

A picture would help a lot when talking bin plots

VDSL2 has its speed and power controlled to try and avoid undue slowdowns for ADSL2+ so it may just be that in your case you are seeing a wee bit more cross talk.

In reply to a post by wingco1:

Would be glad of some thoughts on the matter.

Are you seeing any performance problems because of this?

A picture would help a lot when talking bin plots.

I don't have anywhere to put one unfortunately.

Just a minor drop in download speed.

Tones 469 to 497 are in the band 2.022 to 2.100 MHz which is used for various mobile radios including land and maritime. You are in Cumbria and there are some high power maritime transmitters up there. It could be one of those being picked up or if you are near a harbour the local fleet transmission.

Tinypic is ust one of free image hosting places, useful for this. You don't need an account, juts upload and link.

Uploaded and got this link to share. Not sure it works though.

<a href="http://tinypic.com?ref=2589glv" target="_blank"><img src="http://i61.tinypic.com/2589glv.jpg" border="0" alt="Image and video hosting by TinyPic"></a>

Try:

http://tinypic.com/view.php?pic=2589glv&s=8


They are almost certainly due to external noise being picked up. You are already down at 1 or 2 bits per tone so any small change in noise will kill those off.

The gaps at 300 to 330 or so are MW radio stations.

Edited by MHC (Fri 31-Jan-14 11:02:59)

Thanks for that. Bearing in mind all wires except 2 + 5 are disconnected, would fitting an iPlate filter be beneficial?

Unlikely. The noise being picked up in the wires from the exchange, through the cabinet to your property. There is nothing you can really do about it. Even if you could recover those few tones at the top end, the incremental speed difference would be very small.

Thanks for the information. Just one more question if I may. Will this have any effect on FTTC?

In terms of stopping you hitting your speed estimate no. They take into account general levels of interference

VDSL2 uses all the way up to 17 MHz

Much obliged.