Twisted Pair RJ11 Broadband Modem Performance

Ian

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As you may have seen in other threads, I've been trying to tackle dwindling performance from my fibre broadband connection. I live about 800m (as the crow flies) from the BTO Cabinet and my cable length may be something like 1.8km - so I'm right on the edge of fibre being worthwhile.

At first, I was getting 21Mbps and that has now dwindled to 18Mbps download.

I've made lots of changes to our internal wiring, added a better filter and pair our existing Router/Modem with the ISP supplied modem which seems to connect with a slightly better SNR.

The last change I've made surprised me. I switch from the supplied flat RJ11 modem cable to a twisted pair RJ11 cable (This one from Amazon). My line attenuation stats went from 27.8dB to 27.0dB and the noise margin improved from 11.8dB to 12.6dB - these aren't huge improvements, but improvements nevertheless. The SNR is already higher than the 6dB it was when I already started making tweaks, but DLM hasn't kicked in to move me to another profile yet. My upload speed did increase from @5000Mbps to 5391Mbps immediately though.

If you're looking to tweak your connection, it may be worth considering - the cables aren't much and if you're handy with crimping tools it will cost next to nothing (you can re-use network cable).
 

muckshifter

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Have you looked into a 'filtered faceplate' to replace any/all filters ... you can get a 'proper' BT one or a cheaper somethingorother, both can be had from Amazingdotcon. :)
 

Ian

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Have you looked into a 'filtered faceplate' to replace any/all filters ... you can get a 'proper' BT one or a cheaper somethingorother, both can be had from Amazingdotcon. :)

Yep, got the MkIII at the moment :). Lots of little improvements here and there, and they're starting to add up :D.
 

Ian

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Just took a look at the VDSL stats and it looks like I could get closer to 26Mbps once DLM starts loosening off :D:

DS Actual Rate : 17998000 bps
DS Attainable Rate : 26692304 bps
 
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Try winding your cables around some Ferrite rings or Core Filters clip on. They only cheap really. Sorta thing you see on cables for power supplies etc

Might make a difference.
I usually strip them out of old PSUs and TVs save buying them
 

Ian

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I was wondering about Ferrite filters, but wasn't sure if EMI would be a problem on a short 1m shielded cable - I suppose there's no harm in trying one! I've got some clip-on ones I can switch over :).

I've got a power conditioner arriving tomorrow, as it looks like the homeplugs in our house may also operate at the same freq as VDSL - so worth a shot.

I'll update this thread as I make progress - although it may take ages for DLM to pick up the changes.
 

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