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Standard User ratonastick
(newbie) Thu 09-Dec-10 12:37:06
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Analysing graph in DMT tool


[link to this post]
 
Hi, My connection speed has been quite low for the reported attenuation for some time.
I swapped out my Netgear router and connected a Speedtouch 546v6 so i could run DMT tool v7.
Could someone who is familiar with this utility please give me an idea where the problem may be ?

Router is connected to master socket via Pressac Filtered faceplate, no extensions.
I've tried the test socket in the master with different plug-in filters,cables and routers with similar speed/attenuation quoted.
Quiet line test with corded phones in test socket, no audible noise/interference.
ISP is Sky Unlimited LLU, G.DMT mode ( ADSL2+ mode was unstable at night so Sky changed it )
>DMT output<

thanks
Alex
Standard User Magsy
(committed) Thu 09-Dec-10 14:02:42
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Re: Analysing graph in DMT tool


[re: ratonastick] [link to this post]
 
The bits per tone part in blue at the top shows how much data you have in each tone, the higher the bar the higher the sync speed.
You have a right mess at the start of the graph and the x axis is showing the frequency range, so you can see that you are picking up interference somewhere.

Here is my graph from a DG834GT on UKOnline, this is not a great connection either but it is and has been for years pretty stable at 4-5mb.

DMT

Edited by Magsy (Thu 09-Dec-10 14:03:22)

Standard User ratonastick
(newbie) Thu 09-Dec-10 14:58:09
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Re: Analysing graph in DMT tool


[re: Magsy] [link to this post]
 
So you think it's interference rather than a dodgy connection on the line somewhere ?
I did get a REIN interference problem sorted just over a year ago, but that could be detected with an AM radio tuned to 612khz.
Sadly I can't detect anything this time using the same method.

thanks
Alex


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Standard User Magsy
(committed) Thu 09-Dec-10 15:27:55
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Re: Analysing graph in DMT tool


[re: ratonastick] [link to this post]
 
Could be either! I'm no expert and I'm out of my depth but my understanding is that the lower tones, the lower frequency signals should travel a long(er) way. So the lower half of the graph in blue should be tall and strong, the longer your line the quicker it will taper off at the end. So a 24mb graph will be a giat blue rectangle all the way out past where ours tails off.

So the fact you have holes in the graph early on in the those tones which should be strong must have something to do with the line.

I had an issue which BT wouldn't resolve, I lost half my sync overnight. The DMT graph for that had a massive dip in the middle of it, like a rollercoaster!

I left it 3 months and could get no fix from BT or ISP. I bought another line and during installation the engineer went to connect the new pair at my local cab. I'd been nice and kissed ass already asking for a good job/pair, he said that he was very very sorry but he'd found my old pair had a join which was floating in six inches of water, he had cut and rejoined it but would have to carry on with the new line (even tho he admited he'd probably fixed the old one)

It turned out that cut n splice he did actually fixed the old line and the graph of that you see above. So now I have a second line I don't need after he has fixed a problem on the first that nobody would admit existed or even look into... :/

You should have at least 4mb sync if not more but my isp kept saying even if you had 512k, we'd class that as ok.

Edited by Magsy (Thu 09-Dec-10 15:28:33)

Standard User ratonastick
(newbie) Thu 30-Dec-10 23:18:20
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Re: Analysing graph in DMT tool


[re: Magsy] [link to this post]
 
Thanks for your assistance Magsy.
I've added a recent plot from DMT v8 using a different Broadcom router.
This time I've used a Dlink DSL-2640B firmware 3.06 .
The output looks very similar to the Speedtouch I used previously, but I would really apprieciate assistance from someone who is very familiar with the DMT tool and/or the technical aspects of ADSL.
No interference on corded phone and upstream frequencies look ok, but slightly higher into the downstream range and it all goes wrong.
Could this be caused by a line fault or corroded joint somewhere ?
Localised REIN interference perhaps ?
Many thanks
Alex
>New plot<
Standard User andyboygsi
(member) Sun 02-Jan-11 17:44:04
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Re: Analysing graph in DMT tool


[re: ratonastick] [link to this post]
 
i think if it was rein its more likely to wipe out the complete bin that it was affecting.

looks like something is affecting the low frequencies, press for a sfi visit and show him your graph. thats the only way you will ind out for sure.

these comments are my own and in no way represent any company that i may or may not be linked too.
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