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SNR Fluctuation

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SNR Fluctuation

Hi there, can anyone please explain the possible reason for what is happening to my noise margin. I`m using a Netgear DG834Gv3 router and I am now on a 1mb Home service after asking to be changed back from Max which was a disaster fo me- 90k-130k speeds and loads of disconnects.When first changed back to fixed 1mb it was fine for about 3 days then had a week of disconnects ranging from 5hrs to 8hrs. Raised a Question with CS and BT engineer came and checked my line at home- nice guy, fitted me a NTE5 with splitter faceplate. At that time he checked my stats and said they were steady at 59.5db D/S Atten and 8.5db noise margin.After he`d gone(naturally) the Atten went up to 61 and snr started dropping and ended on 1db, so I rebooted the router and it showed 61 Atten D/S and 12db snr(this changed quikly to 10db). for a couple of days the snr dropped during the day but stayed up at 10db in the evenings,so last night I tried rebooting and the SNR shot up to 18db then settled at 15 for about an hour then went back down to 10. I am asking this as on other posts other people have said it is usual to get more noise at night(so worse snr readings) whereas my readings are the opposite.
sorry about length of post
Cheers
Keith
7 REPLIES
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SNR Fluctuation

Keith

I have experienced the same snr behavious over the last few weeks. My downstream SNR starts at 12 then gradually reduces to 3 or 2 or 1. Invariably, I get a disconnection at this time.

Its currently at 2db.


ADSL Link Downstream Upstream
Connection Speed 4847 kbps 586 kbps
Line Attenuation 38 db 10 db
Noise Margin 2 db 12 db
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SNR Fluctuation

If I were you... remove the lower faceplate bit that the engineer fitted.. this will (should) isolate your extension wiring. Plug a filter into the socket that is revealed, and plug your modem into the filter. See how that behaves - you may have dodgy extension wiring which is picking up RF/electrical interference.
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SNR Fluctuation

The faceplate fitted on the Master socket is the one with separate ADSL and phone socket. I have already tried with the phone ext. pulled out and also gone into the socket behind the faceplate and the same thing is happening to the margin- going from 0 -9 daytime and upto 15db in the evening/early hours. The speed I`m getting is in the 900kbps range with some occassional drops to 250 - 450 kbps. If I didnt know better I`d think I was still on MAX.instead of fixed 1mb.
Cheers
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SNR Fluctuation

Quote
If I didnt know better I`d think I was still on MAX.instead of fixed 1mb

Well there is a way to prove that - what speeds does the netgear report it is synchronising at?
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SNR Fluctuation

Netgear is at 1152kbps and showing U/S 288kbps,so it would point to a fixed 1mb product. It is just the varying noise margins and the many diconnects I was having that was resembling what many Max`d customers are getting that my comment referred to.Just really interested why the noise margin is all over the place. Would this be something that PN would influence. My connection was Interleaved about 10 days ago,something it did not require when I had a perfect connection prior to going onto Max for a short time. Is it possible that some of the controls that Max had might still be influencing my present connection. I`m not a real "techie" so just guessing.
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SNR Fluctuation

It is absolutely essential that you get hold of another modem to compare.

I had a netgear DG834GT that had been used without problem for a year on a 2MB connection. The SNR did vary by up to 10dB but the connection NEVER dropped.

When I got on to Max, the connection of course started to drop when the SNR fell too low since it was targetting 6dB. Alternatively, I would get a 2Mbps connection that was stable.

After changing filters/wiring etc. I retrieved my old modem, a 5 year old DLINK device which gave a rock steady connection at 7.5Mbps instead of the 5Mbps I got with the Netgear. The netgear was also crashing when the latest version of software was loaded so with the 2 year warranty, it was able to be exchanged. Now I have a rock steady (OK its on Plusnet so not that steady) 7.5Mbps connection with a new DG834GT.
Community Veteran
Posts: 1,931
Thanks: 4
Fixes: 1
Registered: 01-08-2007

SNR Fluctuation

Hi

I have the same problem, I have a netgear DG834G v2. I have connected the router to the BT test socket, and got a good SNR of 16dB, rather than the 5-6 I was getting. Tried the night after with the same thing, and got 5dB when connected to the BT test sockets that varied between 4 and 6 dB. I was going to but an ADSL faceplate and Cat5e extention wiring, but I feel if these figures are coming from the test socket, I would be wasting my money. Interestingly, I never lose sync even if the SNR goes down to 1 or 2. Anyone any commentsHuh?Huh