cancel
Showing results for 
Search instead for 
Did you mean: 

downstream margin through the floor, HELP!

Community Veteran
Posts: 1,817
Thanks: 11
Registered: 30-07-2007

downstream margin through the floor, HELP!

Recently my downstream margin has been decreasing to the stage it now rests as 6db . Previous stats were:

ReceiveAttenuation_dB= 44
ReceiveMargin_dB= 28
RxOutputPower_dBm= 0
SendAttenuation_dB= 23
SendMargin_dB= 28
TotalBytesReceived= 11178919
TotalBytesSent= 949601
TotalPacketsReceived= 8394
TotalPacketsSent= 8394
TxOutputPower_dBm= 0
Uptime= 1585
ChannelMode= Fast
Layer1DownstreamMaxBitRate= 1152000
Layer1UpstreamMaxBitRate= 288000
WANAccessType= DSL

Now:

DSL Status : Up
DSL Modulation Mode : GDMT
DSL Path Mode : FAST
Downstream Rate : 2272 Kbps
Upstream Rate : 288 Kbps
Downstream Margin : 6 db
Upstream Margin : 25 db
Downstream Line Attenuation : 45
Upstream Line Attenuation : 24
Downstream Transmit Power : 0
Upstream Transmit Power : 0

This has meant that my potential maxdsl speed has dropped dramatically. is there anything I can do. Not sure if i can ask for bt's help. I still get 2mb but it's slow and I was wondering if these changes in downstream would contribute to that difference.

All help much appreciated.

Alan
7 REPLIES
Community Veteran
Posts: 6,983
Thanks: 8
Registered: 10-04-2007

downstream margin through the floor, HELP!

Looks like something has happened to your line or to your internal wiring as the losses and Signal to Noise Ratio has changed dramatically. Sad

Have you tried connecting the Router or Modem at the Master socket with everything else disconnected? or if you have one of the more modern master sockets then remove the face plate and connect to the test socket inside it.
This removes all other wiring.
Community Veteran
Posts: 14,469
Registered: 30-07-2007

downstream margin through the floor, HELP!

The downstream line attenuation has remained the same (as it should) but the SNR has decreased dramatically.

Note: it would be less than it was anyway due to the increase in line speed (original on 1Mbs, new on 2Mbs) but it should only have decreased by 4 -> 6dB.

Weather conditions can cause wild fluctuations in SNR figues as I have had similar drops (although mine was from 18db down to 3 or 4dB and a line sync problem resulted). I suggest you keep an eye on it and check at various times of the day to see if it is permanently that low or fluctuates beteen the high and low figures.

Try disconnecting your ADSL line for a few minutes and see if that helps. Also try connecting directly to the master socket, and if possible to the test socket behind the lower removable plate on the master socket and see if your SNR improvs. Also try with no other phones plugged in.

Also make sure all phones are connected via an ADSL filter/spliter including any sky/digi boxes that plug into a phone line. Also check other modems, fax machines etc.
Community Veteran
Posts: 1,817
Thanks: 11
Registered: 30-07-2007

downstream margin through the floor, HELP!

I moved the router downstairs on Saturday and the reuslt was no change. I'm a tad miffed as previous result when put into adsl calculator suggested speeds of up to 8mps.

Not sure If rasing a ticket would work as I am still connecting at 2mbps al beit it everything appears to have slowed down. The slow down may be due to general slowness with plus net mentioned elsewhere in the forums.

The snr is low at alla times of day and night at the minute it's at 16 opps 14 now.

Any other ideas.

Alan
Community Veteran
Posts: 14,469
Registered: 30-07-2007

downstream margin through the floor, HELP!

Not sure what to suggest as PN or you can't do anything about the SNR figures, especially when connected directly to the master socket (which I presume you are now). There could be interference locally, or as I suspect the very cold weather has had a detrimental affect on your line.
Community Veteran
Posts: 1,817
Thanks: 11
Registered: 30-07-2007

downstream margin through the floor, HELP!

NO SNR a resonably more acceptable 18

DSL Status : Up
DSL Modulation Mode : GDMT
DSL Path Mode : FAST
Downstream Rate : 2272 Kbps
Upstream Rate : 288 Kbps
Downstream Margin : 17 db
Upstream Margin : 26 db
Downstream Line Attenuation : 44
Upstream Line Attenuation : 24
Downstream Transmit Power : 0
Upstream Transmit Power : 0

Confused. Router has not dropped sync so not sure.
N/A

downstream margin through the floor, HELP!

It does sound either weather or something has somehow happerned to your line, however even if something did happern you will have trouble getting it fixed, I was lucky when something similar happerned to me, however that time roadworks had partially severed my underground line section at that point and also heavily damaged the voice reception on the line which BT must act on (they switched me to an undamaged section and all was actually a little better than before)

But as I have said on the forum once before BT only must provide a line capable of voice and 28k data so there is no requirement to provide any DSL atall and often it means line issues do not warrant any right to get a BT repair done, only chance mostly of getting BT to fix anything is if the actual DSL equipment at the exchange is faulty.

This I personally think is wrong not that they are not compelled to provide a DSL capable line as in a country with some degree of rural seperation they would need so many new exchanges it would be non commecially viable. However if a line once provided a high speed DSL server and ceases to do so this is a fault and should be repaired.

Anyway just my comments, I wish you luck and hope it is just the weather, I personally know my line does not like either thunderstorms or dry, hot and high pressure weather (this also carries radio waves well, radio waves = EMI which phone lines dislike)
Community Veteran
Posts: 1,817
Thanks: 11
Registered: 30-07-2007

downstream margin through the floor, HELP!

Just opened up the main socket as instructed by bt. I managed to deduct that the extension built into the house was the cause of the snr reduction. I've removed the extension from the loop and now the master socket is the only one connected with no second connections behind the faceplate SNR now in 20's.

I'd left everything just connected to the main socket for a week and realised then that the extension could'nt handle the line speed. Roll on 8mb.

Thank goodness for wireless phones or i wouldn't be able to do it.

A