@ NTL Broadband Customers: Do me a quick favour- pls!

72hundred

Hey,

Recently I've been having very bad speeds. I think its to do with interference on the line. There's a way to check this, and I'd really appreciate it if other ntl users could check their results so I can compare my own:

To do it go to 192.168.100.1 (don't worry won't do any damage at all)

Then copy and paste the 2 boxes and reply to this thread (that's my report below)

Receive Power Level: 1.2 dBmV
Transmit Power Level: 57.5 dBmV

I'm pretty sure (almost 100%) that 57.5 is way to high and the reason for my installation problems.

I'm appreciate it if you could do this as I'll be on to tech support in the morning and I want a idea of the service across the ntl network.

Many thanks,
72oo

EDIT; came across this other thread - http://www.boards.ie/vbulletin/showthread.php?t=2055121809 , similar story. But I'd like to see recent reports to see what's going on.

The_Conductor

Receive Power Level 9.8 dBmV

Transmit Power Level 48.0 dBmV

Hmmm- My receive is far higher than yours and my transmit is a good deal lower....... looks like you have a lot of noise? Note: my connection is far from being perfect- but its improved since they put additional repeaters on the line.......

Ps- my modem is a brandnew Scientific Atlanta (the one with the telephone as well as RJ45 ports)

Ps- here are my current upload and download speeds:

Sad Professor

Mine are:

Receive Power Level 3.6 dBmV
Transmit Power Level 46.0 dBmV

My speeds are fine for the most part.

stoneroses

Receive Power Level
0.2 dBmV
Transmit Power Level
56.5 dBmV


Speeds are good.

The_Conductor

Actually- my speeds are pretty crap
At least I don't loose my connection at all..... (any more that is.......)

S.

72hundred

Many many thanks for the quick replies. Kinda confirms what I was thinking.

I'll be on the phone to tech support in the morning, will avoid customer support as I really think they don't understand how anything works.

72hundred

Here's a webpage that relates to ntl in the UK. I imagine its similar tech here:

http://homepage.ntlworld.com/robin.d.h.walker/cmtips/signal.html

Desirable signal levels

For diagnostic purposes, the cable modem can measure and report the Downstream Received Power and the Downstream Signal-to-Noise Ratio (SNR). The SNR is important because if there is too much noise on the cable, the data cannot be decoded correctly, even with downstream power levels within acceptable limits. If the SNR is good enough so that the cable modem is working correctly, the exact power level, even if slightly outside normal ranges, does not matter.
Downstream SNR: should be 30 dB or higher: the higher the better. As the SNR decreases below 30 dB, performance will steadily decrease, and errors will increase. The cable modem might stop working properly if the SNR drops below 23.5 dB.
Downstream Received Power: the DOCSIS specification requires cable modems to function correctly with downstream power levels in the range -15 dBmV to +15 dBmV: power readings at or close to those extremes are likely to be unacceptable. However, when connected to a real-life CATV network, a cable modem might be functional over a narrower range than this. Accordingly, cable ISPs will specify an even narrower target range when commissioning their network: this target range will differ according to ISP.
Provided the Downstream SNR is acceptable, the downstream power should be satisfactory if your cable modem reports a figure either within these specified ranges or close to them.
If a cable modem reports a downstream receive power of exactly 0.0 dB, this means that measurement of downstream power is disabled, and no information is available. In this case, you will need to judge downstream quality by SNR alone.
Upstream Transmit Power: the cable modem's Upstream Transmit Power (or return power) is set by commands from the UBR so that the UBR hears the same signal level from all cable modems on that upstream channel. Because of different cable losses for each cable modem in the area, each cable modem will tend to settle onto a different upstream transmit power level. The better the return path is, the lower the upstream transmit power will be.
The upstream transmit power will lie within the range +8 to +58 dBmV, with many ISPs specifying a target commissioning level below +55 dBmV. Values in the forties are the most common. Many cable modems are unable to transmit any more powerfully than +58 dBmV. One cannot tell how far this is below the figure that the UBR would need to see a strong enough signal at its end to maintain satisfactory performance, so a figure as high as +58 dBmV is normally a sign of an unacceptable return path. If other problem symptoms are also present, an upstream transmit power of +58 dBmV would constitute valid supporting evidence for requesting technical support from a cable ISP.
The upstream SNR can be sensed only at the UBR, so cannot be discovered by end-users.
The external cable infrastructure is affected by weather conditions, so it is normal to see power levels fluctuating slowly with temperature. If your cable signal conditions are marginal, the CM might stop working in certain weather conditions, and recover in others.
However, rapidly fluctuating power levels might be a sign of a failing amplifier in the ISP's network, or a bad cable connection, and should normally be investigated.

EDIT: In case the above is too texty here's the most important info:

Downstream should be -2.5 to +2.5
Upstream should be +8 to +55

LimerickGuy2009

Here are mine :
Receive Power Level : 7.3dBmV
Transmit Power Level : 35.7dBmV

I've been have slow speeds since i joined Chorus/Ntl over 4 weeks ago.

They have just added a new server in Limerick and have discovered that they need to replace cable on some nodes or so they say.

Tazzle

Receive Power Level
3.6 dBmV

Transmit Power Level
34.5 dBmV

Slutmonkey57b

Receive: -10.1 dBmV

Transmit: 54.0 dBmV

Near ballyogan

Slutmonkey57b

Receive: -10.1 dBmV

Transmit: 54.0 dBmV

Near ballyogan

Voipjunkie

Recieve power level -913.2 dBmV
Transmit power level 8.3 dBmV

And no that is not a typo it really said -913.2

Btw mine is knackered has been since last week outage in Donaghmede they claim to have fixed but they now say it is my modem

guil

in newbridge
Receive Power Level
5.7 dBmV

Transmit Power Level
53.7 dBmV

Clover

In Blanchardstown with a new Scientific Atlanta cable modem.

Receive Power Level
-5.7 dBmV
Transmit Power Level
49.0 dBmV

garytuohy

Power Level
5.9 dBmV

Signal to Noise Ratio
38.0 dB

considering whatever they dig up in the ground is right outside my house...I have been told I am the only one in the area who will actually get 100% signal

I don't know how true that is actually cause I don't know how the Cable network works.

But engineer checked at it was 100% but I barely get a 3rd of the speeds and the phone keeps dropping

72hundred

Many thanks for all the replies. I'll post up the results of the phone call with tech support when I get thru.

Moriarty

I've no idea what thresholds UPC use internally, but a receive power between -10dB and +10dB and transmit power below 55dB with an SNR of >25dB is generally fine on a docsis network.

If you're seeing problems when your connection is inside those limits, it will probably be an IP issue of some sort - more often than not IP contention at the local CMTS.

faoile@n

I have 20mb and have a rock solid connection. It hasn'tgone down for the 4 months i've had it.

Receive Power Level 0.1 dBmV
Transmit Power Level 46.0dBmV

dodzy

I'm at -0.3dbmv RPL and 43.5 TPL. I had "engineers" *cough* out 7 times. Some really unknowledgeable sorts. I mean piss poor. I was at a constant 61dbmv on TPL. Way too high. Anyway, eventually a guy turned up - I was sceptical as usual. He asked for PC access. Granted. Immediately said that TPL was too high and thst I would always experience periodical dropping of supply. He whipped off the access cover outside the front of the house, disconnected a piece of kit, said it was faulty and that he'd be back in 2 hrs - . I went to work. The wife called me. Put me on to him. He told me all was well .That was 6 weeks ago. Hasn't flinched since. He obviously knew his sh*t.

To simplify: Persevere & demand the service that you are paying for...... (but in a nice manner ;-)

Receive Power Level
4.4 dBmV
Transmit Power Level
54.5 dBmV
Signal to Noise Ratio
39.7 dBmV

I'm in Drumcondra. I was a bit worried about the transmit power being so high but it seems to be working fine. I suppose once it's not actually at 57/58 it's probably ok.

Loveless

Downstream Power Level -7.9 dBmV
Upstream Power 48.7 dBmV

72hundred

After: 30 min's on phone. I've a tech call out for Thursday morning. Hopefully will replace something locally and get this sorted quickly.