Home News Forum Articles
  Welcome back Join CF
You are here You are here: Home | Forum | 55 DbmV upstream power level


You are currently viewing our boards as a guest which gives you limited access to view most of the discussions, articles and other free features. By joining our Virgin Media community you will have full access to all discussions, be able to view and post threads, communicate privately with other members (PM), respond to polls, upload your own images/photos, and access many other special features. Registration is fast, simple and absolutely free so please join our community today.


Welcome to Cable Forum
Go Back   Cable Forum > Virgin Media Services > Virgin Media Internet Service

55 DbmV upstream power level
Reply
 
Thread Tools
Old 12-01-2009, 22:00   #1
Steve Day
cf.member
 
Join Date: Feb 2006
Posts: 33
Steve Day is on a distinguished roadSteve Day is on a distinguished road
55 DbmV upstream power level

On wednesday i have a tech coming out to have a look at my connection whose upstream jumped from 50 to 55 last week. currently it is stable but i was just wondering what i can expect the guy to do about it?

I have no splitters just a direct cable from the modem to my incoming cable box, it is the only cable connection i have.

just out of interest

Steve
Steve Day is offline   Reply With Quote
Advertisement
Old 12-01-2009, 22:04   #2
Stabhappy
Inactive
 
Join Date: Sep 2008
Location: South Wales
Age: 25
Services: XXL BB + M Phone
Posts: 485
Stabhappy is just really niceStabhappy is just really niceStabhappy is just really niceStabhappy is just really niceStabhappy is just really niceStabhappy is just really nice
Send a message via MSN to Stabhappy
Re: 55 DbmV upstream power level

It could be effecting your service so he will fit a device to lower the power level.
Stabhappy is offline   Reply With Quote
Old 12-01-2009, 22:54   #3
Ignitionnet
MSc student and Pro PITA
 
Ignitionnet's Avatar
 
Join Date: Jun 2008
Location: Leeds, West Yorkshire
Age: 36
Posts: 10,896
Ignitionnet has a pair of shiny starsIgnitionnet has a pair of shiny stars
Ignitionnet has a pair of shiny starsIgnitionnet has a pair of shiny starsIgnitionnet has a pair of shiny starsIgnitionnet has a pair of shiny starsIgnitionnet has a pair of shiny starsIgnitionnet has a pair of shiny starsIgnitionnet has a pair of shiny starsIgnitionnet has a pair of shiny starsIgnitionnet has a pair of shiny starsIgnitionnet has a pair of shiny starsIgnitionnet has a pair of shiny starsIgnitionnet has a pair of shiny starsIgnitionnet has a pair of shiny starsIgnitionnet has a pair of shiny starsIgnitionnet has a pair of shiny starsIgnitionnet has a pair of shiny starsIgnitionnet has a pair of shiny starsIgnitionnet has a pair of shiny starsIgnitionnet has a pair of shiny stars
Re: 55 DbmV upstream power level

How's he going to fit something to the modem to lower the upstream transmit power level Stab?

If he can't find anything obvious causing the problem he might have to get a network tech in. With a bit of luck it'll be something simple like a connection not done properly.
Ignitionnet is offline   Reply With Quote
Old 12-01-2009, 23:28   #4
moaningmags
cf.mega poster
 
Join Date: Aug 2007
Location: Scotland
Age: 41
Services: 20mb, Tv, Phone
Posts: 2,849
moaningmags has a bronze arraymoaningmags has a bronze arraymoaningmags has a bronze array
moaningmags has a bronze arraymoaningmags has a bronze arraymoaningmags has a bronze arraymoaningmags has a bronze arraymoaningmags has a bronze arraymoaningmags has a bronze arraymoaningmags has a bronze arraymoaningmags has a bronze arraymoaningmags has a bronze arraymoaningmags has a bronze array
Re: 55 DbmV upstream power level

He may well fit an attenuator between the coax and the modem.
moaningmags is offline   Reply With Quote
Old 12-01-2009, 23:34   #5
Stabhappy
Inactive
 
Join Date: Sep 2008
Location: South Wales
Age: 25
Services: XXL BB + M Phone
Posts: 485
Stabhappy is just really niceStabhappy is just really niceStabhappy is just really niceStabhappy is just really niceStabhappy is just really niceStabhappy is just really nice
Send a message via MSN to Stabhappy
Re: 55 DbmV upstream power level

I thought that's what was done when power levels were incorrect? I guess it makes logical sense that it's only possible to boost the signal levels.
Stabhappy is offline   Reply With Quote
Old 12-01-2009, 23:40   #6
moaningmags
cf.mega poster
 
Join Date: Aug 2007
Location: Scotland
Age: 41
Services: 20mb, Tv, Phone
Posts: 2,849
moaningmags has a bronze arraymoaningmags has a bronze arraymoaningmags has a bronze array
moaningmags has a bronze arraymoaningmags has a bronze arraymoaningmags has a bronze arraymoaningmags has a bronze arraymoaningmags has a bronze arraymoaningmags has a bronze arraymoaningmags has a bronze arraymoaningmags has a bronze arraymoaningmags has a bronze arraymoaningmags has a bronze array
Re: 55 DbmV upstream power level

They can fit attenuators to boost or reduce the power levels.

I stand corrected, attenuators are for downstream power levels and SNR.
The friend who corrected me knows their stuff, so I'll take their word for it.


Another edit after quick tutorial from said friend, the upstream can be adjusted by an attenuator.
This would usually happen at the cab, but if low downstream SNR is causing the upstream power level to increase to be heard by the ubr, fitting an attenuator would fix the SNR issue, lowering the upstream power level.

Last edited by moaningmags; 13-01-2009 at 00:24.
moaningmags is offline   Reply With Quote
Old 12-01-2009, 23:51   #7
Stabhappy
Inactive
 
Join Date: Sep 2008
Location: South Wales
Age: 25
Services: XXL BB + M Phone
Posts: 485
Stabhappy is just really niceStabhappy is just really niceStabhappy is just really niceStabhappy is just really niceStabhappy is just really niceStabhappy is just really nice
Send a message via MSN to Stabhappy
Re: 55 DbmV upstream power level

Mmm. As I thought.
Stabhappy is offline   Reply With Quote
Old 13-01-2009, 00:35   #8
moaningmags
cf.mega poster
 
Join Date: Aug 2007
Location: Scotland
Age: 41
Services: 20mb, Tv, Phone
Posts: 2,849
moaningmags has a bronze arraymoaningmags has a bronze arraymoaningmags has a bronze array
moaningmags has a bronze arraymoaningmags has a bronze arraymoaningmags has a bronze arraymoaningmags has a bronze arraymoaningmags has a bronze arraymoaningmags has a bronze arraymoaningmags has a bronze arraymoaningmags has a bronze arraymoaningmags has a bronze arraymoaningmags has a bronze array
Re: 55 DbmV upstream power level

Steve

What is your downstream SNR?
moaningmags is offline   Reply With Quote
Old 13-01-2009, 00:45   #9
Steve Day
cf.member
 
Join Date: Feb 2006
Posts: 33
Steve Day is on a distinguished roadSteve Day is on a distinguished road
Re: 55 DbmV upstream power level

all other values seem fine.

downstream

SNR 40
power level 7db

the upstream power was until november in the high 40s, then it slid up to 50/51 then after an outage which took down my entire are last week it leapt up to 55 and has stayed there. but at the weekend i had no connection for over 12 hours with "ranging errors" filling my modem logs.

Steve
Steve Day is offline   Reply With Quote
Old 13-01-2009, 00:50   #10
moaningmags
cf.mega poster
 
Join Date: Aug 2007
Location: Scotland
Age: 41
Services: 20mb, Tv, Phone
Posts: 2,849
moaningmags has a bronze arraymoaningmags has a bronze arraymoaningmags has a bronze array
moaningmags has a bronze arraymoaningmags has a bronze arraymoaningmags has a bronze arraymoaningmags has a bronze arraymoaningmags has a bronze arraymoaningmags has a bronze arraymoaningmags has a bronze arraymoaningmags has a bronze arraymoaningmags has a bronze arraymoaningmags has a bronze array
Re: 55 DbmV upstream power level

That's a very healthy SNR, so an attenuator won't fix it.
Must be something in the cab causing it, a tech visit is needed, he should check the modem, which one is it?
He should check the cabling, have you made sure the white coaxial cable is screwed in tight and not loose in any way.
If they check out, he should then check the cab at the end of the street.
moaningmags is offline   Reply With Quote
Old 13-01-2009, 03:28   #11
Steve Day
cf.member
 
Join Date: Feb 2006
Posts: 33
Steve Day is on a distinguished roadSteve Day is on a distinguished road
Re: 55 DbmV upstream power level

there is a tech coming on wednesday actually.
I created this thread because i knew that here i could get a realistic appraisal of what i should be expecting him to check and what i could check myself.

the modem is 3 year old motorola sb5100 which up to now has been fine but it has afterall been on virtually 24/7 for just over 3 years.

i have reconnected the coax at the modem end and tried it with and without the -6db attenuator that was fitted last year to drop my downstream power level to 8db (i was running at 14db).

Steve
Steve Day is offline   Reply With Quote
Old 13-01-2009, 08:59   #12
Ignitionnet
MSc student and Pro PITA
 
Ignitionnet's Avatar
 
Join Date: Jun 2008
Location: Leeds, West Yorkshire
Age: 36
Posts: 10,896
Ignitionnet has a pair of shiny starsIgnitionnet has a pair of shiny stars
Ignitionnet has a pair of shiny starsIgnitionnet has a pair of shiny starsIgnitionnet has a pair of shiny starsIgnitionnet has a pair of shiny starsIgnitionnet has a pair of shiny starsIgnitionnet has a pair of shiny starsIgnitionnet has a pair of shiny starsIgnitionnet has a pair of shiny starsIgnitionnet has a pair of shiny starsIgnitionnet has a pair of shiny starsIgnitionnet has a pair of shiny starsIgnitionnet has a pair of shiny starsIgnitionnet has a pair of shiny starsIgnitionnet has a pair of shiny starsIgnitionnet has a pair of shiny starsIgnitionnet has a pair of shiny starsIgnitionnet has a pair of shiny starsIgnitionnet has a pair of shiny starsIgnitionnet has a pair of shiny stars
Re: 55 DbmV upstream power level

Quote:
Originally Posted by moaningmags View Post
Another edit after quick tutorial from said friend, the upstream can be adjusted by an attenuator.
This would usually happen at the cab, but if low downstream SNR is causing the upstream power level to increase to be heard by the ubr, fitting an attenuator would fix the SNR issue, lowering the upstream power level.
This confuses me a bit how a bad downstream SNR would cause the upstream transmit power level to increase so I'll look into it a bit more and speak to someone who will know, have seen bad downstream SNR and it did not appear to cause modems to increase their transmit power.

Thank you for the information!
Ignitionnet is offline   Reply With Quote
Old 13-01-2009, 09:06   #13
caph
cf.geek
 
Join Date: Jun 2007
Posts: 563
caph is a name known to allcaph is a name known to allcaph is a name known to allcaph is a name known to allcaph is a name known to allcaph is a name known to allcaph is a name known to allcaph is a name known to all
Re: 55 DbmV upstream power level

I've been told by an engineer that my local increase in upstream power is being caused by my "exchange" being upgraded to 50Mb.
caph is offline   Reply With Quote
Old 13-01-2009, 19:16   #14
Ignitionnet
MSc student and Pro PITA
 
Ignitionnet's Avatar
 
Join Date: Jun 2008
Location: Leeds, West Yorkshire
Age: 36
Posts: 10,896
Ignitionnet has a pair of shiny starsIgnitionnet has a pair of shiny stars
Ignitionnet has a pair of shiny starsIgnitionnet has a pair of shiny starsIgnitionnet has a pair of shiny starsIgnitionnet has a pair of shiny starsIgnitionnet has a pair of shiny starsIgnitionnet has a pair of shiny starsIgnitionnet has a pair of shiny starsIgnitionnet has a pair of shiny starsIgnitionnet has a pair of shiny starsIgnitionnet has a pair of shiny starsIgnitionnet has a pair of shiny starsIgnitionnet has a pair of shiny starsIgnitionnet has a pair of shiny starsIgnitionnet has a pair of shiny starsIgnitionnet has a pair of shiny starsIgnitionnet has a pair of shiny starsIgnitionnet has a pair of shiny starsIgnitionnet has a pair of shiny starsIgnitionnet has a pair of shiny stars
Re: 55 DbmV upstream power level

Quote:
Originally Posted by moaningmags View Post
Another edit after quick tutorial from said friend, the upstream can be adjusted by an attenuator.
This would usually happen at the cab, but if low downstream SNR is causing the upstream power level to increase to be heard by the ubr, fitting an attenuator would fix the SNR issue, lowering the upstream power level.
I had another thought about this.

If bad downstream SNR were causing issues with upstream it would be because the modem were not seeing the periodic station maintenance responses from the uBR / CMTS, so it would increase transmit power thinking it was not being heard. When it did actually get a response from the CMTS it would be along the lines of 'Oi stop shouting, drop your transmit power down xdBmV' so I can't really see how it would reduce Tx power long term.

What it might resolve is large numbers of power adjustments due to the modem not seeing the range response from the CMTS and hence incrementing transmit power by the DOCSIS standard amount, however if the downstream path is so munted that the modem is missing large amounts of range responses and periodic station maintenances from the CMTS the upstream power is a total non-issue.

A connection that would suffer issues like this would be very, very broken indeed and upstream Tx power would be the least of worries on a connection like this. It would likely be too busy losing QAM sync on the downstream to be bothered what the upstream is doing.

---------- Post added at 18:16 ---------- Previous post was at 18:14 ----------

Quote:
Originally Posted by caph View Post
I've been told by an engineer that my local increase in upstream power is being caused by my "exchange" being upgraded to 50Mb.
That sounds like BS to me. Doesn't make any sense at all that your upstream power would need to rise to accomodate 50Mbit and the DOCSIS 3 overlay.
Ignitionnet is offline   Reply With Quote
Old 13-01-2009, 20:29   #15
caph
cf.geek
 
Join Date: Jun 2007
Posts: 563
caph is a name known to allcaph is a name known to allcaph is a name known to allcaph is a name known to allcaph is a name known to allcaph is a name known to allcaph is a name known to allcaph is a name known to all
Re: 55 DbmV upstream power level

Quote:
Originally Posted by Broadbandings View Post
That sounds like BS to me. Doesn't make any sense at all that your upstream power would need to rise to accomodate 50Mbit and the DOCSIS 3 overlay.
Sounds like it could be BS to me too but the only logical conclusion to that is that service engineers deliberately lie to customers to fob them off. It's possible but it leaves a bad taste in my mouth. His words were more along the lines of - they're up to their neck in it and the power levels are all over the place and will be until they're finished.

---------- Post added at 19:29 ---------- Previous post was at 18:50 ----------

Quote:
Originally Posted by Broadbandings View Post
If bad downstream SNR were causing issues with upstream it would be because the modem were not seeing the periodic station maintenance responses from the uBR / CMTS, so it would increase transmit power thinking it was not being heard. When it did actually get a response from the CMTS it would be along the lines of 'Oi stop shouting, drop your transmit power down xdBmV' so I can't really see how it would reduce Tx power long term.

What it might resolve is large numbers of power adjustments due to the modem not seeing the range response from the CMTS and hence incrementing transmit power by the DOCSIS standard amount, however if the downstream path is so munted that the modem is missing large amounts of range responses and periodic station maintenances from the CMTS the upstream power is a total non-issue.

A connection that would suffer issues like this would be very, very broken indeed and upstream Tx power would be the least of worries on a connection like this. It would likely be too busy losing QAM sync on the downstream to be bothered what the upstream is doing.
Sorry to jump thread but you are almost exactly describing my current UCD problem apart from the downstream problem.

My event log is showing continual critical errors of "Started Unicast Maintenance Ranging - No Response received" followed by the UDC message. And my upstream power levels keeps getting higher and higher (hit 60db tonight). The only thing is my downstream power is 0.6 and my downstream SNR is a healthy 36.3. Can you think of any reason why my modem keeps shouting but not getting a reply?
caph is offline   Reply With Quote
Reply


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Google Search




All times are GMT +1. The time now is 18:18.


Server: titan.cableforum.co.uk
Powered by vBulletin® Version 3.8.9 Beta 1
Copyright ©2000 - 2014, vBulletin Solutions, Inc.


SEO by vBSEO 3.3.2