Topic 'How do my Signals Look?' in forum 'Cable users' - dslreports.com

Re: How do my Signals Look?

Sun, 09 Dec 2012 10:52:33 EDT

sectvfreak posted : thanks, not bad for a rural area on the very last house of a 4 mile feeder line the fiber ends about .8 miles from my house the node is 1.5 away.. upstream is ok also???

Re: How do my Signals Look?

Wed, 05 Dec 2012 23:28:52 EDT

scififan68 posted :

said by sectvfreak:

heres my signal on service electric of Lehigh Valley, PA how are they ? still on Docsis 2.0 supposely 3.0 is coming out soon they did frequency change recently any feedback appreciated thanks

Downstream
Frequency to tune to: Hz
Scanning start frequency: 999000000 Hz
Channel Frequency: 399001709 Hz
Modulation: 256 QAM
Signal strength: 2.6581 dBmV
Signal noise ratio: 37.356 dB

Upstream
Channel Id: 3
Upstream Frequency: 23000000 Hz
Upstream bandwidth: 3200000 Hz
Transmission signal strength: 41.5000 dBmV

That signal is almost perfect, 0dBmV may be the best, but 2dBmV is great.

Re: How do my Signals Look?

Wed, 05 Dec 2012 21:59:23 EDT

sectvfreak posted : heres my signal on service electric of Lehigh Valley, PA how are they ? still on Docsis 2.0 supposely 3.0 is coming out soon they did frequency change recently any feedback appreciated thanks

Downstream
Frequency to tune to: Hz
Scanning start frequency: 999000000 Hz
Channel Frequency: 399001709 Hz
Modulation: 256 QAM
Signal strength: 2.6581 dBmV
Signal noise ratio: 37.356 dB

Upstream
Channel Id: 3
Upstream Frequency: 23000000 Hz
Upstream bandwidth: 3200000 Hz
Transmission signal strength: 41.5000 dBmV

Re: How do my Signals Look?

Sat, 01 Dec 2012 22:09:10 EDT

TheWiseGuy posted : Here are a couple of good links explaining Correctables and Uncorrectables. While both of these links tend to focus on the Upstream, the principle is the same on the downstream.

»volpefirm.com/blog/troubleshooti···-errors/

»www.cable360.net/ct/sections/col···938.html

Downstream Correctables and Uncorrectables both have data corrupted by noise on the downstream but the difference is that the corruption is less in a Correctable so it can be fixed with FEC(Forward Error Correction)

From the second article

What’s an acceptable percentage or number of codeword errors? That’s definitely an “it depends” question, but let’s start with an ideal goal: No correctable or uncorrectable codeword errors at all in either the downstream or the upstream. One could argue that, in a network performing so well that there are no codeword errors of any kind in the QAM signals, it would be possible to take advantage of eliminating FEC overhead altogether and picking up a little more throughput per channel. Of course, this goal is unrealistic.

The percentage that is important is the number of uncorrectables to octets(codewords). Your percentage is very low. Of course the overall percentage can be misleading if something has suddenly gotten worse and prior data disguises the recent percentage.
--
Warning, If you post nonsense and use misinformation and are here to argue based on those methods, you will be put on ignore.

Re: How do my Signals Look?

Sat, 01 Dec 2012 15:29:44 EDT

beachintech posted :

said by Couriant:

said by JeepMatt:

That final column is Uncorrected Errors - really shouldn't see much of anything there - that's what i was concerned with.

I concur. The first download stream has uncorrectables at 120% more than the corrected... that is not good, the others are fine though. As to the US Power, that should be fine also, it means the modem doesn't need to 'shout' as loud to be heard by the CMTS.

You are correct, but that is still too low to get up and over the noise floor. Something in the plant is out of balance.
--
Ex-Comcast Tech at the Beach. I speak for myself, not my former employer.

Re: How do my Signals Look?

Sat, 01 Dec 2012 13:10:14 EDT

TheWiseGuy posted : Your uncorrectables as a percent of Octets is extremely low. Unless it was a higher percent it is unlikely to be a problem. Now if they have just started to occur then there could be a problem. You could reset the counters and see if the percentage goes up.
--
Warning, If you post nonsense and use misinformation and are here to argue based on those methods, you will be put on ignore.

Re: How do my Signals Look?

Fri, 30 Nov 2012 18:58:33 EDT

Couriant posted :

said by JeepMatt:

That final column is Uncorrected Errors - really shouldn't see much of anything there - that's what i was concerned with.

Re: How do my Signals Look?

Wed, 21 Nov 2012 18:48:07 EDT

JeepMatt posted : That final column is Uncorrected Errors - really shouldn't see much of anything there - that's what i was concerned with. I've had less than 100 errors on my system over an 18 day period - that's why when i saw yours at 30,000+ i was concerned.

Downstream, SNR "could" be a little higher, but that and the Power Levels are good.

Like the other poster mentioned, your upstream power at 28 is REALLY low...could cause some issues down the road for you. But, if you're getting what you want - just keep an eye on things.
--
"ONE team - ONE city - ONE dream!!"

Re: How do my Signals Look?

Wed, 21 Nov 2012 18:13:45 EDT

Gib4500 posted : yea on my connection i'v actually got an 18db upstream power level. My isp is crystal broadband networks. I do get random disconnects too. I'm trying to get them to fix it but i'm getting frustrated.

Re: How do my Signals Look?

Tue, 20 Nov 2012 10:24:35 EDT

hyelton posted : Not really seeing any issues at all. I`m the only one thats on the 24 meg service. the rest are 12meg and 6 meg. But the line that runs to my modem is a direct line to the power line always has been since 2005 no cable tv or anything.

Re: How do my Signals Look?

Mon, 19 Nov 2012 15:56:07 EDT

JeepMatt posted : Also,
You must be a on small system - really surprised to see they used the entire FM frequency band (93-105) for your internet. That's prone to a lot of interference - not surprised you're seeing that high of a # in the error blocks.
--
"ONE team - ONE city - ONE dream!!"

Re: How do my Signals Look?

Mon, 19 Nov 2012 03:13:36 EDT

scififan68 posted : Your downstream SNR is a bit low and you have some Correcteds and Uncorrectables. Your upstream is way too low, its recommended to be at ~40dBmV and yours is 28! If your internet is not working correctly, I wouldn't be surprised. You need to check some wiring, make sure your modem is on the first splitter and if it is then you need to have your isp come out and fix that upstream!

How do my Signals Look?

Sat, 17 Nov 2012 23:12:49 EDT

hyelton posted : Okay so I`m the FIRST and ONLY person here at the moment with the local Provider Northland Cable that has the 24 meg package and with the ONLY DOSIS 3 modem how does my signals look?

Downstream

DCID Freq Power SNR Modulation Octets Correcteds Uncorrectables
Downstream 1 23 105.00 MHz 5.17 dBmV 35.60 dB 256QAM 20466821136 18102 21688
Downstream 2 21 93.00 MHz 5.62 dBmV 34.93 dB 256QAM 20023745684 881781 29029
Downstream 3 22 99.00 MHz 5.38 dBmV 35.42 dB 256QAM 19459003443 242364 32928
Downstream 4 24 111.00 MHz 4.56 dBmV 35.25 dB 256QAM 20261987964 622470 29670

Upstream

UCID Freq Power Channel Type Symbol Rate Modulation
Upstream 1 4 29.00 MHz 28.68 dBmV DOCSIS1.x (TDMA) 2560 kSym/s 16QAM