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Signal from Comcast interrupted throughout the day using a splitter

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Last response: in Components
August 16, 2011 7:50:05 PM

Signal fm Comcast continues to be interrupted throughout the day. Using new Ideal 1 Ghz splitter 4 dB output each to modem and tv. Modem connected to router. Router connected to CPU. This is the third splitter I've tried. System works fine w/o splitter. Any options besides doing without a splitter and tv?

More about : signal comcast interrupted day splitter

August 16, 2011 8:33:55 PM

Cable internet lines do hate to be split. Out of all the outlets in the house you'll see any good cable tech do everything possible to dedicate the internet line to bypass splitters. The best option is usually to install an additional outlet for the TV if that is an option for you, otherwise you're going to keep dealing with issues.
August 16, 2011 9:03:15 PM

With a cable modem look for a high frequency bandwidth splitter
I use a 2500mhz (2.5 ghz) splitter I got from Home Depot
but as MrYoink correctly states
having too many splitters and couplers is detrimental to the cable modem/phone line
cable tv needs less DBs of signal compared to a cable/phone line modem

Try entering in your Internet address bar
This should take you to the modems internal menu/stats screen
look for status screen
it will show you the Signal To Noise ration measured in decibels
On mine it gets about 35-36 dbs
which I find to be borderline
My cable install suffers from too many splits and couplers itself so
I have been dealing with this issue myself

try to use high frequency splitters

use the better quality cabling where you can and try to keep the runs short

if it is possible to run one two splitter where the cable comes in then
one leg to the cable modem and one to the rest of the TVs

make sure all connections running to the cable modem are tight
use pliers if need be to tighten

I was up to 5 a.m. dealing with just this problem
I managed to get my service back online but I am monitoring it by checking cable modem internal software
I might have to run a new line which of course I am trying to avoid since I am lazy :) 
Related resources
August 16, 2011 9:07:28 PM

jsut to show you
I copy/pasted the signals strength from my Arris modem menu

Freq/Power: 711.000 MHz -9 dBmV
Signal to Noise Ratio: 35 dB
Modulation: QAM256

Freq/Power: 29.400 MHz 54 dBmV
Channel Type: DOCSIS 2.0 (ATDMA)

Symbol Rate: 5120 kSym/sec

Modulation: QAM64

if you notice I am doing okay since I am running at DOCSIS 2.0 for up signal

for the Residential Performance Internet package you want to be running D 2.0

I know that is more than just SNR signal that matters that frequency at top 7xx mhz with the DBM number matters but I have to research what that means

I think that is a carrier signal

August 16, 2011 9:33:11 PM

okay been studying

using my stats as an example

Freq/Power: 711.000 MHz -9 dBmV (-power level-between -8 and +8 ideally)
Signal to Noise Ratio: 35 dB (SNR ratio-above 30 is good)
Modulation: QAM256 refer to your owners manual but for my Arris this is the highest level for mine

Freq/Power: 29.400 MHz (Head signal-above 29 is good) 54 dBmV (signal to provider-lower 55 is good)
Channel Type: DOCSIS 2.0 (ATDMA) (D 2.0 is for residential Performance internet-there are better DOCSIS standards for business customers)

Symbol Rate: 5120 kSym/sec

Modulation: QAM64
August 16, 2011 9:33:39 PM

Is this all that you have, one modem and one TV?
In my house we have a lot of old wiring and splitters. It started as just 2 TV's but we have added outlets and splitters and so forth over the years, a lot of it installed by Comcast. When my cable started acting up I studied the wiring and finally realized that the signal went through several splitters before getting to the modem. For some reason the cable modem wants a much stronger signal than the TV's do. I rearranged some wiring according to recommendations on the internet. In general you want to take the incoming signal and split it once with a 2-way splitter. Send one of the splitter outputs direct to the cable modem, send the other splitter output to everything else in your house. This signal can be split again, but minimize the number of splitters.
Another factor is the type of cable that you have. Our old wiring is a mixture of different cables. I bought a 500' spool of new RG6 cable and rewired my entire house.
August 16, 2011 9:50:06 PM

The main issue when comes to cable modem internet, is based on how cable systems weren't truly designed with 2-way communication in mind. So the balance between downstream and upstream signals is very touchy and why the internet has so many issues when being split as raising 1 signal drops another etc.

If you go into the modem status at the as mentioned you are ideally looking for signal in these ranges:
Downstream power level (Receive): -10 to +10
Upstream (Transmit): 35-52
Carrier/Noise Ratio: 35 and above

Check your signals without the splitter and compare them with it and at least then you'll get an idea as to the problem in your scenario.
August 16, 2011 9:58:23 PM

^+1 MrYoink Great Advice!

MrYoink If I can pick your brain with a few questions in a PM
please let me know if that is okay :) 
August 16, 2011 10:23:26 PM

Im a cable HSD tech and your main problem is the high return. 54 db is very high. The advice given for a dedicated line is spot on. You want the service line going to a 2 way. one leg feeds the modem and the other leg feeds the larger splitter feeding the restof the house. Docsis 3.0needs even better signalof 50 dB or lower somight as well start getting prepared!
August 16, 2011 11:05:08 PM

thank you VictorF3

From my reading my numbers are borderline decent
but I do want better numbers

just with a two family 150 year old house with lathe and plaster walls
running line is a nightmare
I am thinking about going thru the basement up into the modem room
for now I have a splitter I want to upgrade
I have it split to go to my tv tuner in tower so a higher pass splitter might helps
since it is just a 1100 mhz splitter now

OP sorry for hijacking a little
really would love to see your stats from your cable modem

this is my results link
August 16, 2011 11:05:40 PM

August 17, 2011 12:18:39 AM

When I go to the address, I don't find the Downstream/Upstream Carrier/Noise Ratio numbers that you mentioned should be there.

I get Cable Modem Info such as DOCSIS 1.0/1.1/2.0 compliant
Mac Address; IP Address; Serial Number; Boot Code Version; Software Version; Hardware Version but no numbers.
August 17, 2011 12:41:13 AM

on my modem it has a tabbed menu screen
higher up on the page
see if there is something that says something to the effect of

what make and model of modem?
August 17, 2011 12:42:27 AM

whatever you do DO NOT post your mac address!
on the forum
bad things can happen
August 17, 2011 12:50:59 AM

I completed the ping test. First it was an F, then I tested again and got an A, with no packet loss, ping @ 38ms, jitter @ 3ms. Not sure what happened the first time.

I have a ubee modem model # U10C018.89
August 17, 2011 1:02:01 AM

I looked again and there is no status tab

August 17, 2011 1:13:29 AM

if it possible to get a higher frequency splitter
then try that
what country are you in?
try to get something like a 2500 mhz splitter
usually be labeled digital splitter
a 1ghz is really low
that is fine for cable but you need a higher freq for cable modem
hopefully VictorF3 or MrYoink can back me up with that advice

your ping test sounds good
let me see what I can dig up on the ubee modem
August 17, 2011 1:24:39 AM

well it is also an Ambit modem with same model number
I rean across several forums where people had their performance numbers
keep digging around that screen and see what you came up with
it has to show the upstream and downstream stats somewhere
August 17, 2011 1:42:50 AM

Thanks for the insight king smp and others. There are alot of suggestions here which I will dig through and try over the next several days...wish me luck!
August 17, 2011 4:54:18 AM

please report back with results :) 
August 17, 2011 8:20:39 AM

You can send me a message if you still wish King smp, I usually glance at Toms a couple times a day so bear with me if takes a bit to respond though. I was a level 2 data tech at one point in time lol
August 24, 2011 12:06:58 PM

Best answer selected by carpeng.
a b x TV
January 28, 2012 3:02:27 PM

This topic has been closed by Mousemonkey