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Internet through only a specific coax cable?

Frequent Visitor

Internet through only a specific coax cable?

Hello,

 

It appears that my house has a single incoming cable/internet connection that feeds three cables throughout my house. It appears that these are all the same type of coax cable.

 

I currently have one of these cables going to my Comcast modem/router. The internet works through this cable. When I move the modem/router to another cable in my house, the internet does not work.

 

At the point where the incoming cable is split from one to three, I swaped the cable that is working from its current port on the splitter (let's call it port A) with another cable that isn't working on its current port on the splitter (let's call it port to see if it is the splitter that has an issue. When I do that, the cable from A now goes to a differnt room in my house but still does not provide an internet connection through the modem/router, and the cable from B goes to the current room in my house that currently does provide an internet connection through the modem/router. In other words, I believe both cables are working but when they are swapped on the ports on the splitter, the same room is able to get internet while the other room still cannot get internet.

 

Any thoughts and suggestions on this issue?

 

Thanks!

 

Will

Official Employee

Re: Internet through only a specific coax cable?

If its possible to follow the 2nd line and see if its damaged at all,or not connected or behind the wall plate and see if its connected. Also, if you don't have any other services bypass the splitter and see
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Silver Problem Solver

Re: Internet through only a specific coax cable?

I think you can buy a new splitter at BestBuy, Radio Shack or a Comcast store.

or you can call comcast and have them send out a tech.

Diamond Problem Solver

Re: Internet through only a specific coax cable?

FWIW, don't buy any garbage splitters at big box stores or Radio Shack Gold gold colored junk. 

 

Here are some quality splitters that Comcast actually uses in different market areas;

Antronix CMC2002H 2-Way Splitter: http://www.amazon.com/Antronix-CMC2002H-2-Way-Splitter/dp/B001E4OH1E

Regal 2 WAY 1 GHZ SPLITTER: http://www.amazon.com/DIG702867-Regal-WAY-GHZ-SPLITTER/dp/B0018BQMUM/ref=sr_1_2?s=electronics&ie=UTF...

Extreme Broadband BDS102H 2-Way Digital Coax Splitter: http://www.amazon.com/EXTREME-DIGITAL-PERFORMANCE-CABLE-SPLITTER/dp/B007YV0UQW

http://www.cencom94.com/subpage21.html

Silver Problem Solver

Re: Internet through only a specific coax cable?

In some areas big box stores like Best Buy have a Comcast Kiosk with a Comcast Employee who will sell Comcast approved devices.

Diamond Problem Solver

Re: Internet through only a specific coax cable?

Fair enough JamesR. Smiley Happy

 

From what I understand, these "kiosks" are steadily being closed down.

Silver Problem Solver

Re: Internet through only a specific coax cable?

Well Old Guys don't get out and about all that often but last time i was at the Best Buy local to me, The Comcast Guy was alive and well and doing his thing.

Frequent Visitor

Re: Internet through only a specific coax cable?

I have an update to this issue. The cable in the room where I would like to connect my modem/router is able to provide television. I didn't change the splitter or cables to get this to work. I simply connected a TV to the cable and was able to see channels. So, if the cable is providing TV, shouldn't it provide internet?

Bronze Problem Solver

Re: Internet through only a specific coax cable?

It should providing the signal levels for the modem are in spec. Only way to find out is give it a try.

Frequent Visitor

Re: Internet through only a specific coax cable?

Jim721,

 

Thanks for the reply. I started with trying the modem/router on that cable first and didn't get internet. I then tried TV and that did work. So, what do you mean "it should providing the signal levels for the modem are in spec?"

 

Thanks!

 

Will

Bronze Problem Solver

Re: Internet through only a specific coax cable?

The Tv uses different frequencys then your internet (modem) uses so you may get the tv to work but that dont mean the signals will be strong enough to work the modem. Tv signals are seperate than the internet signals even though they come through the same line. Cable modems are more senitive to poor signals then a cable tv box as long as the modem sees good downstream and upstream signals and snr's it should work on that line.

Frequent Visitor

Re: Internet through only a specific coax cable?

Jim721: So based on what I've described, would you say that the signal is poor for internet on that cable? If so, how do I fix that? Could it be caused by the splitter?

Bronze Problem Solver

Re: Internet through only a specific coax cable?

Most likely is caused by splitters and maybe just a old coax line poor fittings on the ends.If you have any uneeded splitters try and remove them and try again. Read this thread about connection and what signals modems like to see to work right.

 

http://forums.comcast.com/t5/Basic-Internet-Connectivity-And/Connection-Troubleshooting-Tips/td-p/12...

Contributor

Re: Internet through only a specific coax cable?

OK, here's the deal.  You want only a 2-way splitter behind the modem for max speeds/stable connection.  You very likely have 2 splitters - one that goes between the modem, pole, and 2nd splitter.  Then the 2nd one goes on to the TV's.  I assume you don't have some kind of 'booster' on the TV lines as those are generally 1-way and stop cable modem signals dead, for obvious reasons.  Smiley Wink

 

The modem will tell you how much power it is trying to transmit with (lower=better), and how much it's recieving (probably between -10 to +10).  The modem's manual should tell you what the rough limit is on that model.  If it's borderline already on the first splitter, then splitting it further is likely the source of your problems.

 

It also doesn't hurt to unhook and reconnect (or just tighten) the connectors...  Might just be loose?  Just use the classic process of elimination and an extension cord to check all the lines/splitter outputs.  A laptop taken outside with you can be very handy for when you plug in the modem directly, bypassing the house's wiring.  Not too hard - Good luck!

Frequent Visitor

Re: Internet through only a specific coax cable?

Thanks everyone for your replies. I tried the modem on the cable that led to the splitter. In other words, I unplugged the main cable from the splitter and plugged that into the modem. In that setup the modem was able to provide an internet connection. So, the issue is probably the splitter or the cable after the splitter that leads to the other room or, like jwcc said, the signal isn't strong enough after the second splitter since it doesn't use some kind of booster.

Silver Problem Solver

Re: Internet through only a specific coax cable?

Two possibilities present:

1.  Call Comcast tech support and get a tech out there to clean up the cabling.

2.  Go and buy a cable rated splitter and coax cable and try to fix it yourself.

Please post back with your steps to solution and results.

Diamond Problem Solver

Re: Internet through only a specific coax cable?


jwcc wrote:

The modem will tell you how much power it is trying to transmit with (lower=better),


To a point Smiley Wink Too low is just as bad. 40 to 45 dB is preferable.

Official Employee

Re: Internet through only a specific coax cable?

Two possibilities present:
1. Call Comcast tech support and get a tech out there to clean up the cabling.
2. Go and buy a cable rated splitter and coax cable and try to fix it yourself.
Please post back with your steps to solution and results

If you do number 2, you'll probably end up doing number 1 anyway lol
I am an Official Comcast Employee.
Official Employees are from multiple teams within Comcast: Product, Support, Leadership. We ask that you post publicly so people with similar questions may benefit from the conversation.

Was your question answered? Mark the post as best answer!