Problems with cable modem and splitter.

By pimpshiznid
in Smart Home, Network & Security

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Grand Master

pimpshiznid

Posted
Posted

Here's my problem: I am running a SurfBoard SB5100, and the cable connection runs from the pole, across my small back yard, and it comes to a splitter, that will run cable to my room upstairs, and to the downstairs for tv. When it enters my room, it goes directly to the cable modem. So, now that I have a TV card, I want to split the connection from my cable modem to the back of the comp to the TV card. I had a 900mhz splitter, so I connected it, ran the cables, and I had TV and internet... for a few hours... Then I couldn't connect on the internet.

So, I read around the internet, and found that a 1ghz or higher splitter was needed to prevent downgrading the connection. Aha, I say, and I run down to RadioShack, buy a RCA 2Ghz splitter and a little bitty connector so I have the smallest length of cable between the splitter and the cable modem. It works! But again, only for a few hours.

What could my problem be?

I was wondering if maybe the length of cable on the other end may have something to do with it. I have a 25 ft cable running between the cable modem and the comp, which is actually only about 3 feet apart. But I figured since the TV connection runs at a lower bandwidth that the internet, I'd be fine there. And really, there should be any degrading in the splitter and connector.

Grand Master

pimpshiznid

Posted
  • Author
Posted
ok i had a similar problem cable wored fine till i messed with the cable wire goin into the modem and would get constant dc's and found that there was a bad connection at a splice in the basement that solved my problem

Ok, I should check that... LMAO, I don't think I have a ladder that tall...

Funny, I just reconnected the splitter, and I can't see the diagnostics page anymore.

Experienced

El_Cu_Guy

Posted
Posted (edited)
you need at least a 1 ghz splitter

Obviously you weren't paying attention:

Aha, I say, and I run down to RadioShack, buy a RCA 2Ghz splitter and a little bitty connector so I have the smallest length of cable between the splitter and the cable modem.

If you remove the splitter and just run the connection directly to your cable modem does it work? If not you need to read on. If you really wanna narrow down the problem the read on.

OK, don't buy stuff from Radio Shack. The first thing that you need to do is get a splitter rated at 5-2300MHz or higher. When I worked for Dish Network (directly not a retailer or subcontractor) we used high frequency everything (splitters, groundblocks, etc). Make sure that the cable running to your modem uses the power pass port (some splitter have one, I used one I jacked from DNS in which all port are power pass :D )

So what could your problem be? Well It sounds like you replaced the splitter that sits behind your cable modem and TV card, but not the one that the cable company installed. That could be your problem right there. Yes even brand new equipment the cable guy installed could have gone bad.

The other problem could be you wiring. Is the cable running in the room where you're having problems RG6 or did they use RG59? The small cable you picked up from Radio Shack, what type is it? It needs to be RG6. High frequecy signals will burn out RG 59. When it enter the room has it been bent rolled (possibly too tight) or eitherwise damaged? RG6 is a hell of a lot more sensitive than RG59. Be careful if you roll it too make the loop large enough to prevent this (your palm to your elbow).

Check what the cable guy did. It should run from a pole to either a high frequency ground block or a high frequecy splitter. Either way it should be grounded. Make sure they used weather boots between the F connectors and the splitter/ground block. Rain could have damaged the connections.

After you have inspected everything call your cable provider. Let them know what your problem is and something that you have noticed that may be causing problems. If they say they will send a tech, make sure to ask that they use high frequency F connectors (Comcast is better at this than TW), ground blocks, splitters, a RG6 cables. If they need to run new cable over existing and possibly drill new holes (or enlarge existing ones because RG6 is fatter than 59that's ok). This is called overbuilding. It may mean waiting a little longer for the tech to come out but it will be worth it.

How do you tell if it's high frequency or not?

1.jpg

Notice the red in the center of the F-port? High frequency is usually red, dark blue (almost looks purple), and yellow. There are some companies that do use other colors but you should ask the installer what it's rated at (ask to see the bag they came in if he's got it). Low frequency is usually clear or even light blue. Take note that many cable modems have clear barrel connectors on the back. This may just be some oddity or it may be stupidity.

Edited by El_Cu_Guy
Grand Master

pimpshiznid

Posted
  • Author
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If you remove the splitter and just run the connection directly to your cable modem does it work?
Yes. Always has. Adding the splitter messes up the line after a few hours. Though, when I run line quality tests, and speed tests, I get no problems, and the speed is the usual.
The other problem could be you wiring. Is the cable running in the room where you're having problems RG6 or did they use RG59? The small cable you picked up from Radio Shack, what type is it? It needs to be RG6. High frequecy signals will burn out RG 59. When it enter the room has it been bent rolled (possibly too tight) or eitherwise damaged? RG6 is a hell of a lot more sensitive than RG59.

Good question, I can't tell, since there are no markings on the cable. The small cable is actually just a little metal connector. I wasn't rolled, and it isn't damaged.

Check what the cable guy did. It should run from a pole to either a high frequency ground block or a high frequecy splitter. Either way it should be grounded. Make sure they used weather boots between the F connectors and the splitter/ground block. Rain could have damaged the connections.

I would check that, but I honestly don't know how I am going to get up that high. It is about 20-30 ft up. Also, it's dark out and midnight, so I can't do it anyway.
After you have inspected everything call your cable provider. Let them know what your problem is and something that you have noticed that may be causing problems. If they say they will send a tech, make sure to ask that they use high frequency F connectors (Comcast is better at this than TW), ground blocks, splitters, a RG6 cables. If they need to run new cable over existing and possibly drill new holes (or enlarge existing ones because RG6 is fatter than 59that's ok). This is called overbuilding. It may mean waiting a little longer for the tech to come out but it will be worth it.

Eh. If I have to call the cable provider, I think I have to pay. I know that I had pre-ran wiring, and I got stuck with a $25 installation charge. My cable provider is a little rinky-dink hometown one.

Yeah, I just had to disconnect the splitter again, because I lost internet. Took less than an hour this time.

Collaborator

fuelman

Posted
Posted

You might want to consider a signal booster

Here's a review of the booster that seems to sum up your problem:

Since moving to a rural area, my cable modem reception became very unreliable. The modem would lose synchronization with the ISP's network several times per day. I had techs from the cable company examine my set up two times. They could not find anything wrong. The only recommendation they could give was that I not use a signal splitter. I had one cable going to my modem and the other to my ATI All-in-Wonder video card. Removing the splitter improved my modem reception a little, but the synchronization problems persisted, and I could no longer watch TV on my computer.

By chance I saw this signal amplifier in the store. My experience with such consumer electronic gizmos has not been good so my initial reaction was to shy away from it. But since it was from Motorola, the manufacturer of my cable modem, and the clerk would take it back if it didn't work, I decided to give it a try. I am very glad I did!

Using this signal amplifier has solved all of my cable modem synchronization problems. Network synchronization now happens within ten seconds of powering-up my modem, where before it would take two minutes, if at all. Furthermore, my modem stays connected-it hasn't gone down since I installed the amplifier.

Link to booster and review

I'm sure you could find one for cheaper than that if you looked hard enough.

Experienced

El_Cu_Guy

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Posted

Could you post an image or link to the connector that you bought from RadioShack? If possible make sure that the F port your cable modem line is connected is power pass. It may be a short somewhere. My guess is that it may be your splitter or this connector you used. I'd also like to know exactly which splitter you bought if you can link to that.

I don't think that purchasing an amp at this time is necessary until we examin the problem fully. Then again it's 3:30am and I can't friggin sleep!

Experienced

Qumahlin

Posted
Posted

Your missing a key part of info we need. Your signal levels.

Goto http://192.168.100.1 when the modem is connected and goto the signal page. Cut and paste up what your downstream, upstream and SNR is.

Also goto the log page right after the modem has reset and post your logs so that we can see what the documented reason for the reset was.

Grand Master

pimpshiznid

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Your missing a key part of info we need. Your signal levels.

Goto http://192.168.100.1 when the modem is connected and goto the signal page. Cut and paste up what your downstream, upstream and SNR is.

Also goto the log page right after the modem has reset and post your logs so that we can see what the documented reason for the reset was.

I can't access the page with the splitter in.

Without the splitter in, my numbers are

Downstream:40

Upstream:50

SNR: 7

Also, when I goto the log page, it says my last reset was in 1970... :huh:

Grand Master

Steven

Posted
Posted
I can't access the page with the splitter in.

Without the splitter in, my numbers are

Downstream:40

Upstream:50

SNR: 7

Also, when I goto the log page, it says my last reset was in 1970...  :huh:

Downstream power Range should be: [DOCSIS limits -15..+15 dbmV]

Carrier to noise Range should be: [Normal in 30..38 dB range]

Upstream power should be [Normal range 30..55 dbmV]

Your upstream power is fine. Your downstream and CtoN Range are way off..

Contact your cable company for a service call to check the levels and/or modify your home for a proper install.

Grand Master

pimpshiznid

Posted
  • Author
Posted
Downstream power Range should be: [DOCSIS limits -15..+15 dbmV]

Carrier to noise Range should be: [Normal in 30..38 dB range]

Upstream power should be [Normal range 30..55 dbmV]

Your upstream power is fine. Your downstream and CtoN Range are way off..

Contact your cable company for a service call to check the levels and/or modify your home for a proper install.

I may have got downstream and snr mixed up...

Downstream:7

Upstream:50

SNR: 40

Does that look any better? I can't check as the splitter is inline right now, and I am performing a test to see if I switch the port on the splitter, if it stays up. So far, up for an hour.

Grand Master

pimpshiznid

Posted
  • Author
Posted
The other problem could be you wiring. Is the cable running in the room where you're having problems RG6 or did they use RG59? The small cable you picked up from Radio Shack, what type is it? It needs to be RG6. High frequecy signals will burn out RG 59. When it enter the room has it been bent rolled (possibly too tight) or eitherwise damaged? RG6 is a hell of a lot more sensitive than RG59. Be careful if you roll it too make the loop large enough to prevent this (your palm to your elbow).

Oh, yeah, I check my wires, at least, the ones I could reach, and found I have RG6.

Enthusiast

Captain Caveman

Posted
Posted

Yeah, they may all be RG6.. but that connector you showed I doubt is (I've never heard of a tiny RG6 connector.. lol).

To the Splitter and FROM the splitter to the cable modem HAS to be RG6.

Ditch that little connector and replace it with a small RG6 cable and see what happens..

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