Author Topic: coax cable coming into cable modem - ok to split? (Read 6140 times)

screaming · « **on:** March 07, 2006, 04:46:04 pm »

I have the normal coax cable coming into my cable modem at home. I'd like to split that cable and have it also go into my server with a tuner card. Before I go out and spend the $30 on a crimper and potentially eff everything up, does anyone know if that will work?

whammoed · « **Reply #1 on:** March 07, 2006, 04:50:57 pm »

Quote from: screaming on March 07, 2006, 04:46:04 pm

I have the normal coax cable coming into my cable modem at home. I'd like to split that cable and have it also go into my server with a tuner card. Before I go out and spend the $30 on a crimper and potentially eff everything up, does anyone know if that will work?

I have done it before, but the signal for the tuner may be degraded a bit. You are *supposed* to make all your splits at one time, like where the signal enters your house.

ChadTower · « **Reply #2 on:** March 07, 2006, 04:53:44 pm »

He's talking about data, as in network connection, not his cable television.

And the answer is no, get a hub/router inside the modem.

screaming · « **Reply #3 on:** March 07, 2006, 04:57:54 pm »

no, no.

I'm talking about both data and cable television.. I want to put a splitter on the 1 coax cable (not rj45) that goes directly in the back of the cable modem and make it so I have 1 coax cable that goes to the cable modem and 1 coax cable that goes to a tuner card in my PC (i.e. cable TV). I'm not sure if it will work though, as I seem to remember there being some kind of filter on the coax line going to the cable modem that required a special tool (no, not "special tool" like me, a special tool that you'd get at home depot) to get it off.

ChadTower · « **Reply #4 on:** March 07, 2006, 05:00:08 pm »

It's still data. The video signal is digital. You're going to have to split it after the cable modem separates the two.

screaming · « **Reply #5 on:** March 07, 2006, 05:03:02 pm »

I have no coax out on my cable modem, so that won't work.

DrewKaree · « **Reply #6 on:** March 07, 2006, 05:36:06 pm »

I have no idea how your cable works. I have Time Warner and the cable dude who came out here wired this up for me as follows:

Cable comes from the wall jack to a 2-way splitter. One goes to the cable modem, the other went to my tv.

After dude left, I switched the 2-way with a 3-way splitter and hooked the two non-modem lines to my dual-tuner card.

I have no idea if it'll work for yours, but if the cable dude split it with no problems, and I split it further, I can tell you if you're living in WI, you can do it.

Since you live on the east coast, that's just a recommendation.

Why do you need to buy tools? Just get a premade 3' cable and give it a shot.

SOAPboy · « **Reply #7 on:** March 07, 2006, 05:56:17 pm »

You can split it however you want.. Itll degrade after to many splits, but a few wont matter.. your cable modem will pick up the signal it needs, as will your TV and or Cable box..

screaming · « **Reply #8 on:** March 07, 2006, 06:02:45 pm »

Quote from: SOAPboy on March 07, 2006, 05:56:17 pm

You can split it however you want.. Itll degrade after to many splits, but a few wont matter.. your cable modem will pick up the signal it needs, as will your TV and or Cable box..

This was the validation I was looking for

How certain are you that this is the case?

Quote from: DrewKaree on March 07, 2006, 05:36:06 pm

Why do you need to buy tools? Just get a premade 3' cable and give it a shot.

I need to tap into a wire that's already there. My server sits right next to the line going to my cable modem. If I didn't tap into it I'd have to string a redundant cable all through my ceiling.. It's just easier, I guess.

NinjaEpisode · « **Reply #9 on:** March 07, 2006, 08:44:06 pm »

Quote from: screaming on March 07, 2006, 06:02:45 pm

Quote from: SOAPboy on March 07, 2006, 05:56:17 pm
You can split it however you want.. Itll degrade after to many splits, but a few wont matter.. your cable modem will pick up the signal it needs, as will your TV and or Cable box..
This was the validation I was looking for How certain are you that this is the case?

I can validate this. He's right.

HOWEVER, you won't pick up any digital channels on your server, only your basic cable channels. My cable system only goes digital above a specific channel number, like 100 or something like that. My basic cable channels duplicate over to the digital on the higher channels.

BobA · « **Reply #10 on:** March 07, 2006, 11:44:09 pm »

Works just fine. Am using the exact same setup right now to feed TV tuner and cable modem. Couple of things to look out for..... Do not use a $1 splitter. Use a good quality splitter and only go from 1 input to 2 outputs. More outputs = smaller signal. Make sure you coax crimps are clean and solid.

screaming · « **Reply #11 on:** March 08, 2006, 10:25:43 am »

Thanks for the tips! It looks like I'll soon be on my way to streaming TV euphoria. yeah, bitches!

Stingray · « **Reply #12 on:** March 08, 2006, 01:48:50 pm »

Quote from: DrewKaree on March 07, 2006, 05:36:06 pm

Why do you need to buy tools?

I'm going back to Purgatory to neg fu the crap out of you for suggesting that buying tools is not a good idea.

-S

SOAPboy · « **Reply #13 on:** March 08, 2006, 03:30:52 pm »

Quote from: screaming on March 07, 2006, 06:02:45 pm

Quote from: SOAPboy on March 07, 2006, 05:56:17 pm
You can split it however you want.. Itll degrade after to many splits, but a few wont matter.. your cable modem will pick up the signal it needs, as will your TV and or Cable box..

This was the validation I was looking for How certain are you that this is the case?

Quote from: DrewKaree on March 07, 2006, 05:36:06 pm
Why do you need to buy tools? Just get a premade 3' cable and give it a shot.

I need to tap into a wire that's already there. My server sits right next to the line going to my cable modem. If I didn't tap into it I'd have to string a redundant cable all through my ceiling.. It's just easier, I guess.

Well.. my digital cable is split 3 times.. lol..

Scott84 · « **Reply #14 on:** March 08, 2006, 03:33:39 pm »

My cable is split... before the modem... it doesnt affect it.

pointdablame · « **Reply #15 on:** March 08, 2006, 04:05:07 pm »

Quote from: screaming on March 07, 2006, 06:02:45 pm

I need to tap into a wire that's already there. My server sits right next to the line going to my cable modem. If I didn't tap into it I'd have to string a redundant cable all through my ceiling.. It's just easier, I guess.

You're best bet is to put a splitter at the end of the cable, and use/make 2 6" cables to go to where you need to go (or however long is necessary). Tapping into the existing line is not worth it IMHO. Mess it up and you're starting all over. Mess up 6" of coax, and you're out a few cents and a few minutes.

And I'll just echo people here.. it WILL work, no problems. The only foreseeable problem you can have is degradation of quality. My house has too many splits in it, so the cable company had to install an amplifier in my house. You could do that yourself as well if you wanted, but it won't be necessary unless you have a large amount of splitting off the main line. I believe we have 4 or 5 currently.

NinjaEpisode · « **Reply #16 on:** March 08, 2006, 04:18:17 pm »

Quote from: pointdablame on March 08, 2006, 04:05:07 pm

And I'll just echo people here.. it WILL work, no problems. The only foreseeable problem you can have is degradation of quality. My house has too many splits in it, so the cable company had to install an amplifier in my house. You could do that yourself as well if you wanted, but it won't be necessary unless you have a large amount of splitting off the main line. I believe we have 4 or 5 currently.

Two things about the amplifier (1 alleged, 1 it happened to me):

1 - Allegedly, an amplifier installed before a cable modem will cause a problem with the data signal causing the cable modem not to work. I basically installed my amplifier after I split off the modem.

2. - An amplifier can cause interference with a DVR as well. Case in point, we couldn't get On Demand to work on our DVR box in the living room. I removed the amplifier and bingo, DVR is working fine now. Surprisingly, we also got a few extra channels that we didn't have with the amplifier. Go figure.

TOK · « **Reply #17 on:** March 08, 2006, 04:34:17 pm »

You'll probably be fine, but there is no way to say it's cut and dried that it will work or will not.

Most cable modems have an onboard diagnostic. Open your browser and type
192.168.100.1
If your modem has the feature, you'll be able to look and the forward and return signal levels.
Most modems will work with forward data down to -15. Nominal operating window is generally considered -5 to +10 dbmv.

Transmit is how much the modem is pumping out to get back to your provider. Optimal is in the mid 40's. 55 is where things get iffy, and 58 is considered max transmit. If your modem is in the high 50's and the noise floor in the cable plant goes up, chances are its going to drop offline.

A two way will affect your signal both ways by the loss of the 2 way, which is 3.5dbmv.
Modems are happiest no more than 2 splitters deep.

pointdablame · « **Reply #18 on:** March 08, 2006, 09:27:41 pm »

Quote from: NinjaEpisode on March 08, 2006, 04:18:17 pm

Quote from: pointdablame on March 08, 2006, 04:05:07 pm
And I'll just echo people here.. it WILL work, no problems. The only foreseeable problem you can have is degradation of quality. My house has too many splits in it, so the cable company had to install an amplifier in my house. You could do that yourself as well if you wanted, but it won't be necessary unless you have a large amount of splitting off the main line. I believe we have 4 or 5 currently.

Two things about the amplifier (1 alleged, 1 it happened to me):

1 - Allegedly, an amplifier installed before a cable modem will cause a problem with the data signal causing the cable modem not to work. I basically installed my amplifier after I split off the modem.

2. - An amplifier can cause interference with a DVR as well. Case in point, we couldn't get On Demand to work on our DVR box in the living room. I removed the amplifier and bingo, DVR is working fine now. Surprisingly, we also got a few extra channels that we didn't have with the amplifier. Go figure.

My amplifier was put on the main line by a Comcast guy and then sent to my modem and all cable boxes. I have no modem problems at all. I have 3 digital cable boxes in the house that use On Demand all the time, and a ReplayTV in my room in conjunction with the DigiCable box... again with no problems.

And actually, the amplifier was installed specifically for the cable box in my room because it was not getting a strong enough signal. The cable guy took readings through the house and 1 of the digicable boxes was very low and one (mine) was so bad it couldn't get a signal at all. The amp fixed everything up.

delta88 · « **Reply #19 on:** March 08, 2006, 10:46:25 pm »

Meh I read a few other posts but from "the resident Comcast guy" (ME) for installs that allow the cable modem is to be split from the 1st in. I am told we garuntee 4 devices without anamp. which allows for 1 for way splitter without any issues in block sync and "hits" sent to the digi boxes. If an amp is installed then we use a 2 way prior to the cable modem becaus ethe amp will cause a loss in return signal and make it sloow. anything else? DVR secrets? cable box secrets? oh yeah... the Comcast network is so open.. everything they offer can be had .. had...
Amps will only cause issues with cable boxes if the signal is to high which means you never needed the amp in the 1st place and the installer was lazy

Corp 9520 for life

pointdablame · « **Reply #20 on:** March 09, 2006, 09:42:32 am »

everything Comcast has can be... had..... you say

Mr Comcast man..... you should PM me.

I'm sure you're right though... I never noticed a split before the amp, but there probably is one.

DrewKaree · « **Reply #21 on:** March 09, 2006, 09:56:21 am »

Quote from: delta88 on March 08, 2006, 10:46:25 pm

Meh I read a few other posts but from "the resident Comcast guy" (ME) for installs that allow the cable modem is to be split from the 1st in. I am told we garuntee 4 devices without anamp. which allows for 1 for way splitter without any issues in block sync and "hits" sent to the digi boxes. If an amp is installed then we use a 2 way prior to the cable modem becaus ethe amp will cause a loss in return signal and make it sloow. anything else? DVR secrets? cable box secrets? oh yeah... the Comcast network is so open.. everything they offer can be had .. had...
Amps will only cause issues with cable boxes if the signal is to high which means you never needed the amp in the 1st place and the installer was lazy

Corp 9520 for life

Hey PDB, can you disinterpret this for the rest of us?

ChadTower · « **Reply #22 on:** March 09, 2006, 10:21:34 am »

Doh, looks like the dude I talked to when they set me up with cable net access gave me bad info.

pointdablame · « **Reply #23 on:** March 09, 2006, 11:35:15 am »

Quote from: DrewKaree on March 09, 2006, 09:56:21 am

Hey PDB, can you disinterpret this for the rest of us?

For 4 or under connections... you're A-OK by just splitting from the main line coming into the house.

For over 4, you should use an amp, but if one of the connections is a cable modem, you have to split the modem line off the main line BEFORE you connect to the amp. The amp can then connect all the cable boxes in the house.

He also said that Drew was lame... you may not be able to decipher that part of his message... but that's because you are so lame

Hope that helps

Harry Potter · « **Reply #24 on:** March 09, 2006, 12:52:32 pm »

Nice to see you guys can still do that sort of thing.

Here, they attach this big-ass box to the side of your house which splits the signal into digital TV, internet and land phone.

I asked the guy out of interest if I could split say the cable modem line so one would go into modem and one into a receiver/tuner card. He reckons the box on the side of the house filters each coax line so you don't get TV and phone on the data line and so on and so forth.

I guess they wanted to prevent people who get cable internet from stealing Pay TV.

DrewKaree · « **Reply #25 on:** March 10, 2006, 02:03:20 am »

Quote from: pointdablame on March 09, 2006, 11:35:15 am

For 4 or under connections... you're A-OK by just splitting from the main line coming into the house.

For over 4, you should use an amp, but if one of the connections is a cable modem, you have to split the modem line off the main line BEFORE you connect to the amp. The amp can then connect all the cable boxes in the house.

I'm glad you understood, because EVERY post screams "PDB IZ TEH SCUK!" to me. Sure, it's not typed out....ya gotta read between the lines

delta88 · « **Reply #26 on:** March 10, 2006, 02:38:53 am »

As far as that big box goes.. if you have comcast look to see if there are phone looking lines going into it. if so thats just an ISU. sort of an outside mounted VOIP box. We put a pin in at the tap tha tcharges the line to your house with 90VAC. that box turns it into phone data and has an out port that is used for tv and internet connections. those however are old and we now install Arris telepheny modems in your home. And back to the splits, you don't always need an amp with more than 4 splits. its jus tsometimes you start to notice lower levels @ 4 splits. I've seen 8+ without an amp. It all depends. Ask the next tech out to give you the forward and return readings at you tap and at your equipment (if time allows).

ISU= Integrated service unit

TAP= Point of cable access, service point

VOIP=Voice over Internet phone (like vonage, sunrocket)


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