Cable modem won't work off a splitter... any solution? ::NOW WITH PIX::

VTEC01EX

Senior member
Mar 8, 2002
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The setup:

On the 2nd floor of my house I have two TV's and my cable modem. I previously had Time Warner cable, and everything worked perfectly (line in -> splitter -> all devices). Now I've concerned to WideOpenWest, and I can't get everything working with the splitter. If I plug the cable modem directly into the wall, it works great, if I hook up the splitter with the TVs on it, they work great. But the second I try and connect the modem to the splitter - even with no other devices connected and even on my amplified splitter - the modem won't work. Has anyone else seen this? Am I just going to have to deal with no TV upstairs?
 

Amorphus

Diamond Member
Mar 31, 2003
5,561
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signal's getting to weak, I bet. get an amplifier from bestbuy or radioshack or something.
 

43st

Diamond Member
Nov 7, 2001
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Have a tech come out, measure the signal, and replace the splitters with the proper tap value. Do not put an "amplifier" in line.
 

CanOWorms

Lifer
Jul 3, 2001
12,404
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I just had the same problem with RCN. They replaced the splitter in the wall with a 3-way splitter and put the cable modem on the stronger split.
 

TechnoKid

Diamond Member
Feb 12, 2001
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If the signal is weak, and you wanted to use an amp, you put the amp on at the ground block, not at the wall outlet; if you amp at the wall outlet, you are also amping all the signal interference etc.

You prob have a bad splitter, either that or a cheap one. Try and get a signal vision or channel vision splitter, or a monster cable splitter.

Cable FAQ Read up on that. It has all the info you'll need. A very good FAQ imo.
 

VTEC01EX

Senior member
Mar 8, 2002
315
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The wiring outside looks shady, too. I'm in a townhouse, in a row with maybe 5 units. The box is at the other end of the row. Upon looking at the wiring outside, it looks like there's already a splitter, possibly two out there. It looks like there's a line that runs the length of the row to my unit, then a splitter, then the line that runs downstairs and the line that runs up. There's also 20 million other wires from Time Warner and some other cable company.
 

TechnoKid

Diamond Member
Feb 12, 2001
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Originally posted by: VTEC01EX
To all of those that suggested boosters/amps.. this is what I currently have:

http://www.radioshack.com/product.asp?catalog%5Fname=CTLG&product%5Fid=15-1197

Cable runs straight from the wall into the input, then cable modem and two TV's plug into 3 of the 4 outputs. Adjusting the gain didn't help. I also tried a few traditional 1100mhz splitters I had sitting around, and a crappy looking 900mhz one, no dice.

Here's what you do. Run a two way splitter from the wall outlet. Then plug your cable modem into one of the ports on the two-way splitter. Plug the other port into another splitter (or into the amp and then into another splitter) to run that to your tv. Doing it this way will have the least insertion loss and will provide the best signal your cable modem can get after a split. (2way splitters only have like a .5db insertion loss and 2-3db leg loss)

If you plug you cable modem into a four way splitter, it wont work well because a 4way has a lot of signal loss per leg (about 7.4db on good splitters).
 

amdskip

Lifer
Jan 6, 2001
22,530
13
81
Originally posted by: VTEC01EX
The wiring outside looks shady, too. I'm in a townhouse, in a row with maybe 5 units. The box is at the other end of the row. Upon looking at the wiring outside, it looks like there's already a splitter, possibly two out there. It looks like there's a line that runs the length of the row to my unit, then a splitter, then the line that runs downstairs and the line that runs up. There's also 20 million other wires from Time Warner and some other cable company.
pics:)

 

TechnoKid

Diamond Member
Feb 12, 2001
5,575
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Originally posted by: VTEC01EX
The wiring outside looks shady, too. I'm in a townhouse, in a row with maybe 5 units. The box is at the other end of the row. Upon looking at the wiring outside, it looks like there's already a splitter, possibly two out there. It looks like there's a line that runs the length of the row to my unit, then a splitter, then the line that runs downstairs and the line that runs up. There's also 20 million other wires from Time Warner and some other cable company.

You need to get a new drop line to your complex, a new drop meaning no splits between your wall outlet and the cable co headend block tap. To many outside splits before your wall outlet are causing the bad signal to your wall outlet.
 

VTEC01EX

Senior member
Mar 8, 2002
315
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Alright, pics are forthcoming... I'm headed outside right now.

I did try just using a two-way splitter, hooking the modem up to one leg, and the amp'd splitter thing off the other... no go. I'll get some pics of the whole setup and brb.
 

VTEC01EX

Senior member
Mar 8, 2002
315
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Thanks to the DSL reports cable modem FAQ, I have some numbers from my modem...

This is when connected without any splitters (which is why I'm able to post this):

Receive Power Level
2.78 dBmV
Transmit Power Level
51.25 dBmV


Downstream Status
Operational
Channel ID
3
Downstream Frequency
621000000 Hz
Modulation
QAM256
Bit Rate
4351590 bps
Power Level
2.76 dBmV
Signal to Noise Ratio
36 dB


Upstream Status
Operational
Channel ID
1
Upstream Frequency
31500000 Hz
Bit Rate
563200 bps
Power Level
51.25 dBmV
 

VTEC01EX

Senior member
Mar 8, 2002
315
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Interesting - after swapping cables out left and right, it looks like I've finally gotten it. However, it looks like I've BARELY gotten it, as my upstream power is just about at the max level. I guess if it craps out and I can't get it going, I'll just have WOW come out and run a more direct line to the box, then try and get a really nice two-way splitter.
 

teckmaster

Golden Member
Feb 1, 2000
1,256
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as a couple of people said before, you need to use a splitter that goes from 5 - 1000+MHz. RadioShack has one and its like $17.99. Amplifiers don't bring the signal up right and they will not work.
 

Squisher

Lifer
Aug 17, 2000
21,204
66
91
How many way splitter is this.

If it's more than a two way, I would put a quality two way in then another splitter off of one of the branches for the TVs.

This what I did one two way and one eight way.

I hate video amps. I've probably spent $300 on amps over the years and they all eventually introduced some noise into the video stream.

 

VTEC01EX

Senior member
Mar 8, 2002
315
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I've actually already got a good 2-way splitter. I believe it's a Regal, which is what the FAQ at DSLreports recommends. I got it from the cable company. I also have what I believe is a version of that RadioShack splitter - it was expensive as hell when I bought it, and it works great on the video, just not with the modem. They are both 1Ghz splitters. I'm happy now, it works, I dont know how, but it does... I'm almost thinking maybe the coaxial cable running from modem to splitter was faulty or just not good enough, because that's what finally resulted in it working.
 

element

Diamond Member
Oct 9, 1999
4,635
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If all else fails, or if you want to improve the signal to noise ratio just a tad more, try running a thick ground cable directly to the splitter itself.

I did that and it made all the difference in my setup.
 

VTEC01EX

Senior member
Mar 8, 2002
315
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Thick ground cable, eh? Anything in particular I should look for when considering cables? Just the thickest possible one? I actually fixed the modem problem by putting the tickets cable from it to the splitter, so I do think this is part of the problem.
 

TechnoKid

Diamond Member
Feb 12, 2001
5,575
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Originally posted by: VTEC01EX

Pic of first floor external wiring

First floor, zoomed out a bit


Keep in mind some of this is Time Warner wiring too...


In this pic (kind hard to tell), it looks as if the cable on the far right is RG59, which is inferior to the much thicker RG6QS next to it. This RG59 cable, if followed up in the upper pics comes from the cable company.

The RG59 cable that is coming from the cable company is going into a tap, which is bad. That could be your problem right there if you are on this line. Taps have severe signal loss on one leg, and also have bad insertion loss compared to a 2 way splitter. The combination of the tap and the RG59 is what is causing a bad signal to your wall outlet.

The connectors on the cable are also bad quality, they are of the older "crimp" style and are not as good as today's SNS (snap n seal from thomas and betts, industry standard by todays' cable companies), I'm sure that these crimped connectors are allowing ingress and moisture into the connection. It looks as though the thicker RG6QS cable on the 2 way splitter is using SNS connectors.

I would contact your cable co and ask them to rerun the wire from the block distribution amp using RG6 quad shield, and also replace that tap with a good 2 way splitter. If they are unwilling to do this, at least replace the tap with a 2 way splitter yourself, if this is your line. Once they measure how bad the signal is, they'll prob rerun the drop line.

Also see if they would run a dedicated unfiltered/split drop line for the cable modem. The reason to have a dedicated drop line for the cable modem is to minimize insertion loss, which occurs and increases depedning on how many plits you have. The FAQ explains it better. The more insertion loss, the more upstream power your cable modem has to use.

Your cable modem's downstream levels look ok, but the tap and the RG59 cable is probably what is causing your upstream power to be at 50+db. Remember, the more insertion loss you have, the more power your cable modem has to use to transmit back to the cable company's head end.

As for the interior cable, you should be using RG6 cable for the patches. RG59 is not cable modem friendly. You can use RG59 for video, but RG6 is much, much better than RG59 cable.