Cable modem coax cable issues through splitter.

[SuperTool]

Modem works fine when directly connected to the jack, but not through a splitter, even when nothing is hooked up to the second outlet.
The splitter is Regal DS2DGH10 5-1000MHz 120dB EMI Isolation 2 way splitter.
Outputs say 3.5db. I tried it with a cheapo splitter from fry's too, same problem. And it's not the cables because hooking up directly works with both.
Any one familiar with why I would be having this problem?

 

[Bleep]

Right off the bat I would guess that the signal strength is just marginal and the couple of DB that you lose with the splitter is just enough to drop the connection. You lose the signal stregnth through the splitter even though there is nothing else connected to the splitter.

Bleep

 

[gunrunnerjohn]

I'd call your ISP and complain, since you need to be able to split it at least once to get your TV and cable service from the same line. If you're that close to the edge, you'll have constant dropouts whenever the phase of the moon changes.

 

[MikeDub83]

I have heard that splitters that amplify cable signals will cause problems with cable modems.

 

[masul0100]

Originally posted by: MikeDub83
I have heard that splitters that amplify cable signals will cause problems with cable modems.

False, I have a 4-way amplified splitter and it works great (unless the splitter get's umplugged and then TV and modem both crap out). I think I paid about 40 at Radio Shack, worth it for me.

Masul

 

[gunrunnerjohn]

There are a few two way amplified splitters, but IMO it's pointless. If the ISP isn't delivering enough signal for the cable modem to function properly without amplification, you need to get on their case to fix that issue, not add amplifiers. Remember, faint noise becomes strong noise after going through an amplifier, there is no substitute for proper signal strength from the ISP.

 

[SuperTool]

What I don't understand is if I only connect one side of the splitter, it still doesn't work. So it's not the load of the TV, it's the splitter that's causing problems.

 

[gunrunnerjohn]

Actually, connecting only one leg of a splitter is bad, you get reflections from the open port. You need a terminator on the open leg to properly evaluate if the splitter is doing the damage. If you've tried multiple splitters, and they have 5mhz - 1000mhz bandpass, you don't have enough signal strength, time to fix that problem first.

 

[Wolfie]

I remember when I had cable installed on this machine. They took all "MY" splitters and replaced them with ones they said I should use.
They are 2way spliter GHS-2 5-1000mhz -3.5db out on both. I have three of these splitters before coming to my modem. I download 3mb and never had a problem the last four years.
Also, when they installed the cable, they added a filter to the TV side of the spliter. According to the installer, this was to filter out the internet stuff from our tv's to reduce TV picture noise. They have to have a special tag on the pole so they DO NOT add a filter to my service. They add filters at the pole for people that do NOT have internet service.
You might want to call your ISP to get them to come out and take a look at why your not getting your service.

Bad pics using a cheap web cam...

Splitter
Filter

Hope this all helps...

Wolfie

 

[TJN23]

From my understanding and experience with the cable guys, any unnecessary splitters in your coax setup is bad, as the signal will unnecessarily attenuate.

 

[ScottMac]

The signal is split, whether you have a connection on the post or not. On a two-way splitter, you will lose more than half the signal automatically (the split, plus the "insertion loss").

You mentioned "-3.5db" per leg --- 3db = half (or twice, depending on the operation). A three-way splitter can be up to -7.5, sometimes more ... that less than 25% of the original signal strength (almost down to ~1/8th).

Every connector, every kink, twist, brusie will take it down even more.

Chances are you have either a flakey connection (oxidized or poorly terminated) or a poor signal strength to begin with. If you call the cable folks, they will send a person with a field strength meter who should be able to adjust the signal strength to the desired level, splitters and all.

As a last ditch, I'd say to disconnect and reconnect every device between where the cable come into your house and your computer. While it's disconnected, look at it to see if it looks dull and / or corroded. If it is, replace it. You should be putting in something that will pass up to 900-1000 Mhz with the losest loss you can find ... which will be 3.(something) on a two-way split.

DO NOT use a three-way (or more) splitter if you only use two ... the signal is dropped to each connector whether you use 'em or not.

Another way to go is to put a two-way at the entrance; one leg directly to the cable modem, the other to the TVs, split any way you need it (with amps, if necessary at the original split).

Good Luck

Scott

 

[gunrunnerjohn]

My standard installation is a 5-1000mhz splitter right at the cable entrance, a home run to the cable modem with low loss cable, such as RG-6U, and no splices if it can be helped. It doesn't get any better than that.

 

[SuperTool]

Thanks for your replies. It's all of the sudden working with a splitter now. Not sure why. There have been some outages last week, and then it stopped working with a splitter. Now it's working again
Basically I asked here because I much rather preffer to resolve this without inviting the cable guy and sitting here skipping work to wait for him.

 

[VTEC01EX]

Ask the cable guy for a DC Tap... Like a splitter, only one leg has a significantly lower signal loss than the other. Obviously, the other leg suffers, but having reliable cable modem service was more important than having good looking TV in my case. My TV still looks like crap though... I hate WideOpenWest.

 

[tallman45]

When you say Coax are you referring to RG-59 ? If so then you are using the wrong cable. Cable TV and Cable internet should be using RG-6 cable.

http://www.smarthome.com/8527.html

 

[gunrunnerjohn]

If you have to resort to such things as a DC-tap, you have a very marginal signal anyway. You should have at least 10-12 dB of headroom in the signal, or a small breeze on the wires will be enough to knock you off the air!