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Discussion Starter · #1 ·
I am trying to figure out why my internet services is coming and going intermittently.

I will try to be brief and spare you the horror story dealing with Comcast. I had Comcast cableTV service for a few years, but for internet I was on DSL with another provider. Last week I signed up on the Comcast cable TV Plus internet bundle service for a faster internet and more channels. To do that I have to go get a new modem from them.

Since I already had the TV services and everything was working, it should be a simple matter of splitting an existing cable TV outlet into two - one to TV and one to modem. I did that and once activated I got internet. Except about half the time internet is not there. The modem's ONLINE light blinks.

Called the Comcast tech support and they had me spinning in wheels.

First they said the modem I got was an outdated version, and to go back and change the modem to new "version 3" modem. Local Comcast center said no, that's BS, there is no version 3 modem, they can only give me another one of the same type. I came back with the same modem type, and same problem. TV fine, internet comes and goes.

Called tech support and they said yes there is a version 3 modem. But no worry we will update your firmware. After another 2 hours of updating firmware, waiting, reactivate, reset, power cycle on and off, internet is up. OK thanks. 30 minutes later, off again!

Called them and they said no idea why, but let me send you instructions on how to program your remote control device, and is there anything I can help you with? :madhell:

I asked for supervisor. He said no idea, need tech to come out. There will be a charge! :madhell:

Tech came out, at that moment internet was up. Tech said, well it has to be down for me to diagnose...but he said I need to make sure all my cables are RG6 and connectors are tight. I said OK I guess I can check this.

The coaxial cable goes from underground into the house's attic. I crawled around and found a 1 to 4 splitter in the attic. I think these cables were put in back in 1996 by the last property owner. I also wrote down all the cable's markings. I can't tell if some of the cables are RG6.

INCOMING CABLE - label "E83032 F660BVV CATV" a black cable. From searching on the net this seems to be a kind of RG6?

OUT1: This one is labeled "LL82959 (CSA) CXC 60 C FT-4 COMM/SCOPE NETWORK CABLE RG6/U TYPE E82833 18 AWG TYPE CL2" so I guess this is RG6.

OUT2: This is the same kind of cable as OUT1.

OUT3: Label "E83032 F660BVV CATV" no idea if this is RG6 or not. This is the line that runs to the outlet where I had a 1:2 splitter one to TV one to the cable modem.

Checking all the connectors going to the attic 1:4 splitter I noticed some of them were old crimped connectors gone loose and frayed. So my next move is to redo those connectors with new compression connectors.

First, I have some RG6 connectors but they don't fit the two cables labeled ""LL82959 (CSA) CXC 60 C FT-4 COMM/SCOPE NETWORK CABLE RG6/U TYPE E82833 18 AWG TYPE CL2". I am using a standard coaxial stripper, tried two kinds of RG6 connectors, and both didn't work.



As you can see, the braided shield around the conductor is very thick. Most of the braid I see has a single layer of strands, this one has it in a cross hatch pattern. They are too thick, especially when "folded back", to go inside the compression connector for the center conductor to "bottom". So my question is, is this a special kind of RG6 and is there a special kind of compression
connectors for it?



In my search, some said if the conductor says "18 AWG" it is RG6 is this true?

Finally, does the splitter make a difference? The one in my attic is a 2GHz by "Monster Cable". I saw at local home centers they have splitters for "Digital TV and Satellite". Could the issue be the splitter? May be the one I have now is for analog TV and need to be changed? Or not?

Thanks for any advice or comments.
 

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I can't answer your connection question, but did the Comcast tech check your signal strength. Your internet connection can be poor even if TV and phone are working.

You should be able to see your modem stats by going to http://192.168.100.1/ on any browser. If you can access the page post your signals and look for errors in the log.
 

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Make sure you used a good quality cable preferably with factory install connectors if you don't have the tools and experience to make a good connection . You should split off the internet right where the cable comes into the house and only use a good quality two way splitter . One output goes to your cable modem, the others to the TV. Every time you had a connection or splitter you are reducing signal strength and introducing noise.
 

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1. Do not fold back the braid.

Your coax stripper has two blades. One cuts the jacket AND the braid, the other cuts the dialectric.

2. You cannot, or at least should not, have a splitter after a splitter, due to the insertion loses (3.5db or more per port), which are compounded.

This splitter issue IS almost certainly your problem, as the signal strength would be very low at the cable modem.


The cable company is typically required to provide 7db at the entrance to the structure, so you're looking at having 0db, or less, at the modem.

To rectify this, split outside the home at the entrance, run a direct line to the modem, and direct lines to all the TV locations, and you will not have any additional problems,
 

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Discussion Starter · #5 ·
1. Do not fold back the braid.

Your coax stripper has two blades. One cuts the jacket AND the braid, the other cuts the dialectric.

2. You cannot, or at least should not, have a splitter after a splitter, due to the insertion loses (3.5db or more per port), which are compounded.

This splitter issue IS almost certainly your problem, as the signal strength would be very low at the cable modem.


The cable company is typically required to provide 7db at the entrance to the structure, so you're looking at having 0db, or less, at the modem.

To rectify this, split outside the home at the entrance, run a direct line to the modem, and direct lines to all the TV locations, and you will not have any additional problems,
I see, so you are saying instead of the current configuration where I have a splitter A that splits into LINES A, B and C to three outlets, then at outlet A I further split into A1 and A2 where A1 goes to the modem and A2 goes to a cable box, I should split 4 ways into A, B, C, D where A goes to the cable modem, and B, C, D go to three TVs?

Is there a specific splitter I should use? I picker up an IDEAL 4-way digital HDTV splitter 5MHz-2.4GHz. Says "Low Insertion Loss -9dB per port". I also have an old 4 way splitter a MONSTER CABLE 2GHz also says LOW LOSS OUTPUT 5MHz-1GHz -7.4dB / 1GHz-2GHz: -9.6dB. Both of these seems high if you say -3.5dB is the norm?

Finally, does having inline couplers cause signal losses? I know they might have spliced the incoming line somewhere once or twice with those F-barrel.

Thanks.
 

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miamicuse you should be able to just walk into your local Comcast offices and pick up the splitters.

I had the issue of too high of a signal, when I had Comcast High Speed for six months. They had to use a splitter with a 7dB output to bring it down, because there are hardly anyone in my neighborhood that still has Comcast. So you tend to see higher signal levels.

If you cannot get a RG-6, RG-6Qs fitting on that coax. It could be something else.

96, they would have been using RG-6 at that time.

Comcast has become the worst in Customer Service, especially the crews thaf are supposed to handle customer tickets, but do not feel like crawling in attics and crawl spaces, because they may get dirty.
 

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The 'typical' loss in a 2-port splitter is about 3-3.5 db. In simple terms, that is one half power. If you add another 2-port splitter, that is another 3 db drop, or in simple terms, you now have 1/4 the signal.

Additionally, not all splitters are created equal. You have to look at the specs. In the case of internet over cable, the internet is typically at the upper end of the freq spectrum around 1 Ghz. If you have a cheap or older splitter, chances are it's only good up to about 750 Mhz.

Even if you are only using one splitter, you might have issues. Note, internet is bi-directional, meaning the cable CO needs to see our responses. As noted above, the cable company will frequently crank up the signal to compensate for line loss.....but your cable modem is not cranking up the return signal.

Any time you are using a cable modem and have one or more splitters, the modem needs to be on the first splitter. And if you have a 3-port splitter, look closely at the lable. 2 ports are going to have a 7db loss, and the other a 3.5 db loss. Put the modem on the 3.5db loss port.

I no longer use cable for TV...I'm OTA. Hence, my cable goes directly to the modem. But, for awhile we did have cable TV and internet and I had to install an amp. There was no way I could feed 3 TV's and a cable modem on the one cable. The amp I have has a dedicated port for just the modem and is bi-directional, i.e., it amplifies the signal going back out for the internet stuff.
 

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Discussion Starter · #9 ·
ddawg16, thanks for the advice. You mentioned in an earlier post that I should look at error logs on the modem to see what is going on. This is a ARRIS TG1682G from Comcast and when I connected hardwired and logged on to the modem's the logs are totally useless. It has an event log and a system log. I looked at both logs for the entire week last week. All they have for system logs are the admin log in and log out, and event log showed I changed password once. There is nothing! Unless it is hidden in some low level places only accessible through some debug mode, looked everywhere.

I also looked at the "Connection Status" and this is what it says, although I don't have much idea what most of these numbers mean or if it's even relevant. These are the statuses when the internet is working. I guess when it fails I can find out what the statuses show. The strange thing is when it fails I can't log into the modem even when hard wired. That I don't understand.

 

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Discussion Starter · #11 ·
OK I think I have a slightly better idea.

Over the weekend I went to the attic and removed the three way splitter that splits into output A, B and C. Instead, I put in a F-barrel connector from the incoming line to line A only. Then line A runs to the outlet, and from there I kept the two way splitter, one to cable modem, one to TV. I did this just to see if it makes a difference.

Over the last two days, the internet has been up without interruptions. So removing the two splitters in series does make a difference.

Now the next things is the various different cables I have...I am thinking of running four new RG6 cables to the four outlets A(cable modem), B(TV1), C(TV2), D(TV3). That way the splitting happens in one place and I can experiment with different splitters, amps, etc...in one convenient location.

I went to local home centers and they only have two types of cheap $6 splitters with identical output levels. I guess I need to order online a nicer one?
 

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Discussion Starter · #12 ·
As a side note I know why the "LL82959 (CSA) CXC 60 C FT-4 COMM/SCOPE NETWORK CABLE RG6/U TYPE E82833 18 AWG TYPE CL2" cable won't work with my regular RG6 compression connectors. It is larger in diameter then my "regular" RG6 cable.

I have a coil of the CAROL RG6/U cable. I stripped that cable and the thicker one and laid them side by side. The top cable is the regular RG6. The bottom one is the one I am dealing with. You can see it has TWO layers of copper braids and a larger diameter. This braid is so thick I cannot push it into a regular compression connector no matter what I do.



Since it is labeled RG6/U it must be RG6. Weird. I am planning to change them out to regular RG6, unless someone can tell me what connectors to use and if it's better quality then the regular RG6.
 

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I thought quad shield cables have alum foils. Mine doesn't. If it's QS then my cable is actually better than standard RG6? In that case I should leave it alone?
Some do, some do not. All quad shield is good for, is if you live underneath high voltage transmission lines, or getting noise injected from a local Ham operator or radio station.

Standard RG-6 works fine. Millions of installs have it ran inside the buildings and no issues.
 

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I also looked at the "Connection Status" and this is what it says, although I don't have much idea what most of these numbers mean or if it's even relevant. These are the statuses when the internet is working. I guess when it fails I can find out what the statuses show. The strange thing is when it fails I can't log into the modem even when hard wired. That I don't understand.

The signal levels look good. If you start having issues again, recheck the signals. Downstream power should be between -12 and 12db. Downstream SNR is good at 30+.

Upstream Power, the lower the better. If you get close to 55 you could have a cable or splitter problem.
 
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