Splitting Cable Internet

[Peter Parker]

Modem signal level Software Version
dpc2100R2-v2.0.2r1256-100324as

Receive Power Level
-4.8 dBmV

Signal to Noise Ratio
36.3 dB

Transmit Power Level
54.0 dBmV

Cable Modem Status
Operational

 

[Peter Parker]

And witha two way splitter in the mancave before the modem

Software Version
dpc2100R2-v2.0.2r1256-100324as

Receive Power Level
-8.0 dBmV

Signal to Noise Ratio
36.6 dB

Transmit Power Level
54.0 dBmV

Cable Modem Status
Operational

Only intermittent net access now

 

[Peter Parker]

The product described in post 16 arrived today. I will try it this weekend.

 

[stardust3]

Post back & let us know how it goes. That is an excellent product, I hope you find the results your looking for.

 

[Peter Parker]

Based on readings I have been taking I think the weak link in the chain is not so much the entry point and the split that takes place there as it is the fact that no matter how I amp it there I get a problem if I try to split it in the room where the modem, tv and dvd recorder are located. For years i split it two ways and there was no issue now that is an issue even with a two way split using the same splitter as before or ones specifically designed for this purpose.


Of course there is always the possibility that this will help just enough to allow a split in the room and/or give me a marginally better analog cable picture (I don't expect to see any difference in the quality or consistency of the digital picture).


Since variosu configurations have worked short term (an hour or so) I don't expect to report back till late Sunday or Monday.

 

[rcbridge]

To the OP from the readings that you gave for the modem when you got it to work, your issue is the return your modem is about maxed at at 54dbmv (yes you are locked) but when you add a larger splitter or an amp that does not amplify the return signal needs to work harder to overcome the additional loss that was introduced and it can't so you lose lock.

 

[Peter Parker]

So why did it work for years and why does it work now most of the time?

BTW that reading is constant ina ll configurations. No change between having it split in the attic and then again in the room, or bypasing all splitters.

 

[rcbridge]

You are pushing your cable modem somewhere near its limit, your upstream reads 54dbmv, in actuallity the modem can do a little more but the reading won't go above 54.
So again everytime you add a device (amp, larger splitter etc) you are asking your modem to work harder, so being near the edge it will work sometimes and sometimes it wont.

If you can get the cable company to come and measure your power level entering your home you can do the math from that point, it is normally suggested to take that entry point and split it 2 ways one for the cable modem and one for all else.
This way any amps or additional splitters installed won't affect the modem.
If this is not possible do your best to keep any amps out of line with the modem unless it has an active return.

 

[Peter Parker]

As I have said before I have called the cable company. Their answer was that thy thought I should not be able to connect at all. I have not seen them come out though a neighbor said that a truck was out while I was not home. If that is true whatever they did made no difference. According to the first level phone rep the problem is more likely connected to my receive level. Having said that most of my research shows numbers ln line with what RCBRIDGE has said. But perhaps my readings (or i suppose theirs are not accurate). I have called back to check on whether they did come out but was basically told they had no record of such a call but i would be called back later. To be honest one reason I have satellite TV is poor customer service so while I am less than satisfied with the response I m not shocked by it. I could tell a number of hrror stories about past service inquiries.

As for the advice on splitting as i indicated the split at the entry point seems to make no difference. The only thing that does seem to matter is split in the room. However not spitting it at all is not really acceptable. While the cable TV is justa backup I am interested in having it.

Right now I am experimenting with different amps and splitters etc in each location. Since the problem is intermittent it is hard to say whether my current configuration which is working is a long term answer or not. When i havea bit more info I will post my results but I suspect that if I posted anything now it would just add to the noise level and all ia m doing right now is troubleshooting through trial and error.

 

[harshness]

A possible cause in the change in behavior may be coming from the channel allocation changing and/or the incorporation of newer technologies that use different frequencies than you're used to. IIRC, DOCSIS 3.0 can use RF frequencies from 5-1005MHz (25-88MHz for uplink, above for downlink).

 

[Peter Parker]

Interesting thought. My system does havea premium tier that requiresa DOCSIS 3.0 modem. I do not have that tier but who knows maybe there isa connection there.

 

[The Insider]

Geronimo first problem I see is you putting an amp on the internet line. First off from what you describe having no boxes, and what seems to be less then 4-5 outlets there is no reason at all for you to need an amplifier in the first place on even the tv lines. If you have an amplifier it means there is a problem somewhere that someone is not fixing. The fact your upstream is so high also indicates that problem.

I would call the cable company again and have them setup a service call. Any tech with half a brain should be able to find the problem and fix it, stop wasting your own money and time. You pay them a lot of money to provide you this service and if its not working properly they need to fix it.

To those talking about splitters, there would be no noticeable difference for him using a 1ghz splitter vs a 3ghz splitter. As his cable system is likely not to be higher then 870 anyway, as very few systems in the nation are 1ghz. And as far as amplifiers go, there is hardly any reason to have them in your home unless you have several outlets (were talking 6/7+) or if you live very far from the tap and have a drop exceeding 250'. If you have a house amp it means someone put a band aid on a problem.

 

[goaliebob99]

FYI You need a Digital Directional Couplers like this that passes power. Antronix - In comes from the cable line, out goes to the tv's then to a splitter. Tap goes to the cable modem. They are specifically made to pass cable modem signals from the tap port.

 

[grohgreg]

To those talking about splitters, there would be no noticeable difference for him using a 1ghz splitter vs a 3ghz splitter. As his cable system is likely not to be higher then 870 anyway, as very few systems in the nation are 1ghz. .

Well, I still disagree. Cable delivery systems are getting more frequency intensive, not less. See http://www.belden.com/pdfs/PDF/hdcarltp.pdf

But more important I think is why there are any non-native splitters/amps in the first place. Are the existing splitters/amps part of the original cable company installation? or were they added by the customer at some later date?

DOCSIS was mentioned, as was television and internet. I'd considered that bundled service. With or without phone service in the bundle, shouldn't the DOCSIS modem do the actual "splitting"?

//greg//

 

[rcbridge]

DOCSIS was mentioned, as was television and internet. I'd considered that bundled service. With or without phone service in the bundle, shouldn't the DOCSIS modem do the actual "splitting"?

NO.

Well, I still disagree. Cable delivery systems are getting more frequency intensive, not less.

At this time most cable systems are below 1Ghz and typically to out at about 870mhz.
To go above that 1Ghz frequency it will take a fairly significant modification to the entire cable plant from the head end to your home, most passive devices in line at this time are only rated to 1Ghz.

 

[grohgreg]

Ok, I'm clearly in the minority here - but that could be cuz I'm primarily a satellite guy. What I'm reading from the cable guys is, "build for today - let tomorrow take care of itself". I'm more inclined to overbuild up front, thus minimizing time and expense of retrofitting as technological advances present themselves. So I guess I'll just let you status quo guys run with this.

//greg//

 

[rcbridge]

Ok, I'm clearly in the minority here - but that could be cuz I'm primarily a satellite guy. What I'm reading from the cable guys is, "build for today - let tomorrow take care of itself". I'm more inclined to overbuild up front, thus minimizing time and expense of retrofitting as technological advances present themselves. So I guess I'll just let you status quo guys run with this.

This is just the reality of how it is built as we discuss it.
To help the OP we need to relate things to the present.
Going forward I can agree with you on some things but that is yet to be.
What the future will bring we will have to wait and see.

 

[Peter Parker]

OK Here is Wher I am

I definitely need an amplifier in the attic. However there is no noticeable difference whether I use the in in post 16 or the one i mentioned using earlier as long as the correct port is used for output to the room involved.

I did experiment with another amplifier in the room but it had no positive effect. Interestingly the issue with splitting the cable modem in the room was "solved" for now by using an ancient 3 way splitter I had. It has no makings indicating that it is two way etc but it is working for now and has been for about the last 18 hours. this surprises me because a DCC from Crutchfield led to occasional problems as did every other splitter I used in the room regardless of how they were rated..

Obviously I will continue to monitor this. I really am surprised that this splitter is working so i expect some incredulity from this crowd.


Ironically this may be less important than I thought. I am a satellite sub and was frustrated with OTA reception of one channel that has improved dramatically. That coupled with the fact that Cox has moved several local channels means I may be using OTA as my backup for the TV---although it is nice to have cable on the DVD recorder for the few channels that Cox allows me that satellite does not.

to those who want me to arrange for a service call, As I have explained I have been on the phone with Cox several times. It has been a comedy of errors as have most service experience with them over the years. The customer service there is the main reason i switched to satellite for TV years ago. If it fails completely obviously I will call them (or Verizon for DSL or FIOS) but I really don't se the point in dealing with them any further than i already have.


i know people have better things to worry about than this but i will report back if anything changes and i appreciate the advice.

 

[Peter Parker]

Things till seem fine several days later. I thank everyone that offered advice. it was all valuable in trouble shooting and I am enjoying my renewed access to cable TV in that particular room------which happens to be the best place to put my wireless router. I disd not want to have to choose between cable and internet there and now i don't have to.

 

[The Insider]

Ok, I'm clearly in the minority here - but that could be cuz I'm primarily a satellite guy. What I'm reading from the cable guys is, "build for today - let tomorrow take care of itself". I'm more inclined to overbuild up front, thus minimizing time and expense of retrofitting as technological advances present themselves. So I guess I'll just let you status quo guys run with this.

//greg//

The problem is the higher the freq. the greater the loss. Its hard enough right now for the cable company to maintain a plant at 870 (and in rare cases at 1ghz) and keep a high quality of service. The cable company really has no need to go beyond 1ghz Its much more cost effective and valuable to the company to simply reclaim the analog channel bandwidth. Which is why you see cable companies more and more going all digital or removing channels from the analog line up.

Reclaiming the analog lineup alone would add as bandwidth as upgrading the entire plant to 2 ghz. (which would be a HUGE expense, and be impractical with current design and and cause the plant to be redesigned)