US Cable Support > RCN > [Speed] Speed isn't what I pay for in Wind Gap

[Speed] Speed isn't what I pay for in Wind Gap

I use a signal splitter that RCN supplies specifically for cable modems (labelled "PDI-DCWS-6"). That is connected to my incoming cable on the "IN" port and splits off the cable modem on one port (the 6-dB tap), and then supplies the TV signals on the "OUT" port. That way, the cable modem receives the maximum signal possible. Ask them about it.

But then, to boost up the TV signals for distribution around the house, I use a good-quality (don't bother with a bad one) TV drop amplifier. Mine is made by Scientific Atlanta, but I don't see those available by that name any more, but this one seems to be pretty much the same thing.
»www.amazon.com/DIGITAL-AMPLIFIER···mplifier

Also, I have had a problem with ground loops putting an AC voltage on the incoming cable; it was large enough to cause a spark when connecting the ground side of the cable. And it shortened the life of the coaxial cable connector right outside the house; the contacts corroded, and RCN had to replace them every couple of years. Whether you have that problem probably depends on how the power lines are routed into your house. But if so, you can get rid of it with an RF isolator. You connect it first to the incoming cable, just before it goes to the RCN cable modem splitter, and it keeps all the AC voltages out of the house cable distribution system.
»www.markertek.com/Video-Equipmen···FF.xhtml

My signals are fine now both for the cable modem and the TVs.

My problem is I don't know much about how cable splitting works/affects things. I know the more times you split it the weaker the signal is, but that's about the extent.

It comes into the house via our basement and is immediately split with a splitter from RCN. Not sure if it's the one you mentioned but I'll check it out. It splits probably 2-3 more times from the basement. I have a TV down there, a TV upstairs in the living room, a TV in the kitchen, and one in my bedroom. The modem is also in my bedroom. There's a spare bedroom that has a cable jack but nothing hooked to it so I'm assuming it is split to there as well.

I'm sure the layout is rather inefficient but I just don't know how to re-do it.

I may look at the amplifier too. If I can check the cable going into the house for corrosion I'll do that too. Something tells me they did come by a few years ago to replace a cable out there.
--
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reply to ice

The 4 dB connector will give you the best signal for the cable modem. The 8 dB connectors apparently are from splitting the signal from a 4 dB node into two paths, so they each get half as much signal.

The term "dB", refers to decibels, which is one-tenth of a bel (named after Alexander Graham Bell). They measure power ratios. So if you split a signal into two paths, they each get half as much power. A bel is a logarithmic measure, and the log of 1/2 = -0.3. Therefore, you get a reduction of 0.3 bels, or 3 decibels. There is some additional loss in the circuit, so in effect you take a 4 dB loss on the one port, and 8 dB on the others since they are further split as described above.

That's what I thought at first, I wonder why there was no change in the signal at all though, I thought it would make some sort of change.

Given the setup here, and the fact that putting the internet on the "best signal" route doesn't help my levels, I'm wondering if there's anything I can do at all.

Yes, that will do it. You can't get any better signal to the cable modem than that. If it is not enough, have them send out a tech to measure the levels. It is a free service call (at least it always has been for me).

Thanks, I'll do it before I go to bed tonight.

Have you called RCN about this problem?

Is this low signal issue you are having something that RCN should/would need to fix? It almost seems that they are not giving you a strong enough signal from the curb to support any splitter on the modem drop. Replacing lines inside your house would not fix this type of problem.
--
The difference between genius and stupidity is that genius has its limits.

reply to ice
I am not familiar with the cable phones, but it looks like your signals are right on the edge of useability, and any additional loss pushes them over the edge. The cable loss depends on the length and the size (diameter) of the cable, but is typically around 6 to 10 dB of loss per hundred feet; maybe more at the higher frequencies.

How long is the cable to your cable modem? That should not matter too much, since the cable modem frequencies are lower than the TV frequencies as I recall, and so the loss will be less. I wonder if that cable could be bad though, and perhaps should be replaced. Otherwise, I agree with pende_tim that RCN should be doing a better job of giving you a good signal to begin with.

I haven't called yet, no. Is this something they'll only need the outside of the house with? I'm not going to be able to take off from work for their usual 4-6 hour window they give when showing up. If they can check/test from outside that would be nice.

I have no idea about the cable to my modem that's inside the wall. The one from the modem to the wall is only 3-4ft, but from the basement up to the room the modem is in is probably 30-40ft. I have no idea what it does once it goes up the walls though.
--
Intel X3350 Quad@3.6GHZ
Abit IP35 Pro
4096MB of Gskill
320GB+500GB SATA
nVidia 8800GTS 512MB OC

If you could run a temporary cable from the RCN cable to your cable modem, that would be an interesting test. The cable in the wall might go a much longer distance, and be of older vintage. The newer ones usually have lower loss, due to improved dielectrics. At least that is the way it is in my house.

I think that RCN can do a diagnostic by just looking at your cable modem signals remotely. They probably won't send a tech out unless they decide that something is really wrong. I expect you can do that over the phone, but it would probably help to give them your Modem MAC address, at the bottom of the speed test page.

I'm not sure how I'd go about connecting straight to the RCN line... I guess I could bring a laptop down there and connect that way if that's what you're talking about, straight into the modem from where it comes into the house.

If you get a TV cable, as from Radio Shack, a length of 50 feet would be OK. You could run that from the RCN cable to your cable modem. I have used new cable runs to reduce the loss to my cable modem and TVs, and it helps.
»www.radioshack.com/family/index.···=4382062

Don't think 50ft would reach, but I see what you're getting at. I'll probably get it from Monoprice.com, much cheaper.

Anyway, here's what happened. I called RCN and told them about it, she had me connect directly to the modem and then asked what speed I was seeing. When I said 13-16mb/s, she told me 16mb/s would be exactly 60% of what I'm paying for and that that's all they guarantee. Then I told her that when I connected directly to the line coming into the house I saw an immediate 24mb/s and she started up a ticket about it.

I'm going to give them a day or so to see if anything gets better, and then I'm going to take my laptop to the basement and physically connect the modem to the incoming line. If the signals are that much better, then I know it's the length of cable coming up to my room and I'll buy 100ft of RG6 and replace it in the wall.

One way or another I'm going to get this fixed, I do appreciate the help.
--
Intel X3350 Quad@3.6GHZ
Abit IP35 Pro
4096MB of Gskill
320GB+500GB SATA
nVidia 8800GTS 512MB OC

Yes, it takes some perseverance, and you have to do most of it yourself. Good luck.

Well, it's definitely the garbage cable in the house. I took my netbook downstairs with my modem and connected the incoming line directly to the modem and got the results in the picture.



Though for the first time ever, my Forward Power is in the green during my normal config, albeit barely at -11dB. Maybe RCN actually did something too.