@toolcubed you're DOCSIS 3.0 signal to noise ratios are a little low. Ideally they would range from 36 to 40 dB. The modem should be running DOCSIS 3.1 so those values should be a moot point, however, I've seen my modem kick over to DOCSIS 3.0 mode recently so those DOCSIS 3.0 channels do come into play and if and when that happens, then those signal to noise ratios will be more important.
I'd keep an eye on them over the next few days to see if they settle out at a higher range, and if not, call tech support and have a discussion with the Customer Service Rep. Since nothing has changed at your end, this is as a result of the work at the local node.
Hello @bfwaye,
Thanks for posting your signal levels!
The signal levels are well within the specified ranges, the minus values you see for the Downstream channels are totally fine.
The acceptable signal range for the Downstream channels is -10 to 10 but you really want to be closer to -7 to 7 to account for signal loss due to poor weather or other external factors. Closest to 0 is the ideal signal strength for the Downstream channels.
For the Upstream channels, the acceptable range is between 36 to 51. You are getting a bit close to that threshold on the Upstream channels but you are still within specification.
Are you noticing any specific issues with your service that we can troubleshoot?
We look forward to your response!
RogersTony
Ouch, not good at all. Are those levels with the modem in the basement, or after you have moved the modem upstairs? For the downstream, you should see something like the following, all of the way down thru the chart:
|
Port ID |
Frequency (MHz) |
Modulation | Signal strength (dBmV) |
Channel ID |
Signal noise ratio (dB) |
| 1 | XXX000000 | 256QAM | 0 (realistically within a +/- 7 dBmV range) | X | 36 to 40 |
Your downstream signal levels are terrible, but, the first question is, where is the modem, in its original install location, or has it been moved?
The upstream isn't great either. The upstream signal level, for this modem, when its running DOCSIS 3.1, should be in the 30 to 33 dBmV range.
Can you post the OFDM section of the table as well please.
If the modem is still in its original install location, call tech support and ask the CSR to run a signal check on the modem. That check will fail automatically, at which point the CSR should arrange a tech visit to determine what the problem is.
If you've moved the modem, can you move it back to its original location and post the same table, including the OFDM and OFDMA sections.
Edit: In terms of the modem location, you are correct, it can be installed anywhere in the home where there is a cable port nearby. The tech will ensure that the modem signal levels are correct, inbound at the modem and outbound at the neighborhood node. Usually the modem's cable is connected to the port on a splitter or powered amplifier that provides the least amount of signal drop. In the case of a two port splitter, it doesn't matter as both ports have the same output. For three ports or more, up to a point, there should be one port that is marked -3.5 dB, which is the preferred port. When you get to larger multi-port splitters, the drop is all the same. At that point the tech will probably cascade splitters to keep the modem signal drop to a minimum. For power amps, there is one port marked for VOIP use. That port is not amplified and is used for both VOIP and modem purposes.
For the upper DOCSIS 3.0 channels, the signal level, ideally would be centered around 0 dBmV with a signal to noise ratio in the 36 to 40 dB range.
The OFDM channel should show one channel active.
The upstream signal level should be in the 30 to 33 dBmV range.
Signal levels such as yours are typically the result of external cable and/or connector failures. The external cable and connectors degrade over the years due to weathering effects, so, every once in a while they require replacement. This might be nothing more than a connector issue, or, it might require a new external cable. The tech will determine what is required.
Just to note, the 4582 is a DOCSIS 3.1 modem. Your modem isn't running DOCSIS 3.1 as seen by the two inactive OFDM channels. Usually there is one OFDM channel running. Looking at your signal levels, the DOCSIS 3.0 levels show that there is a problem in the 500 Mhz range. The OFDM channel typically runs in the 300 to 500 Mhz range on the Rogers network, so, given the fact that the OFDM channel isn't running, the 500 Mhz range DOCSIS 3.0 levels are poor, and your upstream levels are higher than normal, that indicates that there is major signal degradation problem in the lower 500 Mhz range on your inbound cable. Your cable signal levels are poor overall, but, the lower frequency range is probably worse than what you see in the upper 500 Mhz range.
To make a long story short, you need a tech. When the tech has completed the required work, you should see signal levels as indicated above, the OFDM channels should show one OFDM channel active and the modem's front download LED should be a lighter blue in colour, indicating that the modem is using DOCSIS 3.1. The active OFDM channel should match up with the front LED downstream colour. Inactive OFDM plus downstream LED the same colour as the upstream LED indicates that the modem is running DOCIS 3.0 on the downstream side. Active OFDM channel plus light blue downstream LED indicates that the modem is using DOCSIS 3.1 on the downstream side.
When this is all said and done, can you repost the signal levels again. Sometimes this takes more than one tech visit. It might in fact be an issue with the local tap, which connects all of your immediate neighbours, or it could be a problem further upstream. If you're still having issues after the tech has gone, don't hesitate to call tech support again, and at any time.
If you would prefer to move the modem upstairs, and a serviceable cable outlet is available, ask the tech to move the modem. I don't believe there should be any cost to this as the tech is already onsite for signal problems. If the cable is an RG-6 cable, and its serviceable, then it should be a matter of connecting that cable to a splitter if you already have additional services. This only becomes complicated if the cable is already used for another service. Then its a matter of ensuring that the modem signal level drop that is due to the splitters is minimized. That's where the tech's creativity and experience enters the picture.
Nope, don't do that. There are two styles of amps that are in use these days. The older amps will amplify everything. They will also cause packet loss. The newer amps have an internal passive splitter. One leg goes to the VOIP port. The other leg goes to the amplifier and then out to the other ports. The VOIP phone or modem is connected to the passive port to avoid packet loss.
The biggest problem with splitters, personal opinion, is that they hide bad signal conditions and amplify any noise that is in the cable system. So, I would guess that your cable set top boxes are working and that you may or may not see any problems.
The results for the modem might improve slightly depending on which port the modem cable is connected to. That splitter probably has one port marked -3.5 db and two ports marked -7 dB. That indicates the loss on each port, with -3.5 dB being the lowest signal loss. The cable modem should be connected to that port.
The solution here is to take care of the losses before they arrive at that splitter. So, the field techs and maintenance crews have to ensure that there is no excessive losses in the system, right up to that splitter. If the tech can't resolve the low signal conditions, then a maintenance crew should be called in to take care of any upstream losses. This is where persistence on your part comes in. If the first or second tech can't get it right, don't hesitate to call tech support again, and again ...... For now, we'll see how the first visit goes.
I noticed a error in my previous response.
Where it reads: "The biggest problem with splitters"
Should read: The biggest problem with amplifiers, personal opinion, is that they hide bad signal conditions and amplify any noise that is in the cable system.
My apologies for the confusion. The amplifier hides those issues, which is why you probably don't see any problems with the set top boxes. The modem however, running thru the splitter is subject to the low signal levels and poor signal to noise ratios. That's a direct result of the cable and/or connector issues.
The only time that you will probably see an amplifier ahead of a modem is if you happen to be the last customer(s) on the cable run from the local node. That cable run can result in less than stellar signal levels. The only way to resolve that would be to increase the initial signal levels, which poses problems for customers who are much closer to the node. So, the initial output signal levels are a happy medium so to speak, to service customers along the entire cable run.
Ugh!! That is terrible. All of the DOCSIS 3.0 channels with 4.191 as a Signal to Noise ratio, shouldn't be that way. Note that those levels are all in the 500/600 Mhz range. If you look carefully at the channel frequencies, you can see those channels sitting very close to channels that are acceptable, so, something's up, so to speak. Your DOCSIS 3.1 OFDM channel isn't running, indicating that the channel won't support DOCSIS 3.1 operation. That channel starts around 300 Mhz and runs up to approx 492 Mhz. So it looks like you have problems in the lower 500 Mhz range with that particular cable run. If that's the best of the bunch, you have problems.
The DOCSIS 3.0 upstream levels are higher than normal as well for that modem. Typically their down around 30 to 32/33 dBmV. So you have a couple channels which are slightly higher, with a larger spread (33 to 39 dBmV) than is normal.
So at the present time, you don't have DOCSIS 3.1 downstream running which is designed to deliver higher data rates, and you're effectively running with a reduced set of DOCSIS 3.0 channels for downstream operation. The upstream levels shouldn't be an issue.
So, the question of the day, would you happen to know if your house cabling is RG-59 or RG-6? If you look in the basement, where those cables converge, you should be able to read the cable type which is imprinted on the cable jacket. Ideally that should be RG-6. RG-59 has higher losses in the higher frequency range.
I'd be interested in seeing the signal levels with the modem connected to the incoming cable in the basement. That would answer the question of whether or not the signal levels are bad due to house wiring or if they're already in poor condition before they arrive in the basement.
Is all of the house cabling internal to the house? Are there any cables that exit the home, and then re-enter the home at other locations? If there were any cable runs on the outside of the house, then those cables would be subject to weathering over the years and might need replacement.
When the modem is running DOCSIS 3.1 on the downstream side, the front downstream LED will be a lighter blue in colour, its supposed to be magenta. In the signal level table, that light blue LED should be accompanied with one OFDM channel showing as active. There is only one OFDM downstream channel in operation at the present time. Upstream DOCSIS 3.1 as shown in the bottom OFDM/OFDMA section isn't in operation yet. Rogers is still testing Upstream 3.1, as is all of the other ISPs who happen to be using DOCSIS 3.1. Techs from ISPs will staple cabling around the edge of rooms, but won't fish cables thru walls and floors.
I suspect that your cables will be RG-59, given how old the house is. You'll know soon enough. If thats the case, you should consider calling in an electrician or company that does internal cable replacement and pull RG-6 cables where its possible. No ISP will do that, so its really up to the home owner to install or replace cables that are beyond the demarcation point.
You'll also know what the situation is when you're able to connect the modem to the incoming cable in the basement.
Just as a note, I'm surprised that the tech didn't say anything to you about the DOCSIS 3.1 channel. It would be interesting to see what the test equipment indicated, but, I have a hard time believing that it was ok on the test equipment, given that the modem won't run the OFDM channel. The two results should be comparable, otherwise, what the point of the test equipment?
-
78507 views
-
21 Likes
-
-
