What are good signal levels

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I'm a Regular
Posts: 305

Re: What are good signal levels

UPDATE to my post above. I introduced a Rogers-certified 2 way splitter. Line coming into the house going into 2 way splitter. One -3.5db port to CODA, the other -3.5db port into Antronix amp where home phone and 2 TVs are connected. CODA levels are now back to normal. The 32 channels are around 0db, SNR are mostly 37 (some are 38), and the three upload channels are 37, 38, and 41. OFDM signal is a solid 0.3db Smiley Happy Now I just have to keep an eye on the TVs to make sure there aren’t any issues because signal (when looking at diagnostic menu on NB3 boxes) dropped to -4 to -5 for most channels.
I Plan to Stick Around
Posts: 11

Re: What are good signal levels

@Dragus wrote:

Is my DOCSIS WAN readings bad?


I've seen peoples DOCSIC usually -/+5 from 0 in signal strength. Read from another post that signal noise should be between 36-38.


I've been checking multiple times a day since May 16 to confirm it's consistent throughout the day.


Does bridge mode affect any of these values?


Running CGN3ACSMR and I think my download speeds are pretty consistent from when i've been downloading. Occassionally I may experience some redbar lag on my PS4 but can't confirm if it's on my end or on PSN/Destiny side.


Downstream Overview
Port IDFrequency (MHz)ModulationSignal strength (dBmV)Channel IDSignal noise ratio (dB)
Upstream Overview
Port IDFrequency (MHz)ModulationSignal Strength (dBmV)Channel IDBandWidth
123700000ATDMA - 64QAM44.00036400000
230596000ATDMA - 64QAM44.00026400000
338596000ATDMA - 64QAM44.00013200000

The outside cabling and connectors don't keep going forever and now and then a tech visit is required to supplant them. That is an exceptionally typical event despite the fact that it for the most part takes quite a while until the point when the link break down to a point where it requires consideration.

I'm Here A Lot
Posts: 7

Re: What are good signal levels

Hitron CODA-4582U Signal Levels


Hey guys - I was looking for some help/advice about my Hitron CODA-4582U cable modem. Rogers set it up in the basement, however, I was looking to move it to another part of the house. I was reading about signal levels and was wondering if anyone knew if the following output was considered good/satisfactory/bad. 


What am I looking for with the dBmV values for downstream and upstream? What should the Signal Noise Ratio be? Any help is greatly appreciated!


Downstream Overview

Port ID Frequency (MHz) Modulation Signal strength (dBmV) Channel ID Signal noise ratio (dB)
1 603000000 256QAM -12 9 35.084
2 849000000 256QAM -16.1 2 33.487
3 855000000 256QAM -15.7 3 33.487
4 861000000 256QAM -16.1 4 33.377
5 579000000 64QAM -11.6 5 4.191
6 585000000 64QAM -11.6 6 4.191
7 591000000 64QAM -11.3 7 4.191
8 597000000 64QAM -11.8 8 4.191
9 603000000 64QAM -6.2 1 4.191
10 609000000 64QAM -11.8 10 4.191
11 615000000 256QAM -12.1 11 35.084
12 621000000 256QAM -12.4 12 35.084
13 633000000 256QAM -11.1 13 35.595
14 639000000 256QAM -10.9 14 35.78
15 645000000 256QAM -10.7 15 35.78
16 651000000 256QAM -10.9 16 35.78
17 657000000 256QAM -11.3 17 35.78
18 663000000 256QAM -11.2 18 35.78
19 669000000 256QAM -11.1 19 35.78
20 675000000 256QAM -11.2 20 35.78
21 681000000 256QAM -11 21 35.595
22 687000000 256QAM -10.8 22 36.387
23 693000000 256QAM -10.9 23 35.78
24 699000000 256QAM -11.3 24 35.595
25 705000000 256QAM -11.5 25 35.78
26 711000000 256QAM -11.9 26 35.78
27 717000000 256QAM -12 27 35.78
28 723000000 256QAM -11.9 28 35.78
29 825000000 256QAM -14.8 29 34.484
30 831000000 256QAM -15.4 30 33.957
31 837000000 256QAM -15.8 31 33.834
32 843000000 256QAM -15.5 32 33.957


Upstream Overview

Port ID Frequency (MHz) Modulation Signal strength (dBmV) Channel ID Bandwidth
1 23700000 ATDMA - 64QAM 39.25 5 6400000
2 38596000 ATDMA - 64QAM 45.25 6 3200000
3 30596000 ATDMA - 64QAM 41.5 4 6400000


Thank you,


Resident Expert
Resident Expert
Posts: 6,052

Re: What are good signal levels

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:






Modulation Signal strength (dBmV)



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. 

I'm Here A Lot
Posts: 7

Re: What are good signal levels

Thanks for the info. The cable modem has remained in the basement since the day I got it connected. I wanted to understand if I was getting a decent connection in the basement before exploring other options. I contacted Rogers about this and they ran a test to check the signal levels. They offered to have someone come out to the house to try and correct the issue. What are the acceptable levels for the metrics below? Could this be a result of the cable running to the modem? Or is this a wider issue with the cabling on the property? 


I have posted today's data below: 


Downstream Overview
Port IDFrequency (MHz)ModulationSignal strength (dBmV)Channel IDSignal noise ratio (dB)
OFDM Downstream Overview 
ReceiverFFT typeSubcarr 0 Frequency(MHz)PLC lockedNCP lockedMDC1 lockedPLC power(dBmv)


Upstream Overview

Port IDFrequency (MHz)ModulationSignal strength (dBmV)Channel IDBandwidth
123700000ATDMA - 64QAM41.7556400000
238596000ATDMA - 64QAM42.7563200000
330596000ATDMA - 64QAM40.2546400000



Channel IndexStatelin Digital AttDigital AttBW (sc's*fft)Report PowerReport Power1_6FFT Size

Thanks again,


Resident Expert
Resident Expert
Posts: 6,052

Re: What are good signal levels

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. 

I'm Here A Lot
Posts: 7

Re: What are good signal levels

So I went down to the electric closet in the basement and noticed that there is a powered amp connected, but not to the internet line. The power amp was connected to another 3 way splitter that services the tvs upstairs. Temporarily I connected the internet line to powered amp and got the following results. Are these satisfactory, or is there something you see that could improve?

Downstream Overview
Port ID Frequency (MHz) Modulation Signal strength (dBmV) Channel ID Signal noise ratio (dB)
1 603000000 256QAM 2.600 9 36.387
2 849000000 256QAM -1.700 2 36.610
3 855000000 256QAM -1.500 3 36.610
4 861000000 256QAM -1.800 4 36.387
5 579000000 256QAM 2.700 5 36.610
6 585000000 256QAM 2.900 6 36.610
7 591000000 256QAM 3.100 7 36.610
8 597000000 256QAM 2.600 8 36.610
9 303000000 256QAM 7.900 1 37.356
10 609000000 256QAM 2.600 10 36.610
11 615000000 256QAM 2.300 11 36.610
12 621000000 256QAM 2.100 12 36.610
13 633000000 256QAM 3.400 13 36.610
14 639000000 256QAM 3.400 14 37.356
15 645000000 256QAM 3.700 15 37.356
16 651000000 256QAM 3.400 16 37.356
17 657000000 256QAM 3.100 17 37.356
18 663000000 256QAM 2.800 18 37.356
19 669000000 256QAM 3.000 19 37.356
20 675000000 256QAM 2.700 20 37.356
21 681000000 256QAM 2.900 21 37.356
22 687000000 256QAM 3.300 22 37.636
23 693000000 256QAM 3.100 23 37.636
24 699000000 256QAM 2.800 24 37.356
25 705000000 256QAM 2.300 25 37.636
26 711000000 256QAM 2.100 26 37.636
27 717000000 256QAM 1.700 27 37.636
28 723000000 256QAM 2.100 28 37.636
29 825000000 256QAM -0.500 29 37.636
30 831000000 256QAM -1.200 30 36.610
31 837000000 256QAM -1.400 31 37.356
32 843000000 256QAM -1.200 32 37.356
OFDM Downstream Overview
Receiver FFT type Subcarr 0 Frequency(MHz) PLC locked NCP locked MDC1 locked PLC power(dBmv)
1 4K 275600000 YES YES YES 7.599998
Upstream Overview
Port ID Frequency (MHz) Modulation Signal strength (dBmV) Channel ID Bandwidth
1 23700000 ATDMA - 64QAM 40.750 5 6400000
2 38596000 ATDMA - 64QAM 44.500 6 3200000
3 30596000 ATDMA - 64QAM 40.750 4 6400000
Channel Index State lin Digital Att Digital Att BW (sc's*fft) Report Power Report Power1_6 FFT Size
0 DISABLED 0.5000 0.0000 0.0000 -inf -1.0000 4K
1 DISABLED 0.5000 0.0000 0.0000 -inf -1.0000 4K
Resident Expert
Resident Expert
Posts: 6,052

Re: What are good signal levels

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'm Here A Lot
Posts: 7

Re: What are good signal levels

Thanks so much for the info! I have a Rogers tech coming out to my place this Sunday. Will post an update once they're done. Hopefully this is something they can resolve easily, and during the first visit. 

Resident Expert
Resident Expert
Posts: 6,052

Re: What are good signal levels

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.