Question What should my cable modem signal levels be? (Downstream Power Level)

[chesterwchanco]

Hey guys I would like to ask if my cable internet connection stats above are normal? I experience intermittent connection atleast 5 times a day this only happen for the month of July and August. We are using a splitter for our TV and Internet, our ISP already sent a technician and have a look on our problem but when he visited the internet was fine. The tech also told me that downstream power should be atleast -3 to -6 to become more stable? I'm not sure if he is correct because this only happen within those month and we're already subscribed to this ISP for more than 3yrs already. One more thing he also suggests that we generate a new special line that will be direct from their line to our modem without connecting to the splitter so the splitter will be used for the tv only. (screenshot above was taken 3pm)

Hoping for anyone can help my problem. Thanks

 

[chesterwchanco]

As of now this is the new downstream level (1am time)

 

[bill001g]

Looks like you have a connection that is being affected by heat. Could be in/on your house or someplace in the street.

There are tables that show the recommended values and it varies a bit based on the encoding.

The one that breaks things for most people is the upstream power levels. This needs to be under 50 to really be stable for 3 upstream channels. It will work higher but if it gets to say 52 or 53 it almost always fails.

Your downstream levels are bad in both cases. You want as close to zero as you can get. The recommended numbers are not exact but commonly -7 to +7. It will break if it goes below -15 or above +15 but it would be really rare to get a + number that strong.

I would connect the modem at the point the cable comes into the house. This will show you the best possible values you can expect. It will show if there is some issue with cables in your house. This is to avoid the ISP coming out and charging you because it your house wiring.

If you get crap numbers hooked up where the cable comes in call the ISP and talk to them. They can see these numbers remotely and even the level 1 techs know what the recommended values are.

 

[chesterwchanco]

Looks like you have a connection that is being affected by heat. Could be in/on your house or someplace in the street.

There are tables that show the recommended values and it varies a bit based on the encoding.

The one that breaks things for most people is the upstream power levels. This needs to be under 50 to really be stable for 3 upstream channels. It will work higher but if it gets to say 52 or 53 it almost always fails.

Your downstream levels are bad in both cases. You want as close to zero as you can get. The recommended numbers are not exact but commonly -7 to +7. It will break if it goes below -15 or above +15 but it would be really rare to get a + number that strong.

I would connect the modem at the point the cable comes into the house. This will show you the best possible values you can expect. It will show if there is some issue with cables in your house. This is to avoid the ISP coming out and charging you because it your house wiring.

If you get crap numbers hooked up where the cable comes in call the ISP and talk to them. They can see these numbers remotely and even the level 1 techs know what the recommended values are.

I will look into that heat since our modem is inside the AC room.

I see the tech already visited earlier and do some stuff and he tried to change the cable this one is direct from the line and it is providing atleast -3dB to -7dB (forgot to screenshot earlier). So should I take his suggestion and generate a special line this line will be from the post and it will be direct to our modem because our current one is connected with a splitter. Is -3dB to -7dB good compare to my current one which is -11dB?

Also did you check my current one with the top comment? as of now I'm having -8dB to -10dB

 

[bill001g]

You might just need a different splitter. So they recommend running 2 lines from outside to your house ? I guess if they want to do it for free I would let them. All depends on how long before they raise the rates on the tv again and you join all the people watch cable over their internet connection.

 

[chesterwchanco]

You might just need a different splitter. So they recommend running 2 lines from outside to your house ? I guess if they want to do it for free I would let them. All depends on how long before they raise the rates on the tv again and you join all the people watch cable over their internet connection.

Yes 2 lines outside the house one will be the current one we are using it now for TV + Internet(Splitter) and the other one (which the tech suggest) tap a new line direct to our modem-router so that line will be for internet purpose only and we did a test run earlier and it gave me a result of -3dB vs -11dB earlier and -8dB now. I haven't tested the stability though since we just check the new line for just 5mins and earlier I don't face any problem with my internet connection.

For the TV rates though we are not really paying it since it is bundled with our internet its free btw

 

[dengamle]

Your numbers don't reveal why you are having problems. The modem is operational at -12 dBmV, and your SNR numbers are great. The event log might have more details.

 

[chesterwchanco]

Your numbers don't reveal why you are having problems. The modem is operational at -12 dBmV, and your SNR numbers are great. The event log might have more details.

Thanks I'll upload the event log later by the way what is the ideal downstream power level is it true that it must be close to Zero? I found some article on the internet that -3dB is the best and any -5dB to -15dB are not that great or will cause non stable or intermittent connection.

 

[dengamle]

0 dBmV is said to be ideal (a reference point). -15 dBmV is not really great (and should be avoided) and breaks more easily when noise is present. Your -12 dBmV is not a great value, but your SNR indicates a rather clean line. Unfortunately, your modem doesn't show codeword stats (bit errors), so you don't know if there is intermittent noise.

 

[chesterwchanco]

0 dBmV is said to be ideal (a reference point). -15 dBmV is not really great (and should be avoided) and breaks more easily when noise is present. Your -12 dBmV is not a great value, but your SNR indicates a rather clean line. Unfortunately, your modem doesn't show codeword stats (bit errors), so you don't know if there is intermittent noise.

I'm a bit curious why is that during 12PM to 11PM afternoon to evening(peak hour) -dBmV goes up like -7 to -11 while during 12MN to 10AM midnight to morning I get around -3 to -6 which is giving me a fast and stable connection compare to higher dBmV during peak hours.

 

[bill001g]

I am not sure if traffic causes this to increase I don't think it does.

It very well could be heat related. There could be a connector someplace in the path that expands just a bit when its hot and makes less contact. I guess it depends where you live and how hot it gets.

 

[chesterwchanco]

I am not sure if traffic causes this to increase I don't think it does.

It very well could be heat related. There could be a connector someplace in the path that expands just a bit when its hot and makes less contact. I guess it depends where you live and how hot it gets.

I see, I don't think its the heat since our modem is inside an AC room i think the splitter is the issue with the increase value of dBmV? Anyway this coming Sunday we will generate a new line to my modem this time there will be no splitters(we have cable subscription from our ISP) it will be only for internet line. I hope this will fix the intermittent connection and slow downs during peak hour

 

[dengamle]

Hm. My eyes missed the modulation order in your upstream. 64-QAM is common today. It can be lower due to noise. Channel 3 is only 8-QAM in the 2nd picture. Something is going on there. Let's see the stats with the new cable.

 

[chesterwchanco]

So the new line was created and these are the stats. I hope that it will fix the intermittent connection so far within 24hrs there's a huge improvement from the previous line with splitter particularly in loading sites and ping in game.

 

[chesterwchanco]

Hm. My eyes missed the modulation order in your upstream. 64-QAM is common today. It can be lower due to noise. Channel 3 is only 8-QAM in the 2nd picture. Something is going on there. Let's see the stats with the new cable.

Hi can you check my new stats above?

 

[dengamle]

Your downstream numbers are perfect now. I'm just worried about the low modulation in your upstream. If you still have problems, you probably need to talk to your provider. It might not be a problem you can fix yourself.

 

[chesterwchanco]

Your downstream numbers are perfect now. I'm just worried about the low modulation in your upstream. If you still have problems, you probably need to talk to your provider. It might not be a problem you can fix yourself.

What is low modulation? I don't understand it from my stats though I don't encounter any problem on my upload and upload speed it is always 10% of my download and it is the same with other users here in our country.

 

[dengamle]

It is about how many bits per unit you can transmit. QAM8 is very low modulation. Noise dictates how high it can be. You might not see any problems, because it is this low and therefore can cut through the noisy upstream.