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Fordguy

join:2012-07-16
Portsmouth, VA

[VA] modem Levels

I haven't had a D3 modem for long (3 or so months) but here are my levels. Should each channel be a different power level or should they be the same. I have called cox and the guy on phone said levels are within spec of -10 to +10 and each channel will be different because of different frequency. Any input would be appreciated and thanks in advance

DPC-3010

Power Level: Signal to Noise Ratio:
Channel 1: -1.4 dBmV 40.3 dB
Channel 2: -1.7 dBmV 39.9 dB
Channel 3: -1.9 dBmV 39.3 dB
Channel 4: -9.4 dBmV 36.5 dB
Channel 5: -9.6 dBmV 36.3 dB
Channel 6: -9.8 dBmV 35.6 dB
Channel 7: -10.3 dBmV 35.6 dB
Channel 8: 0.0 dBmV 0.0 dB

Upstream Channels

Power Level:
Channel 1: 39.5 dBmV
Channel 2: 39.5 dBmV
Channel 3: 39.5 dBmV
Channel 4: 39.5 dBmV


m8trix

join:2003-12-24
Phoenix, AZ
kudos:4

correct each channel will have its own signal level how ever channel 4-7 are barely with in range and may cause problems


Fordguy

join:2012-07-16
Portsmouth, VA
reply to Fordguy

In the faqs about lvls it says

all downstream channels should be within a +/-2db window with respect to each other

what would cause channels 4-7 to be so far off compared to 1-3?

I get the same difference weather connected as is or straight to the outside cable box. thanks again


signcarver

join:2005-03-20
Phoenix, AZ

When the faq was put out, they were mainly talking about modems that bond 4 channels as the 4 channels are tuned by the same tuner. The 8 channel versions usually have 2 32Mhz tuners, each of these tuners must have it's 4 channels in the +/-2db window.

In your case, more than likely, one tuner is tuning channels 1-3 and another 4-7.


lilstone87

join:2009-04-09
Portsmouth, VA
kudos:3
Reviews:
·Cox HSI
reply to Fordguy

said by Fordguy:

In the faqs about lvls it says

all downstream channels should be within a +/-2db window with respect to each other

what would cause channels 4-7 to be so far off compared to 1-3?

I get the same difference weather connected as is or straight to the outside cable box. thanks again

Hey I am also from portsmouth myself, and some of your signal levels are borderline. But unless your having trouble nothing to worry about. The reason 3 of your downstream channels have lower power levels, is because them three channels are in the 500mhz range, while the 4 channels with -9 to -10db power levels is in the 800mhz range. So yes it is normal for these channels power levels to be different when frequency range is that far apart. As for me saying some of your signal levels are borderline, with D3 they want downstream power levels between -10 to 10db max, closer to 0 the better. Also your 800mhz downstream channels are on the low side with downstream SNR specs, which cox likes minimum of 35db. Anyways if you are having no problems, let it be. But if you do start to have problems, signal levels do have a little room for improvement.

lilstone87

join:2009-04-09
Portsmouth, VA
kudos:3
Reviews:
·Cox HSI

Click for full size
Here is a screenshot of my signal levels on the same exact channels you are connected to, so you can see the difference.

Fordguy

join:2012-07-16
Portsmouth, VA
reply to Fordguy

Ok thanks for the replies!

heres my levels with just the modem hooked up from the pole.

DPC-3010

Power Level: Signal to Noise Ratio:
Channel 1: 6.8 dBmV 39.1 dB
Channel 2: 6.8 dBmV 39.1 dB
Channel 3: 6.6 dBmV 38.5 dB
Channel 4: 0.2dBmV 36.3 dB
Channel 5: -0.2 dBmV 36.1 dB
Channel 6: -0.5 dBmV 36 dB
Channel 7: -0.8 dBmV 35.6 dB
Channel 8: 0.0 dBmV 0.0 dB

Upstream Channels

Power Level:
Channel 1: 32.5 dBmV
Channel 2: 32.5 dBmV
Channel 3: 32.5 dBmV
Channel 4: 32.5 dBmV

Are these good starting numbers?

The line to the modem comes into the house off a 2-way splitter and goes into another 2-way which one side goes to dvr and other goes to modem and gives me my original posted levels. (I better not thank about how I can reconfigure my splitters now or ill be up all night)

It works ok i guess, just dont like being on the edge, but as long as the starting levels are good may play with the splitters or just let it go till modem has problems connecting. Thanks for the replies!



CoxTech1
VIP
join:2002-04-25
Chesapeake, VA
kudos:76
reply to Fordguy

The +/-2db window spec is per bonding group. If you pay attention to the frequencies I suspect you'll see that the channels with better levels are likely in the 500Mhz group and the ones barely in spec are in the 800Mhz group.


Fordguy

join:2012-07-16
Portsmouth, VA
reply to Fordguy

It been 2 weeks since originally posted and been monitoring modem levels everyday. Checked to day and found the below levels.

Power Level: Signal to Noise Ratio:
Channel 1: -3.0 dBmV 38.7 dB
Channel 2: -3.4 dBmV 38.6 dB
Channel 3: -3.6 dBmV 38.4 dB
Channel 4: -11.2 dBmV 35.5 dB
Channel 5: -11.5 dBmV 35.2 dB
Channel 6: -11.7 dBmV 34.9 dB
Channel 7: -12.2 dBmV 34.9 dB
Channel 8: 0.0 dBmV 0.0 dB

Upstream Channels

Power Level:
Channel 1: 38.2 dBmV
Channel 2: 38.2 dBmV
Channel 3: 38.2 dBmV
Channel 4: 38.2 dBmV

(levels seem to be about -2 to -3 dBmV from original post)

Only thing so far Ive done was changed splitters and ran new rg6 line to cable modem which was done the weekend before original post.

coxtech1 is there possible a node issue or a problem at the tap. Only thing I find outside is a old crimp connection on cox's side of the interface box (which I don think im aloud to disconnect).

If things appear to be working correctly (cant check for modem reboots as dcp3010 doesn't allow me to see logs) should I be to concerned? Any input would be appreciated


lilstone87

join:2009-04-09
Portsmouth, VA
kudos:3
Reviews:
·Cox HSI

said by Fordguy:

It been 2 weeks since originally posted and been monitoring modem levels everyday. Checked to day and found the below levels.

Power Level: Signal to Noise Ratio:
Channel 1: -3.0 dBmV 38.7 dB
Channel 2: -3.4 dBmV 38.6 dB
Channel 3: -3.6 dBmV 38.4 dB
Channel 4: -11.2 dBmV 35.5 dB
Channel 5: -11.5 dBmV 35.2 dB
Channel 6: -11.7 dBmV 34.9 dB
Channel 7: -12.2 dBmV 34.9 dB
Channel 8: 0.0 dBmV 0.0 dB

Upstream Channels

Power Level:
Channel 1: 38.2 dBmV
Channel 2: 38.2 dBmV
Channel 3: 38.2 dBmV
Channel 4: 38.2 dBmV

(levels seem to be about -2 to -3 dBmV from original post)

Only thing so far Ive done was changed splitters and ran new rg6 line to cable modem which was done the weekend before original post.

coxtech1 is there possible a node issue or a problem at the tap. Only thing I find outside is a old crimp connection on cox's side of the interface box (which I don think im aloud to disconnect).

If things appear to be working correctly (cant check for modem reboots as dcp3010 doesn't allow me to see logs) should I be to concerned? Any input would be appreciated

Have you had a tech out? Reason I ask, is because I will have to admit, with some of the D3 changes cox did in our area. They did not do that good of a job at rebalance of signal levels. So if you are getting these readings directly from the line coming from the street without any splitters. Its something cox needs to do on there end to balance levels before, and/or at the tap. Sadly if you want your signal levels better, you will need a tech visit. So he can confirm for sure or not that signal levels are not ideal before reaching your home. Which then he could put in a ticket for signal levels to be adjusted at the street level. Anyways if your connection isn't having any problems, I wouldn't worry to much about it.

Fordguy

join:2012-07-16
Portsmouth, VA
reply to Fordguy

No sadly this is not straight from the street, these are levels coming off the -3.5 side of a 3-way then off a 2-way (-3.5 of course). The second half of 2-way goes to hd/dvr setup.

I have drawn out every possible way to try to eliminate a splitter and the way it is, is the best way(in respect to the -db drop from splitters) with out dropping the hd/dvr and one other digital box to much. Whether the hd and the digital boxes can take a db drop without causing problems im not sure without calling cox to come out and test it.

Like you said if it works then its all good I guess.

One other thought does cox periodically check the condition of the overhead cable wires, all the utility poles are on the other side of street where there are plenty of trees that rub against the cable lines, some reach up to the lower power lines and cause arcing doing storms.


Beezel

join:2008-12-15
Las Vegas, NV
reply to Fordguy

If possible you should have the modem coming straight off the first splitter by itself straight to the modem. Then on the other side of the splitter you can run for the DVR and boxes. Just a opinion. But that would help the power levels a bit.