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Visitor
Captagro
Posts: 2
Registered: ‎04-04-2011

Motorola SB6120 Cable Modem

Anyone using a Motorola SB6120 cable modem? Any setup problems?

Connection Expert
EG
Posts: 42,116
Registered: ‎12-24-2003

Re: Motorola SB6120 Cable Modem

Yes. And no. What exactly do you mean by "setup" problems ?

Regular Problem Solver
Posts: 2,842
Registered: ‎11-02-2003

Re: Motorola SB6120 Cable Modem

Been using a 6120 here for several months now.....

Initially it took 4 or 5 tries to get it re-provisioned after I upgraded to Extreme from Ultra....the CSRs seemed to have a difficult time finding/passing the proper firmware through....once the "hurdle' was cleared, I've had very good results....BTW...I own my modem; I bought it from the local Best Buy and swapped out my (leased) Cisco DPC3000....Good luck!

Official Employee
ComcastSteve
Posts: 384
Registered: ‎09-13-2006

Re: Motorola SB6120 Cable Modem

There are some issues with SB6120 modems provisioning with outdated firmware. Are you having any specific issue with the modem?

Steve Teow


Regular Problem Solver
Posts: 2,842
Registered: ‎11-02-2003

Re: Motorola SB6120 Cable Modem

According to my 6120 modem stats:

 

Firmware: SB612X-1.0.3.3 - SCM00-NOSH

 

Hardware Version: 3.0

 

Firmware Build Date: August 12, 2010  13:58:19

 

This is, I assume, the latest data......?!

Connection Expert
EG
Posts: 42,116
Registered: ‎12-24-2003

Re: Motorola SB6120 Cable Modem

To my knowledge that is indeed the latest firmware load to have been pushed. Wonder if Steve was replying to the OP or to dsanbo ?

Official Employee
ComcastSteve
Posts: 384
Registered: ‎09-13-2006

Re: Motorola SB6120 Cable Modem

I meant to reply to OP

Steve Teow


New Visitor
Knteshade
Posts: 1
Registered: ‎04-09-2011

Re: Motorola SB6120 Cable Modem

[ Edited ]

I currently have the SB5120 modem. Is it worth getting the SB6120? I was unsure if DOCSIS 3 was available or usable everywhere yet.

Contributor
Posts: 5
Registered: ‎01-15-2009

Re: Motorola SB6120 Cable Modem

I picked up a new sb6120 from Amazon a couple weeks ago and have been noticing some strange things.  First off, my incoming connections seem to come and go.  Sometimes I can connect over RDP to my house from work, sometimes I can't.  If I run a port scan, sometimes 3389 is open, sometimes it isn't.  A tracert stops responding at 68.86.183.142.  There are also intermittent connection drops browsing from inside the house, https seems much more prone to hangups than non-ssl sites, and RDP connections going out to a work server just flat out barf on me.  My current dl/ul speeds are 15Mb/s 8Mb/s (much higher upload than I excpected, not that I'm complaining).  Has anybody seen anything similar?

New Visitor
MAL159
Posts: 3
Registered: ‎04-14-2011

Re: Motorola SB6120 Cable Modem

It seems that this is a common problem with COMCAST and the SB6120.  Mine was working OK for 2-1/2 months, then it just suddenly stopped working 4 days ago.  The RECEIVE and SEND lights would be solid green, and the ONLINE light would blink for about 30 seconds, then the modem would reset (only the POWER light on), and the process would start over again and continue indefinitely.

 

A Comcast Tech was here yesterday and said that he has seen the same problem with 3 other customers within the past month.  I was really hoping that it was a service connection problem, because I was trying to save the hefty $7/month rental fee.  As it turned out, the Tech connected a UBEE U10C035 modem, and my connection was up and running without a hitch.

 

I'm past my return period with Amazon, so I had to speak with Motorola since, luckily, the modem is still under warranty.  If I understand Customer Support correctly, my Comcast signal could be "too strong".  They agreed to exchange the modem (my return cost) for a new one, but I suspect that this won't solve the problem.  So I'm stuck with a $80 paperweight, and will now have to pay the rental fee again.  I wish that I could buy a UBEE, but I don't think it's for sale anywhere.  Only the ISPs have them, and you can't buy it from them.  I just wish that Comcast would not put the SB6120 on the approved list and not support it.  Motorola doesn't seem to have a clue on how to fix the problem.

 

My questions to ComcastSteve are:

 

1) What is the common thread as to why so many people are having this SB6120 issue?

 

2) If it's a firmware problem, how can I flash it myself?

Connection Expert
EG
Posts: 42,116
Registered: ‎12-24-2003

Re: Motorola SB6120 Cable Modem

@ mal 159. What firmware load does it currently have ? What do the up and down power levels look like ? You can't "flash" the firmware itself. CC must do it.

New Visitor
MAL159
Posts: 3
Registered: ‎04-14-2011

Re: Motorola SB6120 Cable Modem

EG

 

Firmware Name: SB612X-1.0.3.3-SCM00-NOSH

Boot Version: PSPU-Boot 1.0.0.4m1

Hardware Version: 3.0
Firmware Build Time: Aug 12 2010 13:58:19

 

I have no idea about the up/down power levels and I've already sent back the SB6120 for exchange.

Connection Expert
EG
Posts: 42,116
Registered: ‎12-24-2003

Re: Motorola SB6120 Cable Modem

[ Edited ]

O/k. Well it did have the latest firmware for it anyway which supposedly corrected that problem. It did for me anyway. The reason that I asked about the power levels is because I had found through my own experience and read in a few forums that the 6120 was a bit more sensitive to and less forgiving of marginal and out of spec signals than are others. At one point my downstream power was at +12dB which is not terrible BTW and my 6120 was continuously rebooting spontaneously. I added a 6dB attenuator in the coax line and that cured that problem. Perhaps this was the issue with yours ? Many premise techs would believe that +12dB of receive power was o/k and would let it go at that.

Contributor
Posts: 5
Registered: ‎01-15-2009

Re: Motorola SB6120 Cable Modem

I'm not even getting reboots.  I'm just getting connection timeouts and lags.  I'm also having trouble getting into Remote Desktop from work, just won't get a connection.  I know it's not the router, I know it's not the firewalls, something out there is just blocking my packets from even getting to the router.

Contributor
Posts: 5
Registered: ‎01-15-2009

Re: Motorola SB6120 Cable Modem

I'm also not getting any channel bonding.  Not sure if that's normal or not.

New Visitor
MAL159
Posts: 3
Registered: ‎04-14-2011

Re: Motorola SB6120 Cable Modem

Thanks EG.  I will definitely try the attenuator approach if the new modem gives the same problem.

 

You would think that a large company like Motorola, with many smart Engineers and massive resources at their disposal, would solve the problem.  Instead they rely on the end user to figure things out for themselves.

Connection Expert
EG
Posts: 42,116
Registered: ‎12-24-2003

Re: Motorola SB6120 Cable Modem


temujin2000 wrote:

I'm also not getting any channel bonding.  Not sure if that's normal or not.


Depends on whether or not your particular system has been upgraded to DOCSIS 3 yet. Have you called in to inquire about that ?

Connection Expert
EG
Posts: 42,116
Registered: ‎12-24-2003

Re: Motorola SB6120 Cable Modem


MAL159 wrote:

 

You would think that a large company like Motorola, with many smart Engineers and massive resources at their disposal, would solve the problem.  Instead they rely on the end user to figure things out for themselves.


I'm not certain that the problem is as 'widespread' as it appears to be on forums.

New Visitor
k-why
Posts: 1
Registered: ‎04-17-2011

Re: Motorola SB6120 Cable Modem

Hi,

I've also had similar problems with my sb6120. Motorola told me that my upstream power level is too high. Mine ranged from 30dB to 57dB in about a 5 min time span. I called CC per motorola rec'd to request adjusting the power level to mid 40s. CC said they could not do this remotely, and needed someone to the house. Do you agree with this suggestion? Or should I try an attenuator?
Connection Expert
EG
Posts: 42,116
Registered: ‎12-24-2003

Re: Motorola SB6120 Cable Modem

[ Edited ]

 


 

k-why wrote:
Hi,

CC said they could not do this remotely, and needed someone to the house. Do you agree with this suggestion? Or should I try an attenuator?

 


 

Yes agreed. An "attenuator" won't do anything productive in this case. The transmit power should not be making such wide swings ! And if a premises tech that comes to your home and can't find a problem then they need to refer the problem to a maintenance/line tech. This is their S.O.P. 

Contributor
DarrenLloyd
Posts: 5
Registered: ‎04-18-2011

Re: Motorola SB6120 Cable Modem

[ Edited ]

Yes, huge problems!

 

I upgraded my (owned) SB5101 to an SB6120 a few weeks ago and have had constant problems ever since - ranging from bad performance/timeouts on connections to the modem spontaniously going down completely and restarting itself.

 

By the way, the modem will go down completely and restart about six times per day.

 

Numerous calls to Comcast have not resolved the issue. Highly frustrating, and there does not seem to be a way to escalate this problem, so now I'm seem to be stuck with it too...

Connection Expert
JamesR
Posts: 6,423
Registered: ‎09-29-2007

Re: Motorola SB6120 Cable Modem

If you are tenting the modem from Comcast, pack it upand take it back to the comcast store/payment center and swap it out.

If you bought it, then either take it back to the store you bought it from or contact Motorola.

 

Contributor
Posts: 5
Registered: ‎01-15-2009

Re: Motorola SB6120 Cable Modem

I called Comcast and asked about my connection issues.  Apparently the sb6120 is a good modem, mine was connecting correctly, but there are some issues with upstream voltages, so they're sending someone out to check the incoming lines tomorrow.  I'll post back with a complete list of symptoms and whether or not the fix corrected the problem when I get everything done.

 

One side note: these issues may have been going on for some time, but my old modem (a DOCSIS 1.0, I think) didn't mind the variances.  The newer DOCSIS 3.0 modems are apparently quite persnickety about the incoming connections, so if you're seeing these kinds of issues (intermittent packet drops, etc) after you upgrade to the sb6120 it may be indicative of an incoming link problem, not a modem problem.

Regular Contributor
heavytwenty
Posts: 28
Registered: ‎03-20-2011

Re: Motorola SB6120 Cable Modem

 


temujin2000 wrote:

I called Comcast and asked about my connection issues.  Apparently the sb6120 is a good modem, mine was connecting correctly, but there are some issues with upstream voltages, so they're sending someone out to check the incoming lines tomorrow.  I'll post back with a complete list of symptoms and whether or not the fix corrected the problem when I get everything done.

 

One side note: these issues may have been going on for some time, but my old modem (a DOCSIS 1.0, I think) didn't mind the variances.  The newer DOCSIS 3.0 modems are apparently quite persnickety about the incoming connections, so if you're seeing these kinds of issues (intermittent packet drops, etc) after you upgrade to the sb6120 it may be indicative of an incoming link problem, not a modem problem.


Could an upstream issue become worse through congestion? My connection has issues 24/7, but it becomes much worse around 7pm-midnight. Field techs found nothing, maintenance said they changed out 2 things but connection hasn't improved. I'm a new subscriber, so I only have a 6120; I don't have a D2 modem to test against it.

 

Contributor
Posts: 5
Registered: ‎01-15-2009

Re: Motorola SB6120 Cable Modem

I suppose it's entirely possible that congestion could cause upstream issues, but I would think congestion would cause upstream and downstream issues.  Have you had a tech take a look at your modem logs online?

Contributor
DarrenLloyd
Posts: 5
Registered: ‎04-18-2011

Re: Motorola SB6120 Cable Modem

Well, it's great to have all of these different theories about the SB6120 (signal strength, firmware, etc.), but I'm a paying customer who is no longer recieving the service that I'm paying for.

 

When will Comcast fix this issue??

 

It is ridicoulous that I purchase a modem which is recommended by Comcast, and then receive such appauling service. 

Networking Expert
Baric
Posts: 24,238
Registered: ‎07-28-2003

Re: Motorola SB6120 Cable Modem

Point your browser at http://192.168.100.1 and post your signal levels and log.  That might tell us what the issue is.

Contributor
DarrenLloyd
Posts: 5
Registered: ‎04-18-2011

Re: Motorola SB6120 Cable Modem

 

 

Model Name: SB6120
Vendor Name: Motorola
Firmware Name: SB612X-1.0.3.3-SCM00-NOSH
Boot Version: PSPU-Boot 1.0.0.4m1
Hardware Version: 3.0
Serial Number: 317001104500338207040011
Firmware Build Time: Aug 12 2010 13:58:19

 

Model Name: SB6120Vendor Name: MotorolaFirmware Name: SB612X-1.0.3.3-SCM00-NOSHBoot Version: PSPU-Boot 1.0.0.4m1Hardware Version: 3.0Serial Number: 317001104500338207040011Firmware Build Time: Aug 12 2010 13:58:19

 

 

Downstream Bonding Channel Value

Channel ID 1  2  3  

Frequency 717000000 Hz  723000000 Hz  729000000 Hz  735000000 Hz 

Signal to Noise Ratio 37 dB  37 dB  37 dB  37 dB 

Downstream Modulation QAM256  QAM256  QAM256  QAM256 

Power Level

The Downstream Power Level reading is a snapshot taken at the time this page was requested. Please Reload/Refresh this Page for a new reading

11 dBmV   12 dBmV   12 dBmV   12 dBmV  

Upstream Bonding Channel Value

Channel ID 8  7  

Frequency 30600000 Hz  25300000 Hz  37000000 Hz 

Ranging Service ID 2061  2061  2061 

Symbol Rate 5.120 Msym/sec  2.560 Msym/sec  5.120 Msym/sec 

Power Level 45 dBmV  44 dBmV  46 dBmV 

Upstream Modulation [3] QPSK

[3] 64QAM

  [3] QPSK

[2] 16QAM

  [3] QPSK

[3] 64QAM

 

Ranging Status Success  Success  Success 

Signal Stats (Codewords) Bonding Channel Value

Channel ID 1  2  3  

Total Unerrored Codewords 396914824  396915442  396915058  396914565 

Total Correctable Codewords 14 21 22 46 

Total Uncorrectable Codewords 1502 602 1515 1634 

 


 

 

Connection Expert
EG
Posts: 42,116
Registered: ‎12-24-2003

Re: Motorola SB6120 Cable Modem

[ Edited ]

@ DarrenLloyd. Did you happen to see this post that I made earlier in this thread ?

 

http://forums.comcast.com/t5/Connectivity-and-Modem-Help/Motorola-SB6120-Cable-Modem/m-p/916587#M131...

 

I have found that the downstream power level needs to be below +10dB for some of the 6120's

 

Do you have any extra coax cable splitters lying around that you could add in to the line leading to the modem ? It's worth trying. It worked for me ! I could reproduce this problem at will with mine. BTW you do indeed have the latest version of firmware which also fixed some of the spontaneous re-booting problems so it could be that the downstream power is too hot.

Regular Problem Solver
Posts: 790
Registered: ‎03-14-2005

Re: Motorola SB6120 Cable Modem

 


EG wrote: 

I have found that the downstream power level needs to be below +10dB for some of the 6120's

 


Wow! That pretty much rules out any thought of a Morotola SB6120 for me. My downstream level generally fluctuates right around +10dBmV (gets higher in cold weather), and adding an attenuator or splitter is out of the question because my upstream power level is already at +51dBmV. I sure hope my venerable SB5100 doesn't become unusable any time soon.

 

Bronze Problem Solver
Paraniod
Posts: 1,596
Registered: ‎06-15-2009

Re: Motorola SB6120 Cable Modem

[ Edited ]

 


MelvinTheGrate wrote:

 


 Wow! That pretty much rules out any thought of a Morotola SB6120 for me. My downstream level generally fluctuates right around +10dBmV (gets higher in cold weather), and adding an attenuator or splitter is out of the question because my upstream power level is already at +51dBmV. I sure hope my venerable SB5100 doesn't become unusable any time soon.

 


Just a thought, if you were thinking about buying your own. You could rent one from them for a month or two, get them to sort out any issues, then replace it with your own shiny new modem. :smileywink:

 

Connection Expert
EG
Posts: 42,116
Registered: ‎12-24-2003

Re: Motorola SB6120 Cable Modem


MelvinTheGrate wrote:

 


EG wrote: 

I have found that the downstream power level needs to be below +10dB for some of the 6120's

 


Wow! That pretty much rules out any thought of a Morotola SB6120 for me. My downstream level generally fluctuates right around +10dBmV (gets higher in cold weather), and adding an attenuator or splitter is out of the question because my upstream power level is already at +51dBmV. I sure hope my venerable SB5100 doesn't become unusable any time soon.

 


I  hear you Melvin but to my knowledge it is not with all 6120's across the board and neither is it in all areas. It seems to be only with certain brands of CMTS's. And yes, additional attenuation would be out of the question in your case. Perhaps you should have a tech out to properly balance your line to give you more wiggle room. There may be a return amp that needs readjusting and or an AGC circuit issue with it. BTW, that would need to be a maintenance tech but only a premise tech could make that escalation.

Connection Expert
EG
Posts: 42,116
Registered: ‎12-24-2003

Re: Motorola SB6120 Cable Modem

[ Edited ]

Paraniod wrote:

 

Just a thought, if you were thinking about buying your own. You could rent one from them for a month or two, get them to sort out any issues, then replace it with your own shiny new modem. :smileywink:

 


They may only "rent" a 6120 to someone that actually subscribes to one of their D3 speed tiers. YMMV.

Regular Problem Solver
Posts: 790
Registered: ‎03-14-2005

Re: Motorola SB6120 Cable Modem

[ Edited ]

 


EG wrote:

Perhaps you should have a tech out to properly balance your line to give you more wiggle room.

 

Problem is that (a) my levels aren't actually out of spec, through they are right at the edge of "acceptable", and (b) my current SB5100 is rock solid with these signal levels, so I can't claim to be having a service problem. Seems that I would most likely end up paying for a service tech visit and be told that my signal levels are satisfactory and my service is operating properly.

 

I don't have any plans for a higher tier than my current 12/2, so there's not much point in fighting that battle till my current modem goes EOL (for real, not like the recent error in the model list).

Contributor
DarrenLloyd
Posts: 5
Registered: ‎04-18-2011

Re: Motorola SB6120 Cable Modem

Thanks for the suggestion. So should I try an inline 3dB coaxial attenuator?

 

(The modem is the only cable device, so I don't have any splitters, etc.).

 

 

New Visitor
antarlin
Posts: 2
Registered: ‎04-18-2011

Re: Motorola SB6120 Cable Modem

Hi everyone, I've been having issues with my two months old SB6120 resetting itself continously as well. It worked for just about 50 days without an issue. Then one day I unplugged it because I was going to be away for two weeks. When I came back and tried to restart the cable modem, it failed to work and continously resets itself.

 

I have contacted Comcast Tech Support(s) and they all said my modem is defective and needs to be replaced. I have also emailed Motorola tech support but have not gotten any answer so far. I'm leaning toward that the modem is not defective and there may be a configuration issue with Comcast. I don't want to go through getting a replacement SB6120 and run into the same problem again.

 

From what I've read so far, my downstream power level may be too high, My downstream power levels are 13-14dBmV. I'll try getting a splitter when I get home and see if that will help with the issue. EG, where did you find the downstream dBmV specs for the SB6120? thanks for your help in advance.

 

Below are what I could get out of the modem before it resets itself.

 

In the log page these three lines keeps repeating in self:

SYNC Timing Synchornization failure

Received Response to Brocast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out

Cable Modem Reboot due to T4 Timeout

 

In the signal page of the SB6120 

 

Downstream

Channel ID 1 2 3 4

Frequency 681000000 Hz 687000000Hz 693000000Hz 699000000Hz

Signal to Noise Ratio 37 dB 37 dB 37dB 37 dB

Downstream Modulation QAM256 QAM256 QAM256 QAM256

Power Level 13 dBmV 14 dBmV 13 dBmV 13 dBmV

 

Upstream

Channel ID 1

Frequency 36400000 Hz

Ranging Service ID 5121

Symbol Rate 5.120 Msym/sec

Power Level 36 dBmV

Upstream Modulation [3] QPSK [3] 64QAM

Ranging Status T4 TimeOut

 

Additional information:

Model Name: SB6120

Vendor Name: Motorola

Firmware Name: SB612X-1.0.3.3-SCM00-NOSH

Boot Version: PSPU-Boot 1.0.0.4m1

Hardware Version: 3.0

Serial Number: 317001028601551205040011

Firmware Build Time: Aug 12 2010 13:58:19

 

Thanks in advance for any advices to troubleshoot this problem!

 

Connection Expert
EG
Posts: 42,116
Registered: ‎12-24-2003

Re: Motorola SB6120 Cable Modem

[ Edited ]

@ DarrenLloyd. Yes.

 

@ antarlin. Downstream power is too high. You can try using a 6dB attenuator such as one of these;

 

http://www.amazon.com/6db-Attenuator-Pad-1-each/dp/B0013L48XA/ref=pd_bxgy_e_text_b

 

Remember, I make no guarantees. All I know is that this works for many of these 6120's. 

New Visitor
antarlin
Posts: 2
Registered: ‎04-18-2011

Re: Motorola SB6120 Cable Modem

To rule out the possibility of a defective modem, I ended up returning my SB6120 and getting a new SB6120. Now my internet is working again. Not sure what caused the problem of my SB6120 resetting itself continously, but a new modem works. The new modems downstream power level shows lower then before (forgot the exact numbers, I'll post it when I get home) and I have not added any attenuators to the line. So I guess it was purely a defective modem. Weird. 

Connection Expert
JamesR
Posts: 6,423
Registered: ‎09-29-2007

Re: Motorola SB6120 Cable Modem

Thanks for providing the feedback.

New Visitor
Posts: 4
Registered: ‎03-03-2010

Re: Motorola SB6120 Cable Modem

Thanks for the link to the 6db Attenuator - might have to try that to see if it helps resolve connection issues

 

I too have experienced recent issues with SB6120 - the modem doesn't reboot, but loses internet connection [randomly happens whenever it starts raining].  I'm thinking a call to tech support to look at the lines to the house may be in order as the same issue happened with a DLINK cable modem.

Connection Expert
EG
Posts: 42,116
Registered: ‎12-24-2003

Re: Motorola SB6120 Cable Modem

@ koloumb. That isn't automatically a  blanket fix for everyone. In your case it could make things worse. We'd need to see your stats to advise. Your receive power may already be too weak... This mainly is intended for spontaneous modem re-booting issues with the 6120 due to excessive "receive" power.

Contributor
DarrenLloyd
Posts: 5
Registered: ‎04-18-2011

Re: Motorola SB6120 Cable Modem

The attenuator made no apparent difference. I installed it yesterday afternoon and the modem has gone down several times since installing it.

New Visitor
Posts: 4
Registered: ‎03-03-2010

Re: Motorola SB6120 Cable Modem

Downstream Bonding Channel Value

 

Channel ID 201 202 203 204 

Frequency 567000000 Hz 573000000 Hz 579000000 Hz 585000000 Hz 

Signal to Noise Ratio 36 dB 37 dB 37 dB 37 dB 

Downstream Modulation QAM256 QAM256 QAM256 QAM256 

Power Level -2 dBmV   0 dBmV   0 dBmV   0 dBmV  

 

Upstream Bonding Channel Value

Channel ID

Frequency 37400000 Hz 

Ranging Service ID 5816 

Symbol Rate 2.560 Msym/sec 

Power Level 41 dBmV 

Upstream Modulation [3] QPSK [2] 16QAM

Ranging Status Success 

 

Model Name: SB6120

Vendor Name: Motorola

Firmware Name: SB612X-1.0.3.3-SCM00-NOSH

Boot Version: PSPU-Boot 1.0.0.4m1

Hardware Version: 3.0

Firmware Build Time: Aug 12 2010 13:58:19

 

 

Log - [this happened while I was away out of town. Couldn't connect to Comcast for 4 hours - issue "mysteriously" fixed itself the next day]

 

TIME: Apr 25 2011 21:52:47

PRIORITY: 3-Critical

CODE: T05.0

MESSAGE: SYNC Timing Synchronization failure - Loss of Sync;CM-QOS=1.1;CM-VER=3.0;

 

Connection Expert
EG
Posts: 42,116
Registered: ‎12-24-2003

Re: Motorola SB6120 Cable Modem

[ Edited ]

@koloumb. Modem stats are fine. Don't use an attenuator. You also have the latest firmware version. Something else is going on in your case.

Connection Expert
EG
Posts: 42,116
Registered: ‎12-24-2003

Re: Motorola SB6120 Cable Modem

@DarrenLloyd. Sorry to hear that that didn't work out for you.

Visitor
Posts: 4
Registered: ‎12-05-2006

Re: Motorola SB6120 Cable Modem

I've been using my SB6120 for just over 2 months now.  Easy setup, family is gaming, streaming youtube, hulu, rhapsody, and/or netflix almost daily.  We download games, patches, dlc on PCs (mainly using Valve Software's Steam digital distribution store), as well as stuff for the Playstation 3 (although the PSN been down for a couple weeks now), often while simultaneously streaming video or music.  My network regularly consists of 3 desktop gaming PCs, 1 media PC, 2 laptops, a wireless Epson printer, and a wireless PS3, with various 'guest' laptops and wi-fi phones from friends and family at any given time.

 

Am I to understand my modem's upstream power level of 56 dBmV is far too high?  My old rented SB5100 apparently had 'too high' an upstream power level as well...for the 4 years I was foolish enough to pay the monthly rental fee. 

Connection Expert
EG
Posts: 42,116
Registered: ‎12-24-2003

Re: Motorola SB6120 Cable Modem

[ Edited ]

If both the old and the new modem have high transmit power it not likely to be a modem malfunction. It is more likely to be a line quality issue as in too much attenuation. What does the receive power figure look like ? I'm surprised that the modem isn't already rebooting spontaneously. If you're not having any problems right now, you are very close as there isn't much wiggle room to allow for normal fluctuations. The 6120 is less forgiving of this than the 5100 is/was. Are there any excess/unneeded splitters in the line leading directly to the modem that can be eliminated/re-configured ?

New Visitor
MrKid
Posts: 4
Registered: ‎05-15-2011

Re: Motorola SB6120 Cable Modem

[ Edited ]

Hello, EG. I just got my new 6120 today, I just want to post my modem information and see if my power level is normal.

 

Downstream Bonding Channel ValueChannel ID 1  2  3  4  Frequency 717000000 Hz  723000000 Hz  729000000 Hz  735000000 Hz  Signal to Noise Ratio 38 dB  38 dB  38 dB  38 dB  Downstream Modulation QAM256  QAM256  QAM256  QAM256  Power Level The Downstream Power Level reading is a snapshot taken at the time this page was requested. Please Reload/Refresh this Page for a new reading 10 dBmV   10 dBmV   10 dBmV   10 dBmV  

Upstream Bonding Channel Value Channel ID 11  Frequency 30600000 Hz  Ranging Service ID 3565  Symbol Rate 5.120 Msym/sec  Power Level 37 dBmV  Upstream Modulation [3] QPSK
[3] 64QAM
  Ranging Status Success 

Signal Stats (Codewords) Bonding Channel ValueChannel ID 1  2  3  4  Total Unerrored Codewords

41554222  41554080  41553994  41554259  Total Correctable Codewords 18  0  0  0  Total Uncorrectable Codewords 652  570  523  515 

 

I can not feel any speed increase at all, same speed I got with my ubee D2 modem.



 

Connection Expert
EG
Posts: 42,116
Registered: ‎12-24-2003

Re: Motorola SB6120 Cable Modem

[ Edited ]

Your receive power is high and is borderline out of spec. Just because you now have this modem doesn't mean that your sustained speeds automatically will be higher. It will still always be governed by the config file sent to your modem for your subscribed speed tier. Your sustained speeds however should be delivered more consistently and reliably during the times of peak internet usage because of the increased capacity/bandwidth made available by the multiple downstream channel bonding (D3). Some users have reported that they do see higher initial "Powerboost" speed burst results with a D3 capable modem.

New Visitor
MrKid
Posts: 4
Registered: ‎05-15-2011

Re: Motorola SB6120 Cable Modem

Thanks for the quick reply. I was wondering if I just go back to use the D2 modems since they are almost half of the cost and give the same speed. But since from what you said, the speed will be more consistently and reliably, I am going to keep this one.

 

Do you suggest to modifiy my modem to decrease my recieve power?