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spmurph
join:2013-03-21
Sewell, NJ

spmurph

Member

[Connectivity] Modem or Connection

Purchased Motorola SB 6141 modem a month ago and download speed has gotten progressively slower and is now less than 1Mbps. Uploads speeds have remained around 4 Mbps.

Called Comcast Saturday. They said signal was fine and set up an appt. for Monday. Line tech came out and said the line was good. Lead tech came out tonight plugged in laptop and said the same thing. He tried a bunch of different things and could get the d/l speeds back to 25 Mbps down but was unable to get the fixes to stay once he had to rebot the modem.

Here are the signal levels:

Downstream Power Levels: 12, 12, 12, 12, 12, 13, 14

Downstream Signal to Noise Ratio: 37, 37, 37, 37, 37, 38, 38, 38

Upstream Power Level: 36, 37, 37

--------------------------------------------------------------------------------

ShaperProbe results

DiffProbe release. January 2012. Build 1008.
Shaper Detection Module.

Connected to server 4.71.251.149.

Estimating capacity:
Upstream: 862 Kbps.
Downstream: 20091 Kbps.

The measurement will take upto 3.0 minutes. Please wait.

Checking for traffic shapers:

Upstream: No shaper detected.
Median received rate: 970 Kbps.

Downstream: Measurement aborted due to high packet loss rate.

For more information, visit: »www.cc.gatech.edu/~parth ··· iffprobe

Not sure if I should call Motorola and try to return the Modem under warranty or if I should get Comcast to have a tier 2 tech handle it.

owlyn
MVM
join:2004-06-05
Newtown, PA

1 recommendation

owlyn

MVM

Your DS levels are too high and your US Levels are low. Something is wrong but there's not enough info to tell what. Easiest thing to try at this point is exchange the modem.
spmurph
join:2013-03-21
Sewell, NJ

spmurph

Member

Thanks for the reply.

nerdburg
Premium Member
join:2009-08-20
Schuylkill Haven, PA

nerdburg to spmurph

Premium Member

to spmurph
Your signal is "hot" - the downstream in particular. That modem has a reputation for not tolerating high downstream levels. A 6dB attenuator probably would fix you up (»www.techtoolsupply.com/P ··· =FAM-6HR). You could probably stick a 3-way splitter in the line to temporarily address the issue.

A lead tech said those levels were fine? The Comcast phone reps said those levels were OK too?

With that said, is there a router involved?
spmurph
join:2013-03-21
Sewell, NJ

spmurph

Member

I purchased the attenuator you recommended.

Yes, both techs said there were no problems with the line signal. They screwed the cable into their handheld devices. Who knows what the hell the phone tech was looking at.

I do have a router. It is a Linksys E4200v2.

PeteC2
Got Mouse?
MVM
join:2002-01-20
Bristol, CT

PeteC2

MVM

That router shouldn't be an issue. I would be curious to see if a modem such as the Zoom 5341J, which is known to be a bit more forgiving of signal extremes might be more tolerant, and perform better. Also, you are at a slight disadvantage since it is not a Comcast-owned modem...they can say it is your modem's problem, whether correct or not.

Anyone else think this might be worth exploring?

I have at one time had signals in the -12db range with that tier (but rectified that), yet had no problems maintaining speed/stability, however, I would disagree with the tech's analysis that the signal was "fine".

Had you been able to get consistent performance with that signal, well then, ok, but obviously you are experiencing issues, in which case, I would not ignore the out of range signal.

SHoTTa35
@kfvaluation.com

SHoTTa35 to spmurph

Anon

to spmurph
Wait, did nobody else see this:

Downstream: Measurement aborted due to high packet loss rate.

We all like -10 to 10 but the fact is +/-15 is generally where the cut off is. 37 on the upstream isn't terrible also.

I agree though bumping the signals might help but if not definitely check out that packet loss which might be further down the line than just at your modem.
spmurph
join:2013-03-21
Sewell, NJ

spmurph

Member

Attenuator was in the mail when I came home. Hooked it up and here are the new levels:

downstream power: 6, 6, 6, 6, 6, 7, 7, 7

downstream SNR: 37. 37. 37, 37, 35, 39, 38, 37

upstream power: 42, 43, 42

Shaperprobe:

DiffProbe release. January 2012. Build 1008.
Shaper Detection Module.

Connected to server 38.102.0.111.

Estimating capacity:
Upstream: 793 Kbps.
Downstream: 20887 Kbps.

The measurement will take upto 3.0 minutes. Please wait.

Checking for traffic shapers:

Upstream: No shaper detected.
Median received rate: 933 Kbps.

Downstream: Measurement aborted due to high packet loss rate.

For more information, visit: »www.cc.gatech.edu/~parth ··· iffprobe

Download speeds are now around 6Mb (little better but not where is should be) and upload is still around 4Mb

Guess I should call Motorola and see what they say?
spmurph

spmurph to SHoTTa35

Member

to SHoTTa35
Attenuator was in the mail when I came home. Hooked it up and here are the new levels:

downstream power: 6, 6, 6, 6, 6, 7, 7, 7

downstream SNR: 37. 37. 37, 37, 35, 39, 38, 37

upstream power: 42, 43, 42

Shaperprobe:

DiffProbe release. January 2012. Build 1008.
Shaper Detection Module.

Connected to server 38.102.0.111.

Estimating capacity:
Upstream: 793 Kbps.
Downstream: 20887 Kbps.

The measurement will take upto 3.0 minutes. Please wait.

Checking for traffic shapers:

Upstream: No shaper detected.
Median received rate: 933 Kbps.

Downstream: Measurement aborted due to high packet loss rate.

For more information, visit: »www.cc.gatech.edu/~parth ··· iffprobe

Download speeds are now around 6Mb (little better but not where is should be) and upload is still around 4Mb

Guess I should call Motorola and see what they say?
spmurph

spmurph to SHoTTa35

Member

to SHoTTa35
Attenuator was in the mail when I came home. Hooked it up and here are the new levels:

downstream power: 6, 6, 6, 6, 6, 7, 7, 7

downstream SNR: 37. 37. 37, 37, 35, 39, 38, 37

upstream power: 42, 43, 42

Shaperprobe:

DiffProbe release. January 2012. Build 1008.
Shaper Detection Module.

Connected to server 38.102.0.111.

Estimating capacity:
Upstream: 793 Kbps.
Downstream: 20887 Kbps.

The measurement will take upto 3.0 minutes. Please wait.

Checking for traffic shapers:

Upstream: No shaper detected.
Median received rate: 933 Kbps.

Downstream: Measurement aborted due to high packet loss rate.

For more information, visit: »www.cc.gatech.edu/~parth ··· iffprobe

Download speeds are now around 6Mb (little better but not where is should be) and upload is still around 4Mb

Guess I should call Motorola and see what they say?
spmurph

spmurph

Member

Contacted Motorola last night and basically they said the problem was with the signal. They want me to insist that a tech come out and get the signal to optimal levels (he gave me the specs but I have them written down at home) before trying to use another modem.

Also, he was curious why Comcast is using all 8 channels for the download stream. He stated one channel can handle up to 40 GB which obviously would handle my needs.