Ken Walsh
@63.237.x.x
| Modem or Signal Strength
I’m having some problems with my Motorola Surfboard Modem SB4100, The modem keeps losing the signal. I called Comcast and a tech came (over an hour late) and tested the line throughout the house at every connection and told me that every thing in the house looks ok and a line tech will have to come check the poll. To my amazement a line tech did arrive the same day and said he boosted the single.
After all that I’m still continuing to lose single from Comcast. Comcast told me that it must be the modem, but I still think the signal is weak. After reading the FAQ on this site I checked the status of the modem and everything looked good but the downstream power level was at -19 dBmV. I believe it should be in the range of +3 and –5 dBmv according to the FAQ.
Can someone please help me and let me know if my problem is the modem or the Signal. This is the single data from the modem.
Downstream
Signal to Noise Ratio 31 dB
QAM 64
Power Level -19 dBmV
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
Upstream
Frequency 35600000 Hz Ranged
Ranging Service ID 275
Symbol Rate 2.560 Msym/s
Power Level 51 dBmV
Thanks!!!
Ken |
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JTRockville
Data Ho
Premium,MVM
join:2002-01-28
Rockville, MD
clubs:
 ·LINGO
 ·Sprint Mobile Broa..
 ·surpasshosting
 ·Verizon FIOS
| said by Ken Walsh:
After reading the FAQ on this site I checked the status of the modem and everything looked good but the downstream power level was at -19 dBmV. I believe it should be in the range of +3 and –5 dBmv according to the FAQ.
Downstream powerlevel should be between -15 dBmV and +15 dBmV. But either way, yours is out of spec. Even more important: your modem keeps losing sync!!
There may be more clues in your logs. Can we get a peek?
»192.168.100.1/logs.html
Any splitters on the coax between where the cable comes to the house and your modem? |
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walsh44
join:2003-05-29
Attleboro, MA
| Yes, there are two splitters in the line before the cable modem. It has been that way since Roadrunner was installed years ago. Attached is my log info.
Thanks |
|
JTRockville
Data Ho
Premium,MVM
join:2002-01-28
Rockville, MD
clubs:
·LINGO
·Sprint Mobile Broa..
·surpasshosting
·Verizon FIOS
| Welcome to the Comcast Forum
According to the timestamp in your logs, your modem became operational at 6pm tonight? Hmmm...
You're having trouble acquiring an upstream signal. When you got sync, your upstream powerlevel was 54. When you posted your signals, it was 51. What is it now?
I've never even seen that "RR Abort" error before, but it can't be good. said by walsh44  modem event logs:
030529181559 7-Information I503.0 Cable Modem is OPERATIONAL
030529181559 7-Information F502.1 Bridge Forwarding Enabled.
030529181559 7-Information F502.3 Bridge Learning Enabled.
030529181559 7-Information B0.0 Baseline Privacy
030529181558 7-Information I500.0 Registration Completed
030529181558 7-Information I0.0 REG-RSP Registration Response
030529181558 7-Information I0.0 REG-REQ Registration Request
030529181558 7-Information D509.0 Retrieved TFTP Config File SUCCESS
030529181558 7-Information D507.0 Retrieved Time....... SUCCESS
************ 7-Information D511.0 Retrieved DHCP .......... SUCCESS
************ 5-Warning D520.2 DHCP Attempt# 1 BkOff: 5s Tot DSC:1 OFF:1 REQ:1 ACK:1
************ 7-Information D0.0 DHCP CM Net Configuration download and Time of Day
************ 7-Information T500.0 Acquired Upstream .......... SUCCESS
************ 8-Debug T503.1 Acquire US with status OK, powerLevel 54, tempSid 275
************ 8-Debug T505.0 Acquired Upstream with status OK
************ 7-Information T501.0 Acquired Downstream (693000000 Hz)........SUCCESS
************ 8-Debug T509.0 Acquired DS with status OK, DS Freq 693000000, US Id 2
************ 8-Debug T509.0 Acquired DS with status NO FEC lock, DS Freq 121756000, US Id 0
(hunt snipped)
************ 8-Debug T509.0 Acquired DS with status NO FEC lock, DS Freq 115755700, US Id 0
************ 7-Information H501.2 HFC: Shutting Downstream Down
************ 7-Information H501.1 HFC: Shutting Upstream Down
************ 8-Debug T503.1 Acquire US with status RR ABORT, powerLevel 0, tempSid 0
************ 7-Information T501.0 Acquired Downstream (693000000 Hz)........SUCCESS
************ 8-Debug T509.0 Acquired DS with status OK, DS Freq 693000000, US Id 2
************ 8-Debug T509.0 Acquired DS with status NO FEC lock, DS Freq 109755400, US Id 0
(hunt snipped)
************ 8-Debug T509.0 Acquired DS with status NO FEC lock, DS Freq 499774900, US Id 0
************ 7-Information H501.2 HFC: Shutting Downstream Down
************ 7-Information H501.1 HFC: Shutting Upstream Down
************ 8-Debug T503.1 Acquire US with status RR ABORT, powerLevel 0, tempSid 0
************ 7-Information T501.0 Acquired Downstream (693000000 Hz)........SUCCESS
************ 8-Debug T509.0 Acquired DS with status OK DS Freq 693000000, US Id 2
************ 8-Debug T509.0 Acquired DS with status NO FEC lock, DS Freq 123000000, US Id 0
(hunt snipped)
Event Log has reached maximum size. Older log entries are lost.
|
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walsh44
join:2003-05-29
Attleboro, MA |  My current upstream power level is 45. |
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JTRockville
Data Ho
Premium,MVM
join:2002-01-28
Rockville, MD
clubs: | Somehow, I think it's NOT the modem. That's wacky upstream signal behavior. Generally, signals will vary a bit but not like that.
Do you own or rent?
Did your downstream powerlevel or SNR change at all? |
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jimjar
Premium
join:2002-05-20
Tucson, AZ
| reply to Ken Walsh
45 is great. You should generally worry about upstream that is 55 or greater. 58 is as bad as it gets, this is the top power output of the modem.
I live in Tucson and it is hot. My upstream power increases about 4db each day in the summer as the outside temp goes up from about 75 to 105. (hotter is worse). I have never seen a daily variation of 10. Is something going on outside ?? A big rainstorm maybe ?
BTW - welcome to DSL reports ! |
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jimjar
Premium
join:2002-05-20
Tucson, AZ
| reply to Ken Walsh
and of course, the -19db downstream stinks. I am very surprised that the Comcast tech didn't do anything about that, maybe run another line. Even eliminating the 2 splitters will get you 7db at best which would get downstream to -12 which is okay but not great. |
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Rhobite
Premium
join:2002-02-24
Cambridge, MA
clubs: | reply to Ken Walsh
JT- the modem's time is usually in UTC, at least mine (SB4200) is. So it would be a few hours ahead of the actual local time. I guess it just depends on the time at the CMTS. Anyway my modem's time is way off. |
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walsh44
join:2003-05-29
Attleboro, MA
| Thank to all for your information!!!
To answer JTRockville, I own the modem and the downstream powerlevel has not changed, every time I check it is -19.
I’m going to give Comcast a call and schedule another appointment. I will let you know how I make out.
Thanks Again!!! |
|
jacour
join:2001-12-11
Ypsilanti, MI
 ·Comcast
| reply to Rhobite
I had a similar problem a few months back with timeouts. After several truck rolls where the techs swapped my modems, one fellow called in the line techs to get up on the pole and tweak the signal strength. Once the signal was back in spec, the modem was much happier and my trouble went away. I just checked the log and the last timeout was in March.
Just keep calling until they send you one of the better techs who will figure out what the problem is. The line tech should not have left with a -19db signal. |
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walsh44
join:2003-05-29
Attleboro, MA
| I called Comcast and scheduled an appointment for Sunday for 11-1, and yes the tech was late again and arrived at 2:45. The tech did all the same tests and said that there will be a line tech sometime on Monday. The funny thing is on Sunday night the modem lost the signal again and when it re-synced my downstream power level improved to –13 and has been steady and has not lost signal.
Thanks again for the help! |
|
Qumahlin
Never Enough Time
Premium,MVM
join:2001-10-05
united state
| reply to JTRockville
said by JTRockville :
Welcome to the Comcast Forum
According to the timestamp in your logs, your modem became operational at 6pm tonight? Hmmm...
You're having trouble acquiring an upstream signal. When you got sync, your upstream powerlevel was 54. When you posted your signals, it was 51. What is it now?
I've never even seen that "RR Abort" error before, but it can't be good.
When a modem is trying to lock onto upstream what it does is it keeps increasing it's power level one by one until it achieves lock. This is why if you goto the modems signal page as it is booting and keep hitting refresh you will see the upstream power level rise.
RR abort occurs when the modem is trying to boot and it reaches 58db without acheiving lock. It can't go any higher so it aborts its search and drops the US back to 0 to start again
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Forum Posts:2800 |
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walsh44
join:2003-05-29
Attleboro, MA | Would an amplifier help me with my downstream power level? It is ranging from –13 to –19, depending on the time of the day. |
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briankelly9
Premium
join:2002-09-11
| I think amping that up wouldnt do anything. Your -19 for a reason somethings wrong somewhere. Are they 2 way splitters or a 3 way to a 4 way or something ? try figuring a way to have it just go thru one splitter just for a night and then do all your tests and see the difference. do you have rg6 cable to the modem or rg59 cable ?
--
»briankellycable.com |
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cablejoe
join:2002-01-15
Las Vegas, NV
| reply to Ken Walsh
How do your TV's look, particularly on the higher channels? You might want to check these when you check the cable modem, and see if you notice a difference in picture quality when the modem is reporting lower signal levels.
Also, keep in mind: the SurfBoards will only report signal levels in the range of -19/+19 dBmV...so your signal level could actually be considerably lower than -19, but the modem won't go any lower. (It will report -19 dBmV even if the cable is unplugged.)
If possible, plug your modem in at another cable outlet, and see if it still reports similar levels.
It's possible (however unlikely) that the F connector in the modem is going bad; the modem simply reports the levels that it sees, and if the port is going bad, then it's not going to get accurate readings. But as I mentioned, this is pretty unlikely....just another possibility. |
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CableUZR
Cuidado, Hay Llamas
join:2003-02-04
Mount Holly, NJ
clubs:
| reply to Ken Walsh
IF you have a laptop or have a friend that does, try to connect your modem to the very first line that comes to the house, then see what the status page reports. (Usually there's a grounding block that is on the side of the house, it looks like a two-sided connector with coax coming in one side and going out the other.) |
|
Gaddor
join:2002-11-02
Mays Landing, NJ
| reply to Ken Walsh
I had similar problems with my SB4100 about 6 months ago..
I was getting lots of latency, the modem light would still be locked but I couldn't do anything, ping, web ect.. Then it would magically clean up all the sudden..
A few times I lost signal lock for 5min to 1hour.. (figured it was them till I started checking with friends close by)
Anyway... at that time my downstream power level was pegged at -11 dBmV (which is within spec), but Im not sure if maybe it randomly got worse..
This is in a new house that had a 4 way splitter on the side of the house, 1 line direct to each room, including the modem..
To make a long story short.. I took out the 4 way splitter (Since I use DirecTV satellite, I only keep basic cable for the mini discount).. Put a barrel connector from the comcast side to the line directly to the modem..
My downstream power level went to -2dBmv and havent had a problem (from my side) ever sense..
If you have a direct line to your cable modem, pick up a Female to Female barrel connecter from Radio Shack, and connect the Comcast feed line directly to your modem and see if your signals improve..
Here is the dump I got from my SB4100
------
Frequency 723000000 Hz Locked
Signal to Noise Ratio 37 dB
QAM 64
Network Access Control Object ON
Power Level -2 dBmV 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
Upstream Value
Channel ID 6
Frequency 21584000 Hz Ranged
Ranging Service ID 983
Symbol Rate 2.560 Msym/s
Power Level 47 dBmV |
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