Rookie

Cannot get close to 400 MBPS with CM600 with in-spec Signal levels (Near Downtown LA)

Before Spectrum bought out TWC, I had the 200/20 package using my own modem (An approved TP-Link modem). I consistently got 250 down/22 up during any test at any time of day. 

 

Now that I’ve “upgrade “ to Spectrum’s 400/20 package again using my own Netgear CM600 router, after several tech visits I’ve averaged 100-170 down / 22 up with near-perfect signal levels (posted below). My logs show an occasional T3 timeout about once every two weeks but are otherwise empty. 

 

Spectrum phone support has suggested that I use their own in-house modem but I don’t see how that should make any difference whatsoever. I’ve asked phone support to look at my modem config files to no avail and I’m at a loss.  I’m near Downtown LA any help/guidance would be appreciated. 

 


Startup Procedure

ProcedureStatusComment
Acquire Downstream Channel567000000 HzLocked
Connectivity StateOKOperational
Boot StateOKOperational
SecurityEnableBPI+
IP Provisioning ModeOverride MDDIPv6 only
 

<tabindex=-1>Downstream Bonded Channels

ChannelLock StatusModulationChannel IDFrequencyPowerSNRCorrectablesUncorrectables
1LockedQAM2562567000000 Hz4.5 dBmV41.0 dB00
2LockedQAM2563573000000 Hz4.9 dBmV41.2 dB00
3LockedQAM25615645000000 Hz5.3 dBmV41.1 dB00
4LockedQAM25610615000000 Hz5.4 dBmV41.2 dB00
5LockedQAM25612627000000 Hz5.6 dBmV41.2 dB00
6LockedQAM2567597000000 Hz5.4 dBmV41.3 dB00
7LockedQAM25613633000000 Hz5.4 dBmV41.0 dB00
8LockedQAM25614639000000 Hz5.3 dBmV40.9 dB00
9LockedQAM25617657000000 Hz5.2 dBmV40.8 dB00
10LockedQAM25618663000000 Hz5.2 dBmV40.8 dB00
11LockedQAM25619669000000 Hz4.7 dBmV40.5 dB00
12LockedQAM25620675000000 Hz4.7 dBmV40.1 dB00
13LockedQAM25621681000000 Hz4.4 dBmV40.2 dB00
14LockedQAM25622687000000 Hz4.3 dBmV40.2 dB00
15LockedQAM25623693000000 Hz4.2 dBmV40.2 dB00
16LockedQAM25624699000000 Hz4.0 dBmV40.2 dB00
17LockedQAM25625705000000 Hz3.7 dBmV40.9 dB00
18LockedQAM25626723000000 Hz2.4 dBmV40.4 dB00
19LockedQAM25627729000000 Hz2.0 dBmV40.3 dB00
20LockedQAM25628735000000 Hz1.3 dBmV39.9 dB00
21LockedQAM25629741000000 Hz0.8 dBmV39.5 dB00
22LockedQAM25630747000000 Hz0.3 dBmV39.4 dB00
23LockedQAM25616651000000 Hz5.4 dBmV42.3 dB00
24LockedQAM25632759000000 Hz0.1 dBmV38.9 dB00
 

<tabindex=-1>Upstream Bonded Channels

ChannelLock StatusUS Channel TypeChannel IDSymbol RateFrequencyPower
1LockedATDMA815120 Ksym/sec17800000 Hz44.3 dBmV
2LockedATDMA825120 Ksym/sec24200000 Hz44.0 dBmV
3LockedATDMA835120 Ksym/sec30600000 Hz44.5 dBmV
4LockedATDMA845120 Ksym/sec37000000 Hz45.0 dBmV
5Not LockedUnknown00 Ksym/sec0 Hz0.0 dBmV
6Not LockedUnknown00 Ksym/sec0 Hz0.0 dBmV
7Not LockedUnknown00 Ksym/sec0 Hz0.0 dBmV
8Not LockedUnknown00 Ksym/sec0 Hz0.0 dBmV
6 REPLIES
Helper

Re: Cannot get close to 400 MBPS with CM600 with in-spec Signal levels (Near Downtown LA)

I would use the Spectrum modem temporarily just to troubleshoot. If nothing else, it will definitely tell you (and Spectrum) if the problem lies with your customer owned equipment or the something else. As long as you are using your own modem it will be blamed absent any other data.

 

Browser

Re: Cannot get close to 400 MBPS with CM600 with in-spec Signal levels (Near Downtown LA)

well said reds91185
Proven Sharer

Re: Cannot get close to 400 MBPS with CM600 with in-spec Signal levels (Near Downtown LA)

YOU may happen to think those incoming DS signal levels are in-spec; in fact they point to a serious cable system maintenance problem.  Notice how your modem reports all of the lower data channels (below 705 MHz) as receiving signals in the +4.5 to +5.6 dBmV range, but above 723 MHz the level starts dropping off from +2.4 down to only +0.1 dBmV??  That is definitely NG!!  The difference in received signal level between the very weakest and very strongest should be no more than 3 dB.  And you are correct that using a different modem (theirs) is NOT going to fix your data speed issue.

 

Here's why:  I'd guess that Spectrum 'recently' added their DS channels 25 thru 32 in your area after clearing off a bunch of basic analog channels.  Here in my area they uncovered and then had to sweep through the area and replace a bunch of older TWC-era line amplifiers and taps that were only built to run on channels up to 750 Mhz.  BTW, the same thing would happen if you had some old 2-port or 4-port splitters that are only marked for 750 MHz.  

 

But calling Spectrum to set up a home tech service visit probably will get your data moving reliably.  Print a copy of the signal level report so the tech can see what everyone here on the forums has already noticed.  Then s/he can get the line maintenance crew to reset the amplifier gain levels and update any ancient tap hardware.  It usually takes them about a week to get the bucket truck crews booked.  Please report back after the tech visit. 

Rookie

Re: Cannot get close to 400 MBPS with CM600 with in-spec Signal levels (Near Downtown LA)

Thank you for your very insightful message!  As you have pointed out, I tried using the Spectrum Modem today and have seen no difference whatsoever in my DS speeds (as expected).  Your insight to the huge disparities in the signal strengths was something I was unaware of and is something I will speak with the technicians about.   Will report after the visit.

Not applicable

Re: Cannot get close to 400 MBPS with CM600 with in-spec Signal levels (Near Downtown LA)

Which Spectrum modem did you try? A TM1602 or a DOCSIS 3.1 unit?

Rookie

Re: Cannot get close to 400 MBPS with CM600 with in-spec Signal levels (Near Downtown LA)

I had the maintenance crew come out per your recommendation and they reduced the signal strength on the lower band signals.  I am now comfortably getting 370-420 on my DS.  Thank you for your solution.