CAX30 Poor Downstream Connection / Partial help

[dannydiggz]

I've had this CAX30 router/modem for about 10-11months. Pro installed by Cox (1gig)

I had issues with stability in the past, but it seemed fine for months and now all of a suden back to stability issues and slow download speeeds. Upload speeds are fine (Weird!)

I tried to downgrade the firmware in the past, but it automatically pushes it to the latest, so I have not done that this time.

I've tried a few factory resets & reboots but it seems to come back and goto the "Partial" mode w/30mbps download speeds shortly after.

Currently is Firmware Version V2.2.4.2

Let me know what you guys think is going on?

-DW

Cable Diagnostic
Startup Procedure
CM status: OPERATIONAL
DownstreamChannel: 807000000Hz Locked
ConnectivityState: OK operational(12),
BootState: OK Operational
Security: Enabled
IPProvisioningMode: 12 IPv4Only

Downstream Bonded Channels
Channel LockedStatus Modulation Channel ID Frequency Power SNR Correctables Uncorrectables
1 Locked 256 QAM 37 807000000 Hz -20.1 dBmV 30.3 dB 174222 0
2 Locked 256 QAM 1 117000000 Hz -4.6 dBmV 42.4 dB 0 0
3 Locked 256 QAM 2 123000000 Hz -2.0 dBmV 44.0 dB 0 0
4 Locked 256 QAM 3 129000000 Hz -3.5 dBmV 43.1 dB 0 0
5 Locked 256 QAM 4 135000000 Hz -4.1 dBmV 43.1 dB 0 0
6 Locked 256 QAM 5 141000000 Hz -3.3 dBmV 44.2 dB 0 0
7 Locked 256 QAM 6 147000000 Hz -5.3 dBmV 43.1 dB 0 0
8 Locked 256 QAM 7 153000000 Hz -6.6 dBmV 42.1 dB 0 0
9 Locked 256 QAM 21 237000000 Hz -4.8 dBmV 44.4 dB 0 0
10 Locked 256 QAM 25 735000000 Hz -16.6 dBmV 34.1 dB 0 0
11 Locked 256 QAM 26 741000000 Hz -17.0 dBmV 33.7 dB 3 0
12 Locked 256 QAM 27 747000000 Hz -17.0 dBmV 33.6 dB 3 0
13 Locked 256 QAM 28 753000000 Hz -17.5 dBmV 33.1 dB 8 0
14 Locked 256 QAM 29 759000000 Hz -17.3 dBmV 33.3 dB 11 0
15 Locked 256 QAM 30 765000000 Hz -17.0 dBmV 33.6 dB 2 0
16 Locked 256 QAM 31 771000000 Hz -17.0 dBmV 33.5 dB 2 0
17 Locked 256 QAM 32 777000000 Hz -17.5 dBmV 33.1 dB 252 0
18 Locked 256 QAM 33 783000000 Hz -18.3 dBmV 32.3 dB 8456 0
19 Locked 256 QAM 34 789000000 Hz -19.0 dBmV 31.4 dB 10362 0
20 Locked 256 QAM 35 795000000 Hz -19.0 dBmV 31.5 dB 56792 0
21 Locked 256 QAM 36 801000000 Hz -19.9 dBmV 30.5 dB 391345 1
22 Locked 256 QAM 38 813000000 Hz -20.2 dBmV 30.2 dB 444699 5
23 Locked 256 QAM 39 819000000 Hz -20.6 dBmV 29.7 dB 3028339 3890
24 Locked 256 QAM 40 825000000 Hz -20.8 dBmV 29.6 dB 5415171 26876
25 Locked 256 QAM 41 831000000 Hz -21.2 dBmV 29.1 dB 4813377 2888436
26 Locked 256 QAM 42 837000000 Hz -21.4 dBmV 28.9 dB 2955695 606993
27 Locked 256 QAM 43 843000000 Hz -22.1 dBmV 28.1 dB 9602604 1932112
28 Locked 256 QAM 44 849000000 Hz -23.9 dBmV 26.6 dB 7081084 4537984
29 Locked 256 QAM 45 855000000 Hz -23.9 dBmV 26.7 dB 7264224 5315656
30 Locked 256 QAM 46 861000000 Hz -24.8 dBmV 0.0 dB 19231 0
31 Locked 256 QAM 47 867000000 Hz -24.4 dBmV 26.3 dB 10222474 4235839
32 Locked 256 QAM 48 873000000 Hz -24.2 dBmV 0.0 dB 15521 0

Upstream Bonded Channels
Channel LockedStatus ChannelType Channel ID SymbolRate Frequency Power
1 Locked ATDMA 1 5120 Ksym/sec 17600000 Hz 45.5 dBmV
2 Locked ATDMA 2 5120 Ksym/sec 24000000 Hz 48.8 dBmV
3 Locked ATDMA 3 5120 Ksym/sec 30400000 Hz 49.3 dBmV
4 Locked ATDMA 4 5120 Ksym/sec 36800000 Hz 46.3 dBmV
5 Not Locked Unknown 0 0 Ksym/sec 0 Hz 0 dBmV
6 Not Locked Unknown 0 0 Ksym/sec 0 Hz 0 dBmV
7 Not Locked Unknown 0 0 Ksym/sec 0 Hz 0 dBmV
8 Not Locked Unknown 0 0 Ksym/sec 0 Hz 0 dBmV

Downstream OFDM Channels
Channel Channel ID Frequency Power SNR/MER ActiveSubcarrier Correctable Uncorrectable
1 159 300000000 Hz -5.9 dBmV 43.6 dB 296 ~ 7895 4092704 0
2 160 918000000 Hz -25.9 dBmV 0.0 dB 2216 ~ 5975 4092704 0

Upstream OFDMA Channels
Channel UpstreamMuted RangingStatus Subc Zero Freq ActiveSubcarrier SymbolsPerFrame Power
2 False Success 36.8 MHz 148 ~ 1907 12 42 dBmV
2 n/a Other 0 MHz 0 ~ 0 0 0 dBmV

[Kitsap · Accepted solution]

Just took a second look at your latest cable data.  It appears Cox has enabled mid-split in your area.  I can see your OFDM channel 2 is running at 918 MHz and the power level is way below specification.  There is a good chance Cox did that in the past year.

Whether you only use one connection or not, there could be a splitter in your coax connection.  Many old splitters are rated for 5-860 MHz and cause a significant signal loss above that frequency range.  The splitter needs to be replaced.

[Kitsap]

Most of the power levels on your downstream bonded channels are way out of specification (low).  For reference look at the first few sentences here: 

https://kb.netgear.com/24311/Power-level-guidelines-for-a-NETGEAR-cable-modem-router

Either the coax itself, the connectors, or a splitter between your CAX30 and the ISP have major issues.

Usually this is a situation for the ISP to resolve.

[plemans]

@Kitsap is correct.  Your power levels are all over the place and out of spec big time. 

Start with removing any amplifiers, signal attenuators, or splitters from the coax.
From there check the line for kinks, damage, moisture in the line.
Check the connectors for improperly made ends, foil touching the copper coax line, loose connections, bad/old/cheap connectors, or corroded connections. Replace them if you do.
If you can, simply connect the modem right where the coax comes into the home. This prevents wiring in the home from being the issue. And some ISP’s charge if the wiring issue is in the home. So this helps prevent this.

[dannydiggz]

Thanks for this insight. This morning the speed seems to be up again, speedtest getting 850-950 down with wired connection.

Could you humor me, and let me know what may cause it to be the way it was with the previous data I gave you... but then the next morning seem to be working properly?

This is the data given currently with the downstreaming hitting 850-950.

Thanks again for the input!

Cable Diagnostic
Startup Procedure
CM status: OPERATIONAL
DownstreamChannel: 807000000Hz Locked
ConnectivityState: OK operational(12),
BootState: OK Operational
Security: Enabled
IPProvisioningMode: 12 IPv4Only

Downstream Bonded Channels
Channel LockedStatus Modulation Channel ID Frequency Power SNR Correctables Uncorrectables
1 Locked 256 QAM 37 807000000 Hz -11.8 dBmV 36.5 dB 174684 189
2 Locked 256 QAM 1 117000000 Hz -4.1 dBmV 41.1 dB 152447 203287
3 Locked 256 QAM 2 123000000 Hz -3.5 dBmV 41.8 dB 67375 181638
4 Locked 256 QAM 3 129000000 Hz -2.6 dBmV 42.8 dB 74227 152875
5 Locked 256 QAM 4 135000000 Hz -2.3 dBmV 43.3 dB 99376 206054
6 Locked 256 QAM 5 141000000 Hz -2.8 dBmV 43.4 dB 147953 240175
7 Locked 256 QAM 6 147000000 Hz -3.5 dBmV 43.1 dB 116880 121932
8 Locked 256 QAM 7 153000000 Hz -3.5 dBmV 43.3 dB 172647 234799
9 Locked 256 QAM 21 237000000 Hz -3.5 dBmV 43.9 dB 7741 6547
10 Locked 256 QAM 25 735000000 Hz -9.4 dBmV 38.9 dB 358 711
11 Locked 256 QAM 26 741000000 Hz -9.2 dBmV 39.1 dB 370 422
12 Locked 256 QAM 27 747000000 Hz -9.0 dBmV 39.2 dB 345 376
13 Locked 256 QAM 28 753000000 Hz -10.0 dBmV 38.4 dB 439 335
14 Locked 256 QAM 29 759000000 Hz -10.7 dBmV 37.7 dB 403 490
15 Locked 256 QAM 30 765000000 Hz -10.5 dBmV 37.8 dB 344 629
16 Locked 256 QAM 31 771000000 Hz -11.3 dBmV 36.9 dB 426 904
17 Locked 256 QAM 32 777000000 Hz -12.9 dBmV 35.4 dB 728 1034
18 Locked 256 QAM 33 783000000 Hz -13.2 dBmV 35.3 dB 9040 1317
19 Locked 256 QAM 34 789000000 Hz -12.3 dBmV 36.2 dB 10764 1223
20 Locked 256 QAM 35 795000000 Hz -12.5 dBmV 35.9 dB 57216 851
21 Locked 256 QAM 36 801000000 Hz -12.1 dBmV 36.3 dB 391670 358
22 Locked 256 QAM 38 813000000 Hz -11.6 dBmV 36.7 dB 445165 221
23 Locked 256 QAM 39 819000000 Hz -11.5 dBmV 36.7 dB 3029465 4117
24 Locked 256 QAM 40 825000000 Hz -11.3 dBmV 36.9 dB 5417430 27326
25 Locked 256 QAM 41 831000000 Hz -12.3 dBmV 35.6 dB 4822947 2888861
26 Locked 256 QAM 42 837000000 Hz -13.9 dBmV 34.4 dB 2972506 607205
27 Locked 256 QAM 43 843000000 Hz -13.8 dBmV 34.5 dB 9907784 1932283
28 Locked 256 QAM 44 849000000 Hz -15.7 dBmV 32.6 dB 15260348 4551535
29 Locked 256 QAM 45 855000000 Hz -14.9 dBmV 33.5 dB 17719429 5325461
30 Locked 256 QAM 46 861000000 Hz -14.5 dBmV 33.9 dB 1189302 82194
31 Locked 256 QAM 47 867000000 Hz -14.9 dBmV 33.5 dB 15375984 4417840
32 Locked 256 QAM 48 873000000 Hz -14.5 dBmV 33.8 dB 690591 69845

Upstream Bonded Channels
Channel LockedStatus ChannelType Channel ID SymbolRate Frequency Power
1 Locked ATDMA 1 5120 Ksym/sec 17600000 Hz 48.5 dBmV
2 Locked ATDMA 2 5120 Ksym/sec 24000000 Hz 47.8 dBmV
3 Locked ATDMA 3 5120 Ksym/sec 30400000 Hz 46.5 dBmV
4 Locked ATDMA 4 5120 Ksym/sec 36800000 Hz 46.0 dBmV
5 Not Locked Unknown 0 0 Ksym/sec 0 Hz 0 dBmV
6 Not Locked Unknown 0 0 Ksym/sec 0 Hz 0 dBmV
7 Not Locked Unknown 0 0 Ksym/sec 0 Hz 0 dBmV
8 Not Locked Unknown 0 0 Ksym/sec 0 Hz 0 dBmV

Downstream OFDM Channels
Channel Channel ID Frequency Power SNR/MER ActiveSubcarrier Correctable Uncorrectable
1 159 300000000 Hz -3.0 dBmV 43.7 dB 296 ~ 7895 187387696 1
2 160 918000000 Hz -15.6 dBmV 31.9 dB 2216 ~ 5975 187387696 1

Upstream OFDMA Channels
Channel UpstreamMuted RangingStatus Subc Zero Freq ActiveSubcarrier SymbolsPerFrame Power
2 False Success 36.8 MHz 148 ~ 1907 12 41 dBmV
2 n/a Other 0 MHz 0 ~ 0 0 0 dBmV

[plemans]

Your power levels are still way out of spec. 

All the channels would be within 3.5dbmv of each other. And for optimal speeds, they should be from -7.5dbmv to 7.5dbmv. You're wayout out side of the power window and your channels are way further apart than 3.5. 

the reason your still getting speeds with be the ofdma channels. They allow the higher throughput. But when there's issues/congestions on those channels, it uses the standard channels. And I"m betting you have issues of the ofdma channels as well but we don't have as much to compare with. 

So while your speeds are back, its probably not going to stay stable

[dannydiggz]

Appreciate this info! Makes sense to me.

So I had this installed by a Cox tech less than a year ago, and I haven't moved anything/changed anything wires wise that they put in place. I actually don't use cable for TV, so I have no boxes or any other devices using the signal. If I call Cox to have them fix this --- are they going to try to charge me? I'm assuming yes?

I rent my place, so I can't really do too much myself as the wires/connections are only partly accessible by me. I just am not sure what I can really do other than have them get involved - but I don't see why I should be on the hook for it as I didn't set it up - and it seems they "Got me connected" and said good enough.

Oiiii

Thanks again you guys! Will followup. -DD

[Kitsap]

Being in a rental situation, there are limits as to what you can access and check.  Are you in a single family unit or do you have some close neighbors that could be experiencing the same issues?

You still pay Cox a monthly fee to deliver a service.  A lot of things can change/deteriorate in a year that are the responsibility of Cox and you are the only one being affected.  It is not unusual to have to push a service provider to deliver reliable consistent service.  If you do not push, no one else will and they are happy to collect the monthly fee and go on down the road.

Here is a link to some details that might help you.  Clearly some do not apply.  Look for the details that may resolve your issue.

https://www.duckware.com/tech/solving-intermittent-cable-modem-issues.html

Agree with @plemans, your power levels are still a long way out of specification.

[Kitsap · Accepted solution]

Just took a second look at your latest cable data.  It appears Cox has enabled mid-split in your area.  I can see your OFDM channel 2 is running at 918 MHz and the power level is way below specification.  There is a good chance Cox did that in the past year.

Whether you only use one connection or not, there could be a splitter in your coax connection.  Many old splitters are rated for 5-860 MHz and cause a significant signal loss above that frequency range.  The splitter needs to be replaced.