drops in speed in modem mode

[MattyB31]

Hi all,

I need help with intermittent speed issues. I'm on a standard 130mbs package. The Hub 3 was terrible so we switched to modem mode and added an Archer AX55 router. Everything has been great for two months and now I get regular drops in speed all the way to 0mbs in the evenings.

I'm testing the speed in wifi via the router, but the trigger for me knowing there is a problem is that the wired PS5 stops mid-use when watching Apple TV or any other streaming service we happen to be using. I used Speed.Cloudfare to check things and I can see fluctuations.

I know how to access the Log but it's only showing upstream timeouts (several). Downstream doesn't show that data. I'm reluctant to change back to router mode to log downstream timeouts as we had so many issues in router mode I can't stand to return to it and have all the disconnects etc that we had before the new router fixed it all.

can anyone help me get to the bottom of evening speed drops etc?  I had ZERO issues and no changes in my equipment up until a week ago.

thanks, Matt..

[Client62]

In Modem mode we must also consider there may be issue with our network cables and with our router.

Try 0800 561 0061 to see if there is a known fault affecting your street.

Hub Signal Level Check

Via http://192.168.0.1/ connect to the Hub in Router mode, do not login in, scroll down to "Check router status"     Use http://192.168.100.1/ for a Hub in Modem mode

Using the Hub's "Check router status" tabs check the Downstream and Upstream power levels are in spec.

Downstream Power Levels of -7 to +7 dBmV are preferred, +10dBmV is the max acceptable, with a SNR of 33dB or higher across all DOCSIS 3.0 channels. Rising error counts across many channels is a current service noise fault.

Upstream Power Levels of 35 to 49 dBmV are preferred, with QAM 64 Modulation mode across all four to six DOCSIS 3.0 channels.  Seeing QAM 32/16 is a current service noise fault.

[legacy1]

Test in modem mode with a PC no router then setup a BQM with your router.

[MattyB31]

Hi,

sorry for the delay. this is what I see:

Channel Frequency (Hz) Power (dBmV) SNR (dB) Modulation Channel ID

1	139000000	-1.5	35	256 qam	1
2	147000000	-1.5	35	256 qam	2
3	155000000	-1.5	35	256 qam	3
4	163000000	-1.5	36	256 qam	4
5	171000000	-1.4	36	256 qam	5
6	179000000	-1.2	35	256 qam	6
7	187000000	-1.2	35	256 qam	7
8	195000000	-1.4	36	256 qam	8
9	203000000	-1.4	35	256 qam	9
10	211000000	-1.2	35	256 qam	10
11	219000000	-1.2	36	256 qam	11
12	227000000	-1	36	256 qam	12
13	235000000	-1	36	256 qam	13
14	243000000	-1	36	256 qam	14
15	251000000	-0.9	36	256 qam	15
16	259000000	-0.9	36	256 qam	16
17	267000000	-0.7	36	256 qam	17
18	275000000	-0.9	36	256 qam	18
19	283000000	-0.7	36	256 qam	19
20	291000000	-0.9	36	256 qam	20
21	299000000	-0.7	36	256 qam	21
22	307000000	-0.7	36	256 qam	22
23	315000000	-0.7	36	256 qam	23
24	323000000	-0.7	36	256 qam	24

Downstream bonded channels

Channel Locked Status RxMER (dB) Pre RS Errors Post RS Errors

1	Locked	35.7	57562	66978
2	Locked	35.7	37477	27882
3	Locked	35.7	5228	26721
4	Locked	36.3	4331	30397
5	Locked	36.3	4793	30389
6	Locked	35.7	4631	31645
7	Locked	35.7	4896	30550
8	Locked	36.3	4510	27574
9	Locked	35.7	4850	25805
10	Locked	35.7	5003	22718
11	Locked	36.3	4894	20275
12	Locked	36.3	5945	18087
13	Locked	36.6	5568	16457
14	Locked	36.3	4351	15880
15	Locked	36.3	4109	14884
16	Locked	36.3	4199	14615
17	Locked	36.6	4017	15024
18	Locked	36.3	4122	16170
19	Locked	36.3	4146	16783
20	Locked	36.6	4318	17530
21	Locked	36.3	4302	17941
22	Locked	36.6	4095	18320
23	Locked	36.6	4415	18927
24	Locked	36.3	4869	19368

Upstream bonded channels

Channel Frequency (Hz) Power (dBmV) Symbol Rate (ksps) Modulation Channel ID

1	23599951	39.8	5120	64 qam	10
2	39400042	39.3	5120	64 qam	4
3	46200034	39	5120	64 qam	3
4	32600060	39.5	5120	64 qam	9

Upstream bonded channels

Channel Channel Type T1 Timeouts T2 Timeouts T3 Timeouts T4 Timeouts

1	ATDMA	0	0	1	0
2	ATDMA	0	0	1	0
3	ATDMA	0	0	4	0
4	ATDMA	0	0	5	0

network log contains many critical and error lines.

[MattyB31]

some of this is beyond my knowledge so the links aren't any good for me. Also, I don't have a PC. only a MAC.

[Adduxi · Accepted solution]

Far too many PostRS errors, usually indicative of a noisy circuit. Reboot the Hub and keep an eye on those errors. A good circuit should have zero errors.  If they continue to rise a VM tech will be needed to sort it out. 

[MattyB31]

What can cause post RS errors? Would it be a cabling issue inside the property or outside? I know the pre-install job was shoddy and I have a theory that the cable could be susceptible to damage as the installers put it under s slab that is now cracked. its right on top of the cable. Could that be an issue. 

Inside the property, the Cat6e from the hub to the router runs parallel with a mains lead. Could this be causing issues or would it need to be a physical connection thing? I can move the Cat6e if that could be part of the problem (that said, its been like this for a couple of months and the problem is new)

[Tudor]

RS errors are often caused by ingress of radio signals on the same band as used by the VM hub. This can be from terrestrial TV, DAB radio, aircraft radios etc. The ingress can sometimes be caused by users on the same street cabinet as you using non-VM coax cables or having an unterminated feed. This type of  error is extremely difficult for technicians to find and rectify. 

[MattyB31]

So when I rebooted my hub I noticed that the co-ax into the hub wasn't threaded up tight, I re-tightened this. indications are good as Post RS errors are remaining at 0, 12 hours later. I will update in due course.

[MattyB31]

It's over 48 hours since the reboot and noticing the slightly loose co-ax connection at the rear of the hub. Pleased to say we are reporting 0 PostRS errors and no noticeable drops in speed when streaming content. Fingers crossed that was the issue,

thanks :-_)