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Intermittence in Downstream/Upstream

On our wavelength

Hi there.

The problem - To keep a long story as short as possible - For the last week or so we have been experiencing intermittence in overall connectivity both in downspeed and up. The upstream is very noisy as per what the router settings display, with SamKnows tests frequently reporting back 20mb/s or less. Downspeeds appear stable until they are not. They've always been far lower than the "up to" maximum but that's okay, I'm used to it as we're in a very over-subcribed area it would seem. Perhaps utilisation spikes is to blame? Occasionally we will get complete connection drop-outs for moments at a time though it's mostly extreme slowdown for several minutes at a time before it recovers. This will either happen once or twice a day usually around early-mid afternoon and/or at peak time. The router may flash briefly in that time too, as if trying to update firmware though this has never usually been a consistent issue. Needless to say I'm full WFH though not under my own roof. I am also NOT the only person having this issue after having spoken to neighbours. The alarm has been raised to VM by several but of course, no movement.

The first time I called the support line was yesterday and was told there's an issue in the area though the VM fault line was not reporting the same thing. Today I called back to check on it and was told there's no issues and that yesterday was "short term" but... well, the below table presents a different picture. I'm growing tired of being given a different answer every time I ask. The last guy I spoke to on the phone said I'll be called back by a supervisor in the next 2 hours. Hasn't happened. They said they'd raise it to "Network Assessment Management Team" but I'm unsure if that means it'll be checked properly, so I'm raising the complaint here too.

3.0 Upstream channels

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

14960000045.0205995120 KSym/sec16QAM1
24310000044.5205995120 KSym/sec16QAM2
33660000044.5205995120 KSym/sec16QAM3
42360000044.0205995120 KSym/sec16QAM5
53010000044.2705995120 KSym/sec16QAM4

Looks familiar. Also fairly regular T3 Timeouts. I won't claim to know specifics on that, I'm no network engineer of course but it's clear similar problems are happening but now the downstream is affected as well? Weird.

Some background - (1) August last year we had similar issues with Upload specifically. This was sorted in a few days after a problem was found on the network side. SNR.

(2) In December last year we were riddled with the same issue for over 2 weeks with no movement from VM on checking the network until I'd managed to speak to management by a complete miracle who escalated it after 2 failed tech visits, as well as regular correspondence with a staff member here, providing evidence via PingPlotter, router status, BQM and overall patterns. Once again, it was found to be an SNR issue on the network and was finally fixed shortly after.

Needless to say, to see the same or similar problem appear potentially appear a 3rd time is quite grating at this point. I know it's not my end, I can see that very easily especially when it's a repeat of the same issue and others close by are also having the same. Tech visits back in December (before the issue was finally escalated) replaced a bunch of parts in the box outside, connections were tightened etc. and they've remained that way since. Router is restarted semi-regularly. A friend in telecommunications was also able to confirm that this issue would not be my house. I'm sure the latter is something you hear a lot to try and push VM along, but going down a script feels very pointless by now. I'm sorry about the tone, but I'd really like this to not be another 2-3 week back-and-forth. Any help is appreciated. Don't think a regular engineer visit is going to be of much use this time.

Thanks for reading.


Very Insightful Person
Very Insightful Person

All your Upstream should be 64 QAM for a start.  This would suggest noise somewhere in the circuit. 

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Hiya, Adduxi.

Yes, when it's stable that is what appears when all is well. Very much a mirror of previous network issues. Truth betold ever since the last fix, it's never been consistently 64 on all channels but somehow my upload was not affected. However, when things have gone awry daily as of late, they are all dropping to 16 or 32 and staying there until the intermittence has passed.


5 Upstream channels at QAM 16 could be a noise issue affecting several homes.
Check for a known fault in your street via 0800 561 0061 it is an automated service.

Hello, Client.

It's sadly still reporting no faults as mentioned somewhere in my post, hence why I'm wanting this to be escalated due to the similarities to previous issues that, after much back-and-forth with VM, both turned out to be network-wide issues. 😞


I'm not sure if I'm allowed to post actual images here but this is speeds at time of posting. Very little upload (recently been upgraded to 100mb/s) and even downstream is struggling when we're on Gig1.


We can post images provided they don't contain personal info or the Public IP of the Hub.  Looking at your Realspeed test, the speeds are all below the minimums for Gig1.  VM's engineers are going to be required to resolve the noise issue.

On our wavelength

Problem still present today. Phone support said the request to networks had been sent successfully, but the fault line still isn't reporting any faults. Still no callback either, naturally. Really not sure what options I have left 😞


We will call back means "please put down the phone" & I will mark the call as "Closed, Customer hung up".

Until VM book an engineer to investigate the noise on your installation OR the 0800 561 0061 number reports a local fault, expect nothing to happen.

On our wavelength

All too familiar with supports undertones, yeah. This was just not typically that since it wasn't the usual "call back in 24 hours" spiel. I suppose it amounts to the same thing, though. They didn't seem to want to book an engineer to the property though, even if I'm almost certain they'd find nothing and just blame my PC or something stupid (this actually happened once). However as mentioned in my original post, this intermittence is never even picked up by engineers and they're never willing to escalate to networks. Unsure why it's so difficult to do so with a recurring noise issue such as this.

I'll hope a forum staff member will see this then.