Noise Margin

[macshac]

Hi Rik?
My reading has stabalised on a straight line with no spikes at 4db this seems a low figure compared to most reports.
Is this ok ,this low, as the line seems very stable.

[Rik]

Hi Mac

Forgive my ageing memory, but you're using a Netgear aren't you? If that is so, then it's common to see the noise margin gradually fall away, it seems to be something in the way they are built.

If you were to re-boot, I'd expect to see it go back to 6, then gradually tail off again. OTOH, on the two Netgears I've used here, they will hold sync to -2db (shown as a ridiculously large positive number in the router, but correctly by Routerstats), only at -3db will sync drop.

As long as your line holds sync, I wouldn't worry too much.

[Ray]

On the subject of noise margins anyone  have any explanations for the 2 sudden drops on the attached routerstats graph the same thing happened 3 times on Tuesday as well, not seen it happen before, I haven't lost synch. or internet at any time as a result though.

I am using a Netgear NG834 V3 router (non wireless model)

[attachment deleted by admin]

[Rik]

It would be worth changing the ranges in Routerstats, Ray, so that it peaks at 1db above your target noise margin.

I see downward spikes like that here, I've been over my wiring with the metaphorical fine toothcomb, but not found an issue. I can replicate the problem in the test socket. I just can't explain it - I'm assuming mains-borne noise, or some activity in the vicinity that I haven't sussed yet.

I take it you've done the ring wire bit?

[Ray]

It would be worth changing the ranges in Routerstats, Ray, so that it peaks at 1db above your target noise margin.

I see downward spikes like that here, I've been over my wiring with the metaphorical fine toothcomb, but not found an issue. I can replicate the problem in the test socket. I just can't explain it - I'm assuming mains-borne noise, or some activity in the vicinity that I haven't sussed yet.

I take it you've done the ring wire bit?

Thanks Rik I have now altered ranges in Routerstats.

I suspect that what I am seeing is due to something on the mains but can't figure out what it is yet, still as it's not causing me any problems at the moment I'm not too bothered.

Yes I did the ring wire bit just after I went onto Max and my router is also plugged into the master socket.

[Rik]

Might be worth trying the test socket, Ray, just to ensure that your phone wiring isn't misbehaving, in which case a filtered faceplate could be a good investment.

[macshac]

Hi Guys
Just an update. My Netgear DG834N is performing well but after a while the noise line dropped to about 4db and then straight lined.
I updated the router to the latest firmware and BINGO! the router has now returned to a straight line at 6.8db so it would seem netgear have improved the routers ability to hold on to the noise margin.
Very impressed so far with the N

[jupiter]

Netgears misreporting noise margin has been a long standing characteristic, certainly true of my DG834, which often went down to a ludicrous minus figure with no effect on the actual connection.