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[marjohn56]

My line works, i dont have any issues, faster sync would be nice but compared to most I'm not doing too bad.

My question is simple, why would rain. the wet stuff, not rein, only affect the DS SNR. I would have expected any detrimental effect to be on the US side as the frequencies are higher.

My line leaves the house, goes over the road to a pole then I assume goes underground to the cab. The fall and rise is quite rapid even with a sudden heavy downpour. Night time SNR hardly varies if it's dry.

If it was water seepage I would not have expected the recovery to be quite as quick, unless the trunk is sitting in the drain!

Any thoughts?

Edit - Title corrected by Admin at request of OP

[JGO]

I wonder - water has a dielectric constant of about 80 compared with 1 for Air.
 Also it is a polar molecule and from memory this means adsorption bands at various frequencies. A drop between insulated conductors might have such a selective effect; it needs figures which I haven't got.

No doubt Black Sheep will shoot me down in flames !!

[waltergmw]

Hi marjohn56,

It might be worth asking how the figure is produced, given your modem is at the start of the upstream path rather than at the far end.

Kind regards,
Walter

[marjohn56]

These are figures produced by DSLStats, so by the modem, I assume it is getting the info from the DSLAM. The drop varies depending on the severity of the rain. Normally hovering around 10.5db, I've seen it drop to 6.0 which is roughly where my US SNR is, it's never gone lower though. As I say, it's not causing any issues I'd just like to understand what's going on, is it common to see this for instance.

[lloyd]

I see similar behavior. My d/s is also affected, but to nowhere near the same degree.  And it does not take rain, a heavy mist is sufficient.  Here are a some graphs from today.  The rain mid morning was hardly enough to wet the pavement.  My incoming line is overhead.

[marjohn56]

Here's a perfect example from last night

[roseway]

That's UPstream which is affected mainly.

[marjohn56]

You are correct, I must move the 'D' and the 'U' caps on my keyboard!

I always meant US and not DS...

I need a holiday, my brain hurts!

[roseway]

 

It still doesn't explain the phenomenon of course. Very occasionally I see a similar effect on the upstream only, as below.

[marjohn56]

Your DS SNR is lower than mine but your US is higher. I deduce from that that you are further away from your DSLAM than I am from mine, but that you have a better line than I do.

I think I want a bit of cable like yours...

[roseway]

My copper line is about 220 metres, and initially I got the full 80/20 speeds with plenty of margin to spare. But over the months I've gained a lot of crosstalk. The only reason my downstream SNRM is as low as it is, is because I haven't resynced since the most recent crosstalk disturber appeared. When I do resync my DS speed will be lower.

[tickmike]

Here's a perfect example from last night

I do Not see anything .!

[marjohn56]

It's the green thingy going up and down, its above the red thingy..

[GigabitEthernet]

I don't see logically why rain should affect broadband at all?

It would only affect it if there was water ingress, wouldn't it?

[burakkucat]

It would only affect it if there was water ingress, wouldn't it?

I agree. It is a puzzling situation.