General Discussion
  >> General Broadband Chatter


Register (or login) on our website and you will not see this ad.


Pages in this thread: 1 | 2 | (show all)   Print Thread
Standard User Banger
(eat-sleep-adslguide) Tue 21-Feb-12 21:03:46
Print Post

SNR drops as weather gets warmer.


[link to this post]
 
Anyone else noticed this. I am running my SNR target at 1.5db and when it gets cold it can rise to 2.5db, but as the weather has warmed up it has dropped to 1.1db, particularly today. Might have to force a resync unless the router does it itself.

Tim
www.vivaciti.net & freenetname
Billion 7800 on 24 Meg Variety LLU
My Broadband Speed Test
Standard User DrDeath
(member) Tue 21-Feb-12 21:13:44
Print Post

Re: SNR drops as weather gets warmer.


[re: Banger] [link to this post]
 
Whens its cold the copper contracts and the line effectively becomes shorter i think.

When its hot the opposite happens and the line becomes longer ?

_ _ _ _ _
Stage one: Signed up for pipex 1pm May 31st
Stage two: Received Email verification with order number 6 pm May 31st
Stage three: Sent old 56k modem off to pipex by special delivery June 1st 10:30 am
Stage four Received Email Telling me login details have been sent 1st class, and activation within 10 working days prior to firther line tests smile 13:30 Thur 6th June
Stage Five ACTIVATED june 11th 6 days early !!!!!!!!!!!!!!!!!!!!
Standard User epyon
(committed) Tue 21-Feb-12 21:20:37
Print Post

Re: SNR drops as weather gets warmer.


[re: DrDeath] [link to this post]
 
Not sure

i find my line more stable in the summer.

BE*Unlimited 16968/1353Kbps @ 6db INP0
TalktalkEssentials 15788/1254Kbps @ 6db INP0


Register (or login) on our website and you will not see this ad.

Standard User Banger
(eat-sleep-adslguide) Tue 21-Feb-12 21:21:43
Print Post

Re: SNR drops as weather gets warmer.


[re: DrDeath] [link to this post]
 
In reply to a post by DrDeath:
Whens its cold the copper contracts and the line effectively becomes shorter i think.

When its hot the opposite happens and the line becomes longer ?


I see, interesting, could be the reason.

Tim
www.vivaciti.net & freenetname
Billion 7800 on 24 Meg Variety LLU
My Broadband Speed Test
Standard User MHC
(legend) Tue 21-Feb-12 23:15:29
Print Post

Re: SNR drops as weather gets warmer.


[re: Banger] [link to this post]
 
Unlikely given the amount of change in length and diameter.

Even if the change in length made a measurable change in attenuation then the change in diameter along that length would have the opposite effect. Shorten line >>> decrease attenuation. Reduce Diameter >>> increase resistance and thus attenuation!





~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~


M H C


taurus excreta cerebrum vincit
Standard User b4dger
(knowledge is power) Wed 22-Feb-12 11:42:37
Print Post

Re: SNR drops as weather gets warmer.


[re: Banger] [link to this post]
 
My line also seems to like the cold!
Perhaps it's down to copper conductivity slightly improving when cold so lowering the attenuation?

Temperature and Conductivity

Standard User ian007jen
(member) Wed 22-Feb-12 11:52:19
Print Post

Re: SNR drops as weather gets warmer.


[re: b4dger] [link to this post]
 
copper conductivity slightly improving when cold


The opposite I would have thought smile ie at absoloute zero copper does not conduct.

Ian
Anonymous
(Unregistered)Wed 22-Feb-12 12:29:45
Print Post

Re: SNR drops as weather gets warmer.


[re: ian007jen] [link to this post]
 
dip a copper cable into liquid nitrogen and it will superconduct, it's a property of all metals, increased conductivity at low temperatures.
Standard User mixt
(experienced) Wed 22-Feb-12 12:55:34
Print Post

Re: SNR drops as weather gets warmer.


[re: Banger] [link to this post]
 
Always thought this was due to physics, and the laws of thermodynamics. As Anonymous has said, if things are super cooled so they become super conducting, there is no electrical resistance, and because the atoms are hardly vibrating any more (due to heat), there's no 'quantum' fluctuations being generated in the material as noise, so the noise floor of the medium is reduced. If the material is hotter, there is more energy, and so more noise.

Now on <aaisp.net> (21CN+IPv6)
Previous ISPs: Virgin Media (50Mb/Cable), Be* Un Limited, ZeN
Is Linux routing your internet connection?
Need to make BIND geo-aware?
Standard User MHC
(legend) Wed 22-Feb-12 14:30:13
Print Post

Re: SNR drops as weather gets warmer.


[re: b4dger] [link to this post]
 
In typical UK temperatures - 0o to 20o c the difference is about 0.35% per degree C so for a 10o drop there will be a 3.5% reduction in resistance. But buried cables do not change temperature rapidly! The impedance of the line is not just resistive but complex especially at the higher frequencies. It may have a little effect but not one that significantly improves data rates.





~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~


M H C


taurus excreta cerebrum vincit
Pages in this thread: 1 | 2 | (show all)   Print Thread

Jump to