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[kapt69]

Hi Folks
Have at last got PC back - have been using laptop via wifi to NetgearDG834GT - connected via NTE5 faceplate BT master socket. (With disconnected ring wire).
I had noticed, having set up routerstats to help with a problem, that when making/receiving a telephone call the SNR margin goes down by approx 1db. No problem as we don't get that many calls.
When I got the PC back (connected via cable to same Netgear router) I firstly noticed small spike when cable was inserted from router to PC(08.50 on attached graph) then a drop of approx. 1db when PC powered up. (09.00 - 10.00 approx. on graph)this recovered when PC switched off.
Since I'm struggling to keep up my SNR margin/speed/IP profile, I could do without this drop.
Any suggestions gratefully received.

[attachment deleted by admin]

[orainsear]

Do you have another Ethernet cable that you can try?

When you inserted the cable, was the PC powered off at the wall?

[kapt69]

Hi
Thanks for reply.
First's easy - no, but if you think it may help I can go & buy one.
Second mmmmmm. pretty sure I plugged in cable THEN plugged in power to back of PC.

[orainsear]

Try replicating what you did before and monitor what happens.

[kapt69]

Hi
PC currently 'occupied' grinding away though a back-up.
Will try when available, though margin dropped again this pm when PC was turned back on.
I'll keep an eye on things when I switch off after back-up.
Cheers

[kapt69]

Hi
Have been away for a few days - haven't had time to buy new ethernet cable - BUT - noticed that SNR margin dropped by over 1 db when PC just turned on (NOT CONNECTED TO ROUTER).
I have just done some admin on it then returned to wifi connected laptop to monitor stats whilst PC shut down.
I watched the SNR rise from 10.4 to 11.9  !!!!! Unplugging ethernet cable after this doesn't seem to make any difference. Power to PC,monitor, router etc is through a Stanley (Belkin) surge protection distribution gizmo.
This may be perfectly explainable - but could someone who understands these things please explain?? Obviously a 1.5db difference makes me want to stick to the laptop - but that's my wife's and I would like to stay happily married for a little while longer.
Thanks

[roseway]

It sounds as though your PC or its monitor may be radiating some interference. At a guess I would say that it's more likely to be the monitor. If you've got a medium-wave radio you could try tuning it away from any station and then moving it around near the PC and monitor. If this is the problem, then moving the router as far as possible from the PC is about all you can do (apart from replacing the equipment of course).

It could also be mains-borne interference from the PC or monitor, and putting the router on a separate mains socket away from the PC might help.

[Smoke]

I have had something similar happen to me. It turned out that it was the PSU (power supply unit) in the computer.

If it's a cheap nasty one it can be awful for both ADSL and radio as they leak RF across the spectrum. To show how common it can be I have had it happen twice in two different computers.

I have also had bad experiences with UPSs (Uninterruptible Power Supplies) and my ADSL in the past as these too can sometimes leak RF.

Also some motherboards in their BIOS have a feature called spread spectrum which can also help reduce the RF emitted from a computer.

Hope this helps

Mark

[kapt69]

Thanks for suggestions folks.
Not sure if we still have MW radio - will have a look.
Will also investigate moving router to different power supply (- though guess it will still be on same ring). Will also need to get a longer ethernet cable as a result, which will be an opportunity to upgrade.
Will let you know what happens.
Really grateful for the advice - much appreciated.

[kapt69]

Hey ho!
Before going out to buy armfuls of cable I tried moving router as far from PC as possible - given length of cables.
Powered up router via extension lead from another socket and tried shielding router with tinfoil  (don't laugh!!)
Good news: turning off monitor showed no improvement - so - don't need a new one of those presumably.
Bad news: turning off/on PC had same drastic effect, even at maximum distance (admittedly only about 1.5 ish m - without ethernet cable connected.
(Am now wondering if this thread ought to be posted on hardware forum?? - no doubt will be advised  -  if so apologies to all.)
So. . longer master socket - router cable to be purchased. Not sure about buying ethernet cable yet, as if it turns out I need the router out in the shed to be 'protected', then I may need a 20m one rather than 'just' a 5 or 10!!
Before anyone suggests throwing out the PC - don't think I haven't thought of that!
You would have thought PCs & routers could be mates wouldn't you? 

[sevenlayermuddle]

Kapt,

I don't know if anybody's mentioned it yet, but you ought to keep the router cables (both phone lead & ethernet) well away from any mains wiring, not forgetting any wiring that may be inside your walls.

If the interference is being passed via the mains wiring (which sounds possible), then rearranging the cables as above make quite a difference.

- 7LM

[kapt69]

Hi 7LM
Phew - for a moment there I thought you were going to suggest re- routing the walls. - there is a limit!
Seriously - thanks for advice - I believe some cables have better 'shielding' than others - I'll try & see if the helpful young people in the computer shoppe know of such things - and I'll do my best to keep them as far away from 240v as possible.
Regards
K

[kapt69]

Anyone want to buy an 'as new' 10m super high speed ADSL RJ11 to RJ11 - only used once. Cost over £20 - offers!!!!!
Note to admin guys - before you axe please read previous threads!
From this you may gather new cable didn't affect things one iota. Tried router other end of house - pretty sure different power ring. Adsl cable strung away from as much 240v as I could (back will soon recover from ducking under - don't worry!)
Oh yes - & added to all this - when I got back from shopping spree, having left laptop + routerstats up I found masses of 2 - 3 db spikes recorded. Also whilst watching saw the lights flickering - we do get this sometimes - not on & off - just for a spell every week or so. Walked up & down lane 200 yds each direction. No circular saws etc that I could hear.
Needless to say I waited for things tosettle before trying new cable - just in case you think I'm completely gaga. (Sorry got to be careful now there's a lady of same!)
I guess you may detect just a slight note of hysteria in all this . . . . .   

[Ezzer]

An obvious neat thing to sort your cabling is to coil them up to keep things tidy. unfortunately this makes the cables loop antennea either transmitting or reciving more electrical noise. the dsl lead from microfilter to router is best laid out  and away from other cabling and transformers, mains etc and not running parralel for and distance with another cable. a simple re arangement of the cabling mght help.

Check your monitor to pc cable has a small cylindrical bit part way along the cable, you can get replacements from places like maplins, look up ferrite rings. is the router sitting right by something electrical, that may be a source of backround interference. Although 1-2db difference isn't normaly anything to worry about.

[kapt69]

Hi Ezzer
Thanks for that.
Cable is routed pretty much as per your suggestion - certainly may need to tidy it more eventually - but until I have solved the 'intereference' I will leave as is.
Yes the monitor cable to PC has ferrite ring fitted.
You say 1 -2 db isn't anything to worry about: well if you are talking percentages - 1.5 / say 11 = 13+% I would have thought that was fairly significant?  Especially when I am only just hanging on to an IP profile of 1000kbs ( and that is now currently reduced to 750 - presumably as result of the number of times I've switched off the router to try/move cables.)
Having tried router on different ring main and in another room (approx 5 -6m from PC) - not forgetting these latest 'tests' have been done without any ethernet cable from PC to router, I am left wondering what else it could be. Next on list is to try again to find a MW radio as Roseway suggested.
Would I be right in thinking a 'noisy' PSU should not really affect things in another room? If still likely I guess another visit to the PC repair shop is on the way.
As an aside I have been wondering if updating the firmware on the Netgear would improve router's ability to cope with these reductions?? I have seen this mentioned - but can't find how one goes about it ( and therefore whether my limited tech. ability could manage it.)
Regards
K