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andreu1
Aspiring Contributor
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Message 1 of 6

Should noise margin drop when downloading

Ive been having problems for a little while with my connection.

I have noticed that when I am browsing the internet my noise margin is quite high

Data rate:

20.00 Mbps / 60.00 Mbps

Maximum data rate:

21740 / 82259

Noise margin:

6.3 dB / 6.9 dB

Line attenuation:

17.9 dB

 

When downloading files the stats change

Data rate:

20.00 Mbps / 60.00 Mbps

Maximum data rate:

21740 / 78250

Noise margin:

6.3 dB / 5.8 dB

Line attenuation:

17.9 dB

 

Is this normal?

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Distinguished Sage
Distinguished Sage
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Message 2 of 6

Re: Should noise margin drop when downloading

What device are you using to download, when the noise margin drops?

 

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andreu1
Aspiring Contributor
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Message 3 of 6

Re: Should noise margin drop when downloading

using hardwired pc.

Should that make a difference?

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Distinguished Sage
Distinguished Sage
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Message 4 of 6

Re: Should noise margin drop when downloading


@andreu1 wrote:

using hardwired pc.

Should that make a difference?


All computers generate a certain amount of radio interference which can affect the available bandwidth which VDSL can use.

 

This is will show as a reduction in the noise margin, and maximum data rate, in your case, its not significant. In some cases it can cause the connection to drop if the interference is bad.

 

If you are downloading, then the computer will be working harder and is likely to generate more interference.

Often its simply the internal switched mode power supply which generates more electrical noise.

 

You may be able to reduce this by ensuring that the computer is sited away from the home hub, or any phone wiring.

Some interference can be carried over the mains wiring, so a filtered socket on the computer may help.

 

Computer power supplies do have some mains filtering, but its not really that effective at VDSL frequencies.

 

I used to have an LED lighting power supply unit which caused my ADSL connection to drop, due to its plastic case and poor filtering. Its now been replaced Smiley Wink

 

Sorry if all this sounds a bit technical, but I spent many years on interference investigation.

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andreu1
Aspiring Contributor
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Message 5 of 6

Re: Should noise margin drop when downloading

Hi, No thats great information.

Thought that this may be the reason for my slow speeds.

I am connected via netgear home plugs, the actual computer is quite far away from the router.

Not sure what the interfearance may be.

Thanks again for the info.

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Distinguished Sage
Distinguished Sage
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Message 6 of 6

Re: Should noise margin drop when downloading

I suspect it is the homeplugs introducing the noise, they are notorious for creating interference. As a test, try connecting directly to the router with the homeplugs removed and see if there is any change.

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