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Standard User Stoatwblr
(newbie) Wed 12-Dec-12 21:02:28
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ADSL2 spectral dropouts?


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I've been monitoring the DSL spectrum on my router and noticed on several occasions the entire set of carriers between 800 and 1600kHz dropped out for a couple of seconds.

Frequencies above and below this were unaffected. The dropouts coincide with streaming video stopping, so I don't think I'm looking at browser glitches.

Monitoring software doesn't spot this as the sampling periods are too long.

Any ideas?

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Standard User BatBoy
(legend) Wed 12-Dec-12 21:24:13
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Re: ADSL2 spectral dropouts?


[re: Stoatwblr] [link to this post]
 
RFI maybe? That's slap bang in the AM MW radio band. Do you have an old MW radio you can tune in, turn on and hear the drop outs?


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Standard User Stoatwblr
(newbie) Wed 12-Dec-12 22:54:45
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Re: ADSL2 spectral dropouts?


[re: BatBoy] [link to this post]
 
Yes, I thought about that too, but as far as I know there are no HF hams within a mile of the cable run.

There are clear RFI notches at the frequencies of the stronger AM stations in SW london.

Interestingly, while watching it some more, there have been several more complete dropouts along with dropouts of other spectrum chunks, all coinciding with throughput glitches.

The ISP is talktalk and I'm using a Fritzbox.

If someone has software (linux) which is better able to track the dropouts I'd be very interested. I very much doubt OpenRetch has any interest in hooking up spectrum analysers to monitor this kind of issue.

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Standard User Zarjaz
(knowledge is power) Thu 13-Dec-12 21:25:41
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Re: ADSL2 spectral dropouts?


[re: Stoatwblr] [link to this post]
 
It won't be a radio ham anyway.

You'd be surprised how easy it is to monitor this kind of stuff using the bits per bin graph on a JDSU/Exfo.

To my mind, your biggest issue is persuading TT to actually recognise your line has an issue.

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