Daniel wrote:
> I ask because I've discovered my SNR during the daytime is 10Db higher than
> it is in the evening. Is this likely to be street lights and does it affect
> all lines?
You might want to wander over to ADSLGuide (
www.adslguide.org.uk) and
look in the "BTWholesale ADSL Implementation" forum. There is a thread
there entitled "SNR margin. Why does it dip at night" that should help
answer your question.
A precis - there seems to be two main reasons for the night-time dip.
1) In the evening, as more users go on-line the crosstalk in the cables
increases causing increased noise.
2) Radio reception at night is better and so, as ADSL uses the same
frequencies as AM radio, most lines (especially those with a lot of
overhead) pick up a lot of extra AM radio noise. This explains why the
SNR gets worse just after nightfall and doesn't fully recover to just
before daybreak. 10 dB does seem a lot though - mine only changes by 3
to 4 dB.
--
Ian
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