On Wed, 14 Oct 2020 09:02:51 +0100, The Natural Philosopher wrote:

There's a bit of hum on our ADSL2+ I don't think it has any effect
at
all. 50 Hz is way out of the band used by ADSL, the uplink
carriers
don't start until 26.075 kHz and the downlink ones go up to 2.2
MHz.
What does knock back the acheivable ADSL speed are strong LW and
MW
broadcast stations, which varies between day and night of course.

If the hum is really loud it *may* have and effect but then just
report a POTS vault and get it fixed.

A hum may not of itself be a problem but it is usually indicative of a
ground loop, which can be.

Agreed hum is normally down to a damaged cable and some form of
connection, damp, to ground. Mind you having said that the hum seems
a bit louder than normal ATM but the ADSL2+ has a download sync speed
of 6902 kbps and S/N ratio 7.2 dB which for 3 km of line is pretty
damn good.

With a 7.2 dB S/N ratio I'm tempted to force a resync to see if it'll
go over 7000 kbps which I never ever seen.

later Flipin' 'eck 7435 kbps 6.1 db S/N ratio using carriers up to
1.4 MHz. Be interersting to see if that stays stable overnight.
Recent "Normal" was around 6500 kbps 3 or 4 dB S/N and 1.2 to 1.3
MHz, a few years ago it was nearer 5000 kbops...

I think some one in Openreach has been fiddling, this last week there
have been a few NO CARRIER resyncs on the line in the wee small
hours. I can't imagine they are poking about in cabinets/joint posts
at that time of night. Maybe they have been upgrading the line card
firmware? NO CARRIER resyncs are very rare normally.

--
Cheers
Dave.