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Moved to new build house, long line from Basingstoke exchange provisioned through Post Office who then got BT Openreach to do the real install. Line from front of property to internal master socket is Cat 5e & BT Engineer used ADSL v1.0 faceplate so in theory local internal house wiring is removed from the speed equation. Tested 2 Modems (Draytek 120/Speedtouch 510v4) with similar results.
From the Draytek:
--------------------------- ATU-R Info (hw: annex A, f/w: annex A) -----------
DSL Modulation : G.DMT
State : SHOWTIME
DS Actual Rate : 3584000 bps US Actual Rate : 448000 bps
DS Attainable Rate : 3968000 bps US Attainable Rate : 1044000 bps
DS Path Mode : Interleave US Path Mode : Interleave
DS Interleave Depth : 0 US Interleave Depth : 0
NE Current Attenuation : 49 dB Cur SNR Margin : 8 dB
DS actual PSD : 19. 2 dB US actual PSD : 11. 9 dB
ADSL Firmware Version : 332201_A
-------------------------------- ATU-C Info ---------------------------------
Far Current Attenuation : 29 dB Far SNR Margin : 21 dB
CO ITU Version[0] : 0000414c CO ITU Version[1] : 00004342
DSLAM CHIPSET VENDOR : < ALA >
Initial install & test by BT engineer suggested sync rates of around 6Mb, which is better than I was expecting. Initially I did indeed achieve circa 5.5Mb sync rates but stability has been variable and of late things have 'settled' at 3.5Mb sync. This is slightly disappointing so I set about monitoring modem stats using 'routerstats'. This in essence has shown that there is some interference on the line. No intereference and I'll see around a 14dB SNR margin for a 3.5Mb sync, but as you can see from the above, my line is currently in 'interference mode' whereby it gets around 8dB of SNR and clocks up quite a few (thousand) CRC errors in a short space of time. The Draytek handles the line a little better than the ancient speedtouch but there really isn't that much in in it.
The interference comes and goes as a 'step function'. ie. 1 hour it's not there, then within a 30 sec timeframe I'll see the SNR margin drop 6dB or more for a period of time. Sometimes it's an hour, today it's been on constantly from 11:40 this am. I'm logging things with a view to working out a pattern and since I've only just started (yesterday & today) patterns are vague at best
One pattern I do see is an overall change of circa 2dB SNR Margin worse at night vs day, but then I'd expect that. What I didn't expect was a 'random' step change of 6dB+ that can happen at 'any' time.....that would seem to me to be 'unusual' at best, a fault at worst.I've listened on an AM radio tuned to around 600KHz for 'stuff' and can hear quite a nasty buzz/crackling underneath everything....I'm waiting for my modem to report an improve SNR and I'll go and check the radio again to see if that buzz/crackle has gone.
So bearing in mind the above (limited stats), realistically, what are my chances of getting Post Office broadband/BT Openreach to investigate this?
Thanks in advance,
Kevin