ISP thoughts / recomendations?

Discussion in 'Broadband' started by The Nomad, Nov 14, 2015.

  1. The Nomad

    The Nomad Guest

    Well, I've had a slowly dropping SRN(ratio) (from 8 to 5) (No idea what
    it was on first install but more than that I expect) for the last few
    weeks (months?) and decided to phone mumble-mumble this pip-emma

    Got through about 4 levels (or so) of press x to get ...

    to be told it would be at least 20 minutes before I could get to talk to a
    'real' person, and it was better to call between 12 noon and 4:30 pm - it
    was 15:30!!!!

    Oh! I hung up ...

    So do I go for 100GB from A&A for 25 UKP
    Unlimited from Zen at 21.40 UKP?

    What are either like for getting stuff fixed? (I know A&A are supposed to
    be the dog's dnagly bits ...)

    POTS is fine, quiet line check is ... well ... quiet.

    There has been a small drop in syc speed but the loop attenuation is still

    I'm currently on the TT LLU - if that helps/hinders

    Many thanks

    The Nomad, Nov 14, 2015
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  2. The Nomad

    Scott Guest

    Zen. Simply the best.
    Scott, Nov 14, 2015
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  3. The Nomad

    Graham J Guest

    All that the drop from 8dB to 5dB indicates is a small change in line
    performance. As a rule, a figure around 5dB is usually an optimum
    (depending on the exact style of ADSL) - and a higher figure indicates
    noise interfering with the ADSL signal, but this is generally coincident
    with a reduction in speed. So what you report is slightly unusual.

    However since your loop attenuation is only 12dB it is likely that your
    service is going as fast as the exchange will support - and the line is
    probably not a limiting factor.

    What speed and error counts does your router report?
    Graham J, Nov 14, 2015
  4. The Nomad

    The Nomad Guest

    The value is 'SNR Margin', so the bigger the better (if my understanding
    of such stuff is good M0HGU etc. etc.) correct? I find such a low margin
    odd with such a low attenuation.

    Down speed = 19863341

    and so far since I tried without the house wiring in parallel (test
    socket etc.) there are 5 rx errors (no tx errors) in 15 hrs it was up in
    the thousands before I pulled the 'phone' plug and re started the line
    sync. It was up to 21300000.

    The Nomad, Nov 14, 2015
  5. The Nomad

    Graham J Guest

    No, your understanding is wrong. See for example:

    There are better explanations but they may be more technical.
    Noise may well be intermittent. Lightning strikes in the area could
    cause many errors, so the error count over an indefinite time is
    meaningless. If your error count is less than on per minute averaged
    over a day or two that's quite acceptable.
    Graham J, Nov 14, 2015
  6. The Nomad

    Martin Brown Guest

    No you have it backwards. The "SNR margin" if that is what your ADSL
    modem calls it is misnamed. The thing starts off with a target noise
    margin of 6dB and tries to sync if it does then your noise margin will
    hover around that value improving (lower) at midday and worse (higher)
    after dark when continental MW stations interfere with the signal.

    If the sync cannot get a stable signal with too many CRC errors then it
    ups the noise margin in steps of 3dB and drops speed until it is able to
    obtain a self consistent solution with a low enough CRC count.

    If your line goes bad you end up in the spiral of death with line drops
    and resyncs continuing to drop speed and increase Noise Margin until it
    hits the buffers which on mine is around 256k and 18dB.

    Mine is currently stuck at 4192k @ 11dB noise margin. In good conditions
    in summer I can get around 6M @ 6dB but there are too many damp spiders
    webs in the junction boxes this time of year (actually recent flooding
    in parts of the buried phone network round here) which plays havoc with
    the line quality.
    The exact values you get are whatever your target noise margin
    translates to at the time of day you connect. If you reconnect just
    after midday you get the fastest least stable connection and if you do
    it at midnight the slowest most stable connection your setup allows.

    It is usually academic and only affects the error rate slightly but if
    you are chasing the last 64k to make HD streaming watchable then it can
    be a useful trick to resync just after midday to gain speed.

    Some modems can be persuaded to fib about their noise margin to allow a
    faster but less stable connection on a good line with advantage. Push it
    too far though and line drops will be a problem.
    Martin Brown, Nov 16, 2015
  7. The Nomad

    The Nomad Guest

    An update:

    I emailed (via the website) a question about TT-LLU and could they
    migrate etc.

    Got a call this morning from Zen answering that question and the guy was
    able to confidently answer my other questions, (some I knew the answer to
    or could work out).

    No pressure, just a real human from England with a displayed number that
    related to who he was phoning from.

    Promised to email details - which he did.

    Think they may have a new customer.


    The Nomad, Nov 16, 2015
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