On Sat, 03 Feb 2007 11:06:38 +0000 (GMT), "Dave Saville"
<(E-Mail Removed)> wrote:
>On Thu, 01 Feb 2007 21:31:37 +0000, Roderick Stewart wrote:
>
>>What are the cable run lengths like? Words like "barn" suggest quite
>>big distances are involved. If the feeds to the two buildings
>>effectively amount to a Y-shaped arrangement, with either branch
>>comparable to a quarter wavelength at ADSL carrier frequencies, which
>>I understand go up to about 1MHz, then it might act as a quarter wave
>>stub and cancel at some frequencies causing the unpredictable results
>>you describe. For 1MHz, a quarter wavelength would be 75 metres, so if
>>the cable runs are comparable with that, this could be the cause.
>
>No cigar I am afraid - "It's 40 m from the pole to barn and 20 m to the house."
>Junction box on barn to NTE5 is at most 3m and is drop cable. On the house it
>is drop cable for 4 m or 5 m into the house, a really old junction box, and
>"normal" inside type BT cable for maybe another metre to the second NTE5. As I
>said pulling the faceplate from this one makes no difference. I can't (legally)
>isolate it any more than that. :-)
If I understand correctly from your original description, the ADSL
modem is in the barn/office, which is 30m from the end of the line,
which is in the house, or in other words, the ADSL modem is not at the
end of the line. Is this right?
Admittedly the run lengths you give suggest that problems would only
occur at higher frequencies, but I still wonder if there could be
enough cancellation to intervere with the waveform of the ADSL signal?
If I'm right about your cable geography, it might be worth trying the
modem at the end of the line instead of 30m from the end, and with
nothing connected to the intermediate point. Otherwise I'd have
thought there was a fault on the modem, but you say you've tried two
different ones with the same result, which would suggest it is
something to do with the cabling.
Rod.
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