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Re: Topband: DSL knocks out when on TopBand

To: TopBand List <topband@contesting.com>
Subject: Re: Topband: DSL knocks out when on TopBand
From: Guy Olinger K2AV <olinger@bellsouth.net>
Date: Tue, 17 Jul 2012 09:14:51 -0400
List-post: <topband@contesting.com">mailto:topband@contesting.com>
With AT&T Uverse I had the experience of adding common mode chokes (#31
ferrite) on a long run of cat 5 and having it knock down the desired
signal.  The cat 5 is not all that well balanced, and putting the hurts on
the unbalance also knocks down the main signal which was marginal to start
with.

In the end we had to redo the layout so the long runs of cat 5 had ethernet
on them instead of  Uverse's 147 kHz through 7.9 MHz VDSL...AND...change
out the 2Wire 3800 gateway to a 3801...AND...replace the entire buried loop
from the pole into the house (550') and its umpteen splices over the years
with a continuous piece of modern shielded pairs.  In the end the little
insertion filters they have were better than anything I could wind around
the 3801.  I use the ferrite around the in-house ethernet cat5 on the TV
and PC ends.

There was a similar problem with the neighbor.  He has a 2Wire 3801 now as
well.  He also had to have his loop from the pole replaced.  I put a bunch
of ferrite on his TV side as well.

When I'm on 160 QRO, we both have a lot of corrected errors to start and
then the modem starts adjusting bit rates on individual VDSL carriers or
locking them out.  After a while there won't even be corrected errors.  The
3801 has a much better protocol than the 3800, and has hugely more
buffering for handling a flood of errors at onset of interference.  But
don't see any hits on TV, internet or phone.

Some or all of these problems will need to be solved at xDSL sites with
interference.  Quality of modem/gateway definitely can be a problem.

73, Guy
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