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[RFI] Fw: Comcast/Xfinity X1 service

To: <rfi@contesting.com>
Subject: [RFI] Fw: Comcast/Xfinity X1 service
From: "Paul Christensen" <pchristensen@ieee.org>
Date: Thu, 25 Jun 2015 10:56:31 -0400
List-post: <rfi@contesting.com">mailto:rfi@contesting.com>
On Thu, 2015-06-25 at 12:03 +0000, Bill Price wrote:
I personally don't care for Comcast internet service. You see, the
problem with Comcast internet service is that the bandwidth is shared
by all your surrounding neighbors that also use Comcast.

That's a near-quote from a telco's propaganda department, also known as
marketing.   Cable topology is truly a broadband service while ADSL/DSL is
truly a baseband service.  Compare performance with distance.  When data is
up-converted to RF, data rates mostly remain unaffected with changes in
coaxial distance.   Being a baseband service, performance of DSL is far more
affected by changes in line distance.

Before becoming an attorney, I was a corporate engineer for AT&T Broadband
and Comcast.  My responsibilities included fiber systems network design as
well as IP telco and high-speed data traffic management for AT&T's eastern
markets.  Please don't confuse RF sharing with data sharing.  The DOCSIS
cable modem standard does not allow for the sharing of data the way you
think it does.

As David Cole points out, data is aggregated at some point into the
distribution but for cable systems, that aggregation generally occurs at a
serving fiber-optic hub site.  Each hub site typically serves between 10K
and 30K passings.  Each fiber-optic node will serve anywhere between 5 and
500 passings, depending on geographic and population density.  Here in
Jacksonville, the average node size is 500 homes.  In the City of Miami,
with high density passings, we ran 1550 nM lasers to nodes that feed only
five homes, on average.

I'm no longer in that business.  But given a choice between cable or DSL
through a local telco, it's a no-brainer.  N4CC and I operate a remote
internet site on the FL/GA state line.  The only internet service available
is through Windstream, a DSL service provider.  We are stuck with a maximum
600 kbps upstream speed.  While that's enough for basic operation of our K3
rigs, it is not nearly enough to bring back pan and waterfall information
from an SDR receiver.

The Comcast service footprint ends about five miles to the south of the
site.  One option is to work with a Comcast subscriber at the service
fringe, then run a high-power Wi-Fi link between locations.  As much of a
headache it is to go to this length and reach the cable service area, it's
worth it for the significantly better transfer speed.

Paul, W9AC
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