[mythtv-users] Way OT: High-speed Data Service Delivery

Jay Ashworth jra at baylink.com
Wed Jul 13 13:21:12 UTC 2011


----- Original Message -----
> From: "Ian Clark" <mrrooster at gmail.com>

> Sorry for diving in a bit here, and apologies for my ignorance, but
> surely the propagation speed over copper is approx the speed of light,
> and over fiber it /is/ the speed of light (in whatever medium the
> fibre is made of?)

In fact, not quite.  The ratio is called Velocity Factor, and in some types
of coax, it can get down as low as 66% of c; it has to do with capacitance
and the dielectric material.  In optical fiber, yes, I think it's about .99c.

  http://en.wikipedia.org/wiki/Velocity_factor

Cheers,
-- jra
-- 
Jay R. Ashworth                  Baylink                       jra at baylink.com
Designer                     The Things I Think                       RFC 2100
Ashworth & Associates     http://baylink.pitas.com         2000 Land Rover DII
St Petersburg FL USA      http://photo.imageinc.us             +1 727 647 1274


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