[mythtv-users] HDHomerun Artifacts and can't view/watch Music Channels.

Brian Wood beww at beww.org
Sat Mar 7 19:44:10 UTC 2009

On Saturday 07 March 2009 10:44:07 Andrew Burgess wrote:
> On Sat, 2009-03-07 at 11:27 -0600, James Oltman wrote:
> > They both connect to the same splitter outside the house.
> You could try swapping the connections at the splitter to eliminate it
> as a problem.

Good suggestion. A lot of devices that look like "splitters" are in fact 
directional couplers. Hybrid splitters have equal loss to each output port, 
which DCs will have a "through" port, typically with 1 db. or less of loss, 
and a "tap" port, with anywhere from 8 to 36 db. of loss from the input port.

A DC will have MUCH better isolation from port to port than a hybrid splitter, 
and they do not depend on a proper termination of all ports to achieve this 

In other words, if you can sustain the additional loss, a DC is a much better 
device to use in splitting signal. This is what the cable company uses on the 
pole or in the pedestal, as it is the only way they can maintain the required 
isolation from subscriber to subscriber.

Generally you never saw DCs in homes, until the advent of cable modems, which 
were more sensitive to isolation and termination issues than TV sets or 

beww at beww.org

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