[mythtv-users] mythtv newcomer.. need help setting up live tv

Cory Papenfuss papenfuss at juneau.me.vt.edu
Wed Oct 20 18:48:15 UTC 2004

On Wed, 20 Oct 2004, Evan Burrows wrote:

> I appologize to everyone for looking nieve I am just new to this stuff
> and i appreciate the help that you guys are giving me.
> Grant:
> I'm afraid the term "coax cable" is so vague it's meaningless.
> What is that "coax cable"? Is it composite video, modulated RF
> with NTSC on channel 3, analog audio, digital audio, what?
 	You have a right to be confused... "coax cable" has so many 
potential meanings in this context that it's fairly worthless.  All it 
really means is how the cable is physically constructed... i.e. with 
"co-axial" conductors.  Round hollow conductor, with another conductor 
down the middle.  It generally is termed to distinguish between older 
"flat" conductors (300 Ohm in US).  The end you put on the cable is 
irrelevant WRT the "coax" part, but it actually determines the signal on 
it.  Here's a few possibly options for "coax"

Baseband Audio:
 	Analog	(RCA-style connectors, usually red/white)
 	Digital a.k.a. "SPDIF" (RCA-style connector, usually black)

RF-modulated audio:
 	FM radio (F-style connector.  FM-audio on RF signal)

Baseband Video:
 	Composite (RCA-style connector, usually yellow)
 	Y/C a.k.a "S-vid"(two coaxial cable internally, but 4-pin mini-DIN
 	Component (RCA-style connectors.  Three (Y, Pb, Pr))
 	RGB	(RCA or BNC-style connectors.  Three (R, G, B))

RF-modulated video:
 	Broadcast (F-style connector.  Channels spaced for broadcast)
 	Cable TV (F-style connector.  Channels spaced for cable

RF-modulated digital datastream:
 	Broadcast HDTV (F-style connector.  8-VSB modulation)
 	Digital cable (F-style connector.  Usually QAM modulated with or
 		without encryption)
 	Satellite (F? BNC? N? TNC?  Don't have one so don't know)

 	Any of those (with the possible exception of S-vid, but probably 
some more I'm not recalling) can be and often are referred to as "Coax." 
See... clear as mud.


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