[mythtv-users] OT: OTA HD

[Brian Wood]

On Monday 22 December 2008 14:35:22 Travis Tabbal wrote:
> On Mon, Dec 22, 2008 at 2:31 PM, A JM <vbtalent at gmail.com> wrote:
> > Interesting topic guys and terrific information!
> >
> > My TV only has a single coax input - is there a way to combine
> > over-the-air channels with the cable company cable into a single source?
> >
> >
> >       (OA)     (CABLE)
> >
> >              \    /
> >                Y
> >
> >
> >          (TV Input)
>
> Combiners exist to do things like that. Usually for multiple antenna
> systems. Why would you want to do that with cable/OTA? Cable has the OTA
> signals on it, wouldn't it be easier to use those?

Yes, but directional couplers are uch better for that purpose.

DO NOT do what the drawing indicates, because:

Cable TV uses frequencies that are not used for TV broadcasting, some of which 
are used for aeronautical navigation.

You would be sending CATV signals out your antenna, attenuated only by the 
isolation loss of the splitter/combiner, which is usually speced at 30db., 
but is usually much less, as the isolation spec assumes all ports are 
perfectly terminated at all frequencies.

Cable systems are required to scan regularly for signals leaking out of their 
system, and in this case you would probably have a cable truck outside your 
door pretty soon, if hey are doign their job.

You will also get severe interference on the channels that are used for oTA in 
your area and also used by the cable system.

Show that little drawing to your cable system's chief engineer, and you will 
be able to see what a heart attack looks like when in progress.


-- 
beww
beww at beww.org