[mythtv-users] General Set-Up Question

Brian Wood beww at beww.org
Fri Jun 2 13:31:49 UTC 2006


On Jun 2, 2006, at 7:03 AM, sschaefer1 at woh.rr.com wrote:

> It seems to me that all the responses have been in reference to having
> some sort of
> frontend computer next to the television, which is fine... but I
> thought I might mention an alternative.
>
> I set up a MythTV system, that has the backend and frontend on the
> same system. Using coax, I output the video from MythTV system to a RF
> modulator which converts the video signal to a television channel that
> is put onto the coax cable, which is then run to the television. As
> long as I'm tuned to the that channel on the television I can see the
> output.
>
> I use infrared distribution in my house, which the hardware I use is
>  equipment for running signal over the coaxial cable. This
> way I can use the infrared remote to control the MythTV from where the
> television is.
>
> In your case of describing only one television is super simple and
> barely would cost anything extra, especially compared to having a
> frontend computer. However, as an example of my setup, I
> have all the televisions in my home connected to the coaxial network,
> with includes the aerial antenna off the roof, which I use a RF low
> pass filter to block out channels above 47 and insert the RF modulator
> channels every other channel to 69. Since I'm not using any high
> definition
> televisions yet, I record HDTV shows with a HD capture card from the
> antenna,
> playing them back in a SD format so I can watch them on the SD
> televisions in the house.
>
> Caveats: RF modulators don't have the same audio spectrum as a
> baseband signal coming directly from the computer or a DVD player, so
> you lose a
> little bit of quality... hard to describe, but NOT a big deal to me ~
> which is on par to how the audio from a DVD movie sounds as opposed to
> when a local network station airs the same movie. Infrared
> distribution was a daunting task when I first looked into, but once I
> bought
> the minimum of equipment and I realized it was really quite simple, I
> think the fact that I research things to death before buying equipment
> helped.. including downloading and reading equipment manuals. Similar
> experience with setting up a RF distribution.
>
> One consideration I had when I setup my RF distribution, is rather
> than worry about, or have to trouble shoot, merging a set of RF
> modulator signals with the incoming antenna reception... I could
> simply put all the RF modulators on the coax cable without the antenna
> signals (and modulate on any channel I'd like), and run the antenna
> signal directly to the VCR and use the VCR to
> change channels on the antenna, but I would have to watch the
> broadcast shows on channel 3 which the VCR would broadcast on, because
> most VCRs have a built in cheapo modulator that can modulate on
> channel 2/3 or 3/4.
>

In addition to the audio limitations that you mention there are also  
video limitations. First of all you are pretty much limited to SD  
material, as creating your own ATSC RF signal would be expensive and  
non-trivial.

Even with SD video, the quality of consumer grade modulators is  
pretty limited. You could purchase a modulator of the type used in  
CATV headends, but those cost around $3000, even more if you want to  
have MTS audio, and that's per-channel, probably cheaper to purchase  
a separate PC.

Still, if the quality available is adequate for your purposes you are  
quite correct about the flexibility of in-home RF distribution  
systems. You can also put things like outside security cameras, baby  
monitors etc. on the system, and you can distribute material other  
than TV signals, like FM audio, custom data, intercom channels and  
even modulated IR control for your RoboSapien.


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