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PostPosted: Thu Dec 27, 2007 3:14 pm 
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Joined: Thu Mar 02, 2006 5:42 pm
Posts: 410
Location: middleton wi usa atsc
I would like to see an ATSC RF Modulator for sale.

Currently I use tvout (svideo) and feed it into an RF NTSC video modulator ($40) and mix it back into my antenna coax system on an unused tv channel (42 in my case) so I can watch mythtv on any, or all, tvs in the house just by tuning to channel 42. With an ATSC RF Modulator (with component video inputs, for instance) you could feed it from MythTV and watch it on any HDTV in the house without any loss of picture quality. You could have several frontends, each on their own channel.


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PostPosted: Thu Dec 27, 2007 3:27 pm 
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Joined: Thu Sep 30, 2004 11:29 am
Posts: 2419
Location: Mechanicsburg, PA
Hi!
jzigmyth wrote:
I would like to see an ATSC RF Modulator for sale.

Currently I use tvout (svideo) and feed it into an RF NTSC video modulator ($40) and mix it back into my antenna coax system on an unused tv channel (42 in my case) so I can watch mythtv on any, or all, tvs in the house just by tuning to channel 42. With an ATSC RF Modulator (with component video inputs, for instance) you could feed it from MythTV and watch it on any HDTV in the house without any loss of picture quality. You could have several frontends, each on their own channel.

Interesting! I'll check with our relevant suppliers and see if they have any such device.

EDIT: FYI, your proposed implementation of the system wouldn't give you audio. You'd need something to accept the digital audio and digital video and send it as ATSC. You may find it cheaper to re-cable with HDMI in the walls than it would be to have an ATSC modulator for each backend :)

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PostPosted: Thu Dec 27, 2007 3:32 pm 
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Location: Mechanicsburg, PA
If you did want to consider HDMI hubs, here are some that we could get: http://www.audioauthority.com/product_list/hdmi

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PostPosted: Thu Dec 27, 2007 6:31 pm 
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Joined: Thu Mar 02, 2006 5:42 pm
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Location: middleton wi usa atsc
Human wrote:
EDIT: FYI, your proposed implementation of the system wouldn't give you audio. You'd need something to accept the digital audio and digital video and send it as ATSC. You may find it cheaper to re-cable with HDMI in the walls than it would be to have an ATSC modulator for each backend :)


The NTSC RF modulator that I am currently using has left and right audio and s-video inputs, so I assumed the ATSC RF modulator would also have audio along with video inputs.

I guess HDMI is a possibility, but the house is already wired with antenna coax to every room. Pulling 8 or 10 runs of HDMI through an existing two story house isn't very appealing! I see from the hub's user manual that it has a 50 foot limit on output cables, that might be enough - not sure. It doesn't allow for multiple channels, but they might make remote controlled switches, too.

It just seemed like an ATSC modulator with audio and video would be a nice clean solution for existing houses already wired up with 75 ohm cable.

Thanks for looking!
Zig


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PostPosted: Thu Dec 27, 2007 7:04 pm 
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Location: Mechanicsburg, PA
jzigmyth wrote:
The NTSC RF modulator that I am currently using has left and right audio and s-video inputs, so I assumed the ATSC RF modulator would also have audio along with video inputs.

Ah, ok. Just making sure you knew it needed separate audio inputs. Some of the RF modulators work over coax where audio and video are on the same cable.
jzigmyth wrote:
I guess HDMI is a possibility, but the house is already wired with antenna coax to every room. Pulling 8 or 10 runs of HDMI through an existing two story house isn't very appealing!

Certainly :) The only thing I can suggest is that it'd be a great opportunity to add other wiring like gigabit-capable ethernet cable, too.
jzigmyth wrote:
I see from the hub's user manual that it has a 50 foot limit on output cables, that might be enough - not sure. It doesn't allow for multiple channels, but they might make remote controlled switches, too.

Audio Authority also has some devices that redistribute video over ethernet cables (although they just use the cabling and don't transmit packets, AFAIK).
jzigmyth wrote:
It just seemed like an ATSC modulator with audio and video would be a nice clean solution for existing houses already wired up with 75 ohm cable.

Thanks for looking!
Zig

You're welcome! I'll let you know if I come across anything else. If you're interested in any of those Audio Authority options, let me know.

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PostPosted: Sat Dec 29, 2007 1:14 am 
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Joined: Fri May 21, 2004 11:55 pm
Posts: 1206
Location: Silicon Valley, CA
While it sounds inviting to re-broadcast a high-def picture with ATSC in your home, if you think it through you'll see why it is not possible.

1. The content of the ATSC signal is already encoded as an MPEG-2 transport stream. It takes up to 20M bits/sec for a full HDTV signal with one HD and one SD stream.

2. The format of your component video cable is ANALOG. It would need to be first digitized, then converted to MPEG-2 to be ready to transmit.

3. The format of HDMI is digital, but it would need to be encoded as MPEG-2 to be ready to transmit.

The uncompressed video stream available from HDMI is pretty large. It takes 24 * 1080 * 1920 * 30 = 1493M bits/sec instead of 20M bits/sec. There is nothing which will encode this at reasonable price today.

Maybe setting up a backend and multiple frontends is the way to go.

-- Joe

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PostPosted: Sat Jan 19, 2008 12:49 pm 
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Joined: Thu Mar 25, 2004 11:00 am
Posts: 9551
Location: Arlington, MA
Passive/quiet cooling components.

Especially chipset and video card HSF replacements.

BTW - Nice to see the Nexus fans. Next time I run out (only one left in the parts box right now) you guys will be my first choice to restock.


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PostPosted: Sat Jan 19, 2008 1:08 pm 
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Joined: Thu Sep 30, 2004 11:29 am
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Location: Mechanicsburg, PA
Thanks, tjc! I'll see if I can find a good source of passive heatsinks.

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PostPosted: Sat Jan 19, 2008 3:16 pm 
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Joined: Thu Mar 25, 2004 11:00 am
Posts: 9551
Location: Arlington, MA
FWIW - The ones I have successfully used in the past are the Zalman aluminum and Thermalright heat pipe ones.


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PostPosted: Mon Jan 28, 2008 6:56 pm 
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Joined: Sat Sep 02, 2006 9:17 am
Posts: 359
I'd like to see a ready-to-go front end Machine
-SFF
-silent or at least very quiet
-HD-playback capable
-LCD (probably mutually exclusive with SFF)
something like one of the mac-mini wannabes

Maybe the "Dragon Mini" Think you could call it the "Mushu" w/o being sued by Disney?


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PostPosted: Tue Mar 18, 2008 9:24 am 
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Joined: Thu Sep 30, 2004 11:29 am
Posts: 2419
Location: Mechanicsburg, PA
jmckeown2 wrote:
I'd like to see a ready-to-go front end Machine
-SFF
-silent or at least very quiet
-HD-playback capable
-LCD (probably mutually exclusive with SFF)
something like one of the mac-mini wannabes

Maybe the "Dragon Mini" Think you could call it the "Mushu" w/o being sued by Disney?

Sorry for the delayed reply - I've been working hard on the next KnoppMyth release.

When the time comes to do another round of hardware, I'll keep this flexibility in mind. I conducted a poll recently ( http://knoppmyth.net/phpBB2/viewtopic.php?t=17854 ) and the overwhelming majority of respondents are interested in keeping costs down, so I will need to balance things like reduced size with cost concerns. The way to handle the LCD would be to choose a case that comes in two versions: one with LCD, and one without. That way, nobody is forced to get it, but if they want it, they're using the same case layout as everyone else.

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