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Question on audio/video signal extension...

Last response: in Graphics & Displays
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December 8, 2004 5:08:45 PM

Archived from groups: rec.video.desktop (More info?)

There are plenty of posts on how long can RCA runs before
degradation...etc.

My specific situation is this: A video camcorder (DV or Hi8) will be
shooting (record or not) in a gym. The video signal is intended to be
displayed in another room within the same building but with a distance
of about 80-120 feet (cable run). The display will be either a 27" TV
or a DLP projector (at 40-60"). The purpose is to allow people who are
sitting in the room to observe (video/audio) the performance (dance,
singing) happening in the gym.

I'll say the quality expected is no where needed to be broadcast/pro
but good enough to allow people in the room to enjoy the performance.

What is the most economic way to achieve this?

I think the video can be sent through RCA composite (yello/red/white)
for quite some distance, but the audio probably can't. Some people
suggest using a DI and run balance for the audio part, or some
transformer and phone wire (which I don't understand). I'm pondering
modulating both audio/video signals to RF and use tv-cable and use a
demodulator (VCR) at the other end. Another guy suggest using those
2.4GHz wireless sender/receiver, but I think it's not gonna work as
there're too many concrete walls in between plus it's suspectible to
interference when there're people walking around.

My key is low cost and good enough to have a 'tv-signal-quality'
experience.

How about computer at both end using ethernet.... too weird :) 
Thanks....
Ernest
December 8, 2004 6:34:32 PM

Archived from groups: rec.video.desktop (More info?)

> Obviously the easy way is to modulate the signal at the camera end
> and put a TV at the other end. If there is noticeable loss then you
buy
> an RF amp. Don't expect it to be very pretty though.

Yeah I have one of those 1-to-4 splitter+RF amp from Radio Shack. On
the other hand, for the RF modulator itself I've seen prices various a
lot from $20 to $200+. Any suggestion?

> The computer at both ends is interesting though. I can get pretty
good
> performance (less than perfect), playing DV across a 10/100 network.
> The DV can easily get into the computer using a IEEE-1394 port.
> The trick is what software would take in the video/audio at one end
> and have it displayable at the other end in real time. If you hook
the
> plasma to the computer at the other end, it should look pretty good,
no?

Yeah... so what software you use to stream the video?

Ernest
Anonymous
December 8, 2004 10:30:50 PM

Archived from groups: rec.video.desktop (More info?)

"ernest" wrote ...
>> Obviously the easy way is to modulate the signal at the camera end
>> and put a TV at the other end. If there is noticeable loss then you
> buy
>> an RF amp. Don't expect it to be very pretty though.
>
> Yeah I have one of those 1-to-4 splitter+RF amp from Radio Shack. On
> the other hand, for the RF modulator itself I've seen prices various a
> lot from $20 to $200+. Any suggestion?

Ordinary composite video (yellow RCA jack) running through
200 feet of real RG-59 coax will look far better than modulated
into RF and run through even 3 feet of coax.

>> The computer at both ends is interesting though. I can get pretty
> good
>> performance (less than perfect), playing DV across a 10/100 network.
>> The DV can easily get into the computer using a IEEE-1394 port.
>> The trick is what software would take in the video/audio at one end
>> and have it displayable at the other end in real time. If you hook
> the
>> plasma to the computer at the other end, it should look pretty good,
> no?


There are devices used in home theatre and distribution systems
that run audio and video over ordinary CAT-5 computer network
cable. Far more straightforward and maintainable than anything
involving computers and software.
Related resources
Anonymous
December 9, 2004 2:26:56 AM

Archived from groups: rec.video.desktop (More info?)

"ernest" <ernestsiu@yahoo.com> wrote in message
news:1102543725.572319.136340@f14g2000cwb.googlegroups.com...
> There are plenty of posts on how long can RCA runs before
> degradation...etc.
>
> My specific situation is this: A video camcorder (DV or Hi8) will be
> shooting (record or not) in a gym. The video signal is intended to be
> displayed in another room within the same building but with a distance
> of about 80-120 feet (cable run). The display will be either a 27" TV
> or a DLP projector (at 40-60"). The purpose is to allow people who are
> sitting in the room to observe (video/audio) the performance (dance,
> singing) happening in the gym.
>
> I'll say the quality expected is no where needed to be broadcast/pro
> but good enough to allow people in the room to enjoy the performance.
>
> What is the most economic way to achieve this?
>
> I think the video can be sent through RCA composite (yello/red/white)
> for quite some distance, but the audio probably can't. Some people
> suggest using a DI and run balance for the audio part, or some
> transformer and phone wire (which I don't understand). I'm pondering
> modulating both audio/video signals to RF and use tv-cable and use a
> demodulator (VCR) at the other end. Another guy suggest using those
> 2.4GHz wireless sender/receiver, but I think it's not gonna work as
> there're too many concrete walls in between plus it's suspectible to
> interference when there're people walking around.
>
> My key is low cost and good enough to have a 'tv-signal-quality'
> experience.
>
> How about computer at both end using ethernet.... too weird :) 
> Thanks....
> Ernest
>
Kind of like a webcam?

It's kind of a long run for unbalanced audio, and I'm skeptical that
the video would arrive in very good shape either. You could get
lucky I suppose. It would be safer to at least have an amp at the
sending end.

Obviously the easy way is to modulate the signal at the camera end
and put a TV at the other end. If there is noticeable loss then you buy
an RF amp. Don't expect it to be very pretty though.

The computer at both ends is interesting though. I can get pretty good
performance (less than perfect), playing DV across a 10/100 network.
The DV can easily get into the computer using a IEEE-1394 port.
The trick is what software would take in the video/audio at one end
and have it displayable at the other end in real time. If you hook the
plasma to the computer at the other end, it should look pretty good, no?

David
Anonymous
December 9, 2004 6:01:28 AM

Archived from groups: rec.video.desktop (More info?)

>From: "ernest"

>
>I think the video can be sent through RCA composite (yello/red/white)

I've done this exact thing over a 100' run from yellow to yellow with no loss
of video quality. Cheap and easy. I haven't tried it with audio...

Chase
Anonymous
December 9, 2004 7:46:49 AM

Archived from groups: rec.video.desktop (More info?)

On 8 Dec 2004 14:08:45 -0800, "ernest" <ernestsiu@yahoo.com> wrote:

>There are plenty of posts on how long can RCA runs before
>degradation...etc.
>
>My specific situation is this: A video camcorder (DV or Hi8) will be
>shooting (record or not) in a gym. The video signal is intended to be
>displayed in another room within the same building but with a distance
>of about 80-120 feet (cable run). The display will be either a 27" TV
>or a DLP projector (at 40-60"). The purpose is to allow people who are
>sitting in the room to observe (video/audio) the performance (dance,
>singing) happening in the gym.
>
>I'll say the quality expected is no where needed to be broadcast/pro
>but good enough to allow people in the room to enjoy the performance.
>
>What is the most economic way to achieve this?

Just hook up the cables. Half that distance is generally not a
problem -- you can get A/V cables that long in stores.

For the audio, the problem is picking up interference, not signal
loss. So how well shielded the cable is, and how electrically noisy
the environment is, makes a difference.

>I think the video can be sent through RCA composite (yello/red/white)
>for quite some distance, but the audio probably can't. Some people
>suggest using a DI and run balance for the audio part, or some
>transformer and phone wire (which I don't understand). I'm pondering
>modulating both audio/video signals to RF and use tv-cable and use a
>demodulator (VCR) at the other end. Another guy suggest using those
>2.4GHz wireless sender/receiver, but I think it's not gonna work as
>there're too many concrete walls in between plus it's suspectible to
>interference when there're people walking around.

Running balanced audio reduces the interference issues. If you
happen to have an audio mixer or direct box available for borrowing,
you can use that. This sort of distance is everyday stuff for
stage/band work.

You could also use a preamp or active distribution amplifier halfway
along the path to boost the signal. Anything with audio line in and
out will do the job. For that matter, the same applies to the video
-- just set up a VCR halfway along the route, hook cables in and out.

>My key is low cost and good enough to have a 'tv-signal-quality'
>experience.
>
>How about computer at both end using ethernet.... too weird :) 

Possible but you'd have to mess around with the hardware and
software to do it, and unless you know someone who has it handy, that
means spending more money.
--
*-__Jeffery Jones__________| *Starfire* |____________________-*
** Muskego WI Access Channel 14/25 <http://www.execpc.com/~jeffsj/mach7/&gt;
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!