Video System theory?

[sao123]

At work I have a video system which displays a powerpoint presentation on TV stations throughout the building. A diagram can be found here...this is purely a coax video system.
http://mywpages.comcast.net/sao123/VideoSystem.pdf
One of the limitations of this coax system is the distance which good signal can be maintained...limited about 100ft for a good color TV signal.

Now. Black box now has these new Baluns which allows you to convert from coax to Cat 5/6 cabling and cable runs up to 2500 ft.

Hers my question...
Using coax we could use inline signal boosters and video distribution boxes... using the Cat 5/6 would it be possible to use a 10-100 network hub to distribute the signal?

I know a switch would not work, because a switch requires packets to operate (in 1 out 1). However a hub, merely recieves a signal, and then copies it and pumps it back out to all channels. (in 1 out all.) No packets required.

What do you think?

 

[Peter]

I wouldn't assume the signal is digital to begin with. If it's analog which I'd expect from this kind of setup, network hubs won't copy it.

 

[AbsolutDealage]

Originally posted by: Peter
I wouldn't assume the signal is digital to begin with. If it's analog which I'd expect from this kind of setup, network hubs won't copy it.

I'll second that. The black box coax>cat5 converter is only meant to convert digital signals. It is meant for locations that have an old coax network infrastructure.

The video signal is obviously analog, and unless you have an A/D converter on the input and D/A converters on all the outputs, the hub will be of no use. By the time you hack that together, it would have been faster and more cost effective to just install the signal repeaters.

 

[sao123]

The black box coax>cat5 converter is only meant to convert digital signals. It is meant for locations that have an old coax network infrastructure.

Incorrect...this converter was specifically designed for analog video systems for use in airports and schools.
Though the signal being analog...probably means the hub will not recognize it as a proper uplink to distribute.
Look on black boxes website for video baluns.

and now i answer my own question...on the next page they have a video hub, specifically for my purpose. (ill still have to try that ethernet hub though)

Balun
http://catalog.blackbox.com/BlackBo...ram=234&ig_id=343&title=Video+Baluns&related=

Hub
http://catalog.blackbox.com/BlackBo...param=234&ig_id=3924&title=Video+Hub&related=

 

[RayH]

I'm suprised that you're getting significant signal degradation after only 100'. Have you considered upgrading your coax cable? I'd highly recommend using Belden 1694A. It's RG6 quad shield with a solid copper core instead of copper on steel like most coax. Can be found for around $200 for 1000' which can be more economical than using boosters but you'll have to factor in the hassle of laying new wire.

 

[VictorLazlo]

Good RG6 will loose 1.5dB of signal over a 100' run. Old RG59 will be significantly higher (5dB+ depending on age and condition). If you are noticing significant loss over a 100' run, then you've got to replace that old cable. It may not be that difficult if you can attach the new cable to one end and use the old cable to pull it through. At the very least, you can replace the fittings. That usually helps since the fittings are where most of the wear & tear and oxidation takes place.