Composite Video Distribuition / amplifier

[rauloliv]

Hi guys,

Sometime ago i was asked to do a simple composite video switchbox for a bar.
4 inputs from sat receivers -> 4 outupts to video projectros / LCD tvs
Cables are RG6 and video is from composite output. The cable lenght is not the same for all the screens, shortest is 5 meters, longest is about 25 
The goal was to be able to select the input for each screen, alowing the same input to be displayed in multiple screens.

What i done was a mechanical switchbox with 4 quality rotary switches (one for each output).
Selecting the same input on 3 or 4 outputs would decrease the video quality a bit  but my client was aware of that and was happy with it.


Now they have made some changes on the bar moved all the receivers to the upper floor and the sat receivers also changed. Now i'm facing some problems when selecting the same input to more than one output - loss of video quality (low contrast picture) but the worst is ground loop interferences ( horizontal bars on picture)

The simple solution that comes to my mind would be just adding amplifiers on the 4 outputs. Could this solve the problems i'm having?
Any sugestions?

Thanks

[nihilism]

http://www.krameraustralia.com.au/products/model.asp?pid=1010&sf=49

http://www.extron.com.au/product/product.aspx?id=mavavrcaseries&subtype=130&s=4

[SL4P]

Amps on each output is what you should have done first time.

Or at the least - used a passive 75R source splitter to isolate/set the source impedance of each output - and terminated each end-of-cable.

The other alternative is to daisy-chain the video (in-out-in-out-in-75R) - with no termination at each drop  - except the last (end of cable) TV.

[rauloliv]

http://www.krameraustralia.com.au/products/model.asp?pid=1010&sf=49

http://www.extron.com.au/product/product.aspx?id=mavavrcaseries&subtype=130&s=4

Funny as the Kramer device phisicaly is very much identical to the one i built.
Costs more than 500usd ?! Would love to see whats inside

Amps on each output is what you should have done first time.

Or at the least - used a passive 75R source splitter to isolate/set the source impedance of each output - and terminated each end-of-cable.

The other alternative is to daisy-chain the video (in-out-in-out-in-75R) - with no termination at each drop  - except the last (end of cable) TV.

Can you elaborate more on this?
I know i left the thing unfinished, but because at that moment it suited my friends needs i left it to work as it was.

Regards,
Raul