Length wire video composite

[ICE]

What is the max length of the video (composite) wire without having
noticeable picture-quality loss?

Thanks

 

[martin griffith]

On Wed, 27 Jul 2005 12:39:47 +0200, in sci.electronics.design "ICE"
<ICE_Spam@hotmail.com> wrote:

What is the max length of the video (composite) wire without having
noticeable picture-quality loss?

Thanks

It depends what you mean by "noticeable picture-quality loss"

If its just a cheap domestic TV you can probably get away with 50m
before it gets a even more blurry.
Check the dB/m loss on say belden cables (google!) at subcarrier
frequency, ie 3.8 MHz in the US and 4.43MHz in civilised places.
See how much cable you need to get a 3dB loss at subcarrier, as a rule
of thumb
If you use crap cable, you will notice poorer quality pixs on shorter
cable


martin

 

[Joerg]

Hello Martin,

If its just a cheap domestic TV you can probably get away with 50m
before it gets a even more blurry.
Check the dB/m loss on say belden cables (google!) at subcarrier
frequency, ie 3.8 MHz in the US and 4.43MHz in civilised places.
See how much cable you need to get a 3dB loss at subcarrier, as a rule
of thumb
If you use crap cable, you will notice poorer quality pixs on shorter
cable

Also, you can compensate for increased losses towards higher frequencies
by high pass filtering. Of course, that won't work for miles of cable
where the signal is down into the noise.

Regards, Joerg

http://www.analogconsultants.com