New SVGA cable problem - strange one

[jasper1106]

Hello everyone,

This problem is baffling me, so I imagine that I've missed something simple.

I recently bought a 15m SVGA - SVGA male to male cable.

I am trying to connect my PC to my LCD TV.
Once plugging the cable in, PC nor TV detect a signal, even though the graphics card is set to "dual screen". (Nvidia 7900GS).

I have a much shorter VGA cable which is only 2metres in length so I moved my PC closer so I could hook up my LCD using my older cable.
The signals were successful.

If I then unplug the old cable and try the new one the picture becomes stable, however any changes made through the PC to the display or a reboot forces the signal to be lost.

It's like the new cable cannot initiate the signal itself?
Obviously I do not particularly want to move things around the room just get the PC and TV to talk to each other.

Why does the new cable work after the older cable picks up the signal?

Your help would be very much appreciated, thank you!

 

[Justin]

From this site:http://www.scala.com/hardware/dvi-vga-cable.html :

VGA

VGA-Analogue is not going to have as long a range. Using high quality cables I would say that 10 meters would be the maximum for 1024x768@60Hz. There are VGA-Analogue repeater solutions as well that can also permit 10's and 100's of meters of signal--at lower
resolutions--e.g. 800x600@60Hz.

So, what I suspect you are experiencing here is that when you have this longer cable attached, the excessive length is preventing your video card from detecting the proper display settings for your display. Even though the connection itself might function, without that critical signaling during the configuration phase, the video card thinks that something is wrong.

 

[jasper1106]

Hi there,

Thank you for your quick reply! I know the "VGA" is the older standard cable, I was recommend to get the "SVGA" which is a high quality shielded cable.

The older cable (shorter) one I have I believe is VGA and the one that works for the "config phase" as you put it.

Why do they make these cables this long (15m) if there's a chance the actual signal isn't strong enough to initiate the "hook up"?

Many thanks for any further info.