i have just connected a hall projector to a laptop via bnc to vga connectors now there is a difinete signal but i have major ghosting which reduces depending on the length of the cable.
my question does anyone have any idea how to fix this
BNC to VGA from a Laptop? Do you have a BNC output from your laptop?
Try connecting to a different display device (a vga/lcd monitor) and see if you are getting the same problem. If the problem persist try wiggling the connections a bit to see whether it has a bad connection.
Finally it might be the BNC to VGA converter you are using, there are some really cheap ones out there but are really crappy. Try getting something that looks like this: