We are busy changing over to HD so we purchased 2 NX 5 Cameras to replace our Pd 170's. We do live switching on an analog Datavideo S500 switcher using high quality cable which is about 150 meters long. The problem is we experience about a 10% drop in quality with a composite feed on the PD 170. On exactly the same feed we experience about a 25% quality loss on the NX and we have tried all the different camera settings and it makes no difference, although the on camera recording is fine.
Can someone give me some advice on this
The datavideo s500 switcher is for standard def. The PD 170 is standard def. The nx5 is hi def and only down converts through the firewire. So you're running a hi-def signal into a standard def switcher - I'm surprised you get any picture at all. You need the se2000 or above to work properly.
My suggestion is that you use an amplifier or converter.
Composite video is not specified to even work at 150 meters (That means 450 feet)at all due to the chroma and the luminance signals getting out of sync with one another.
The fact that you managed to get the pd170s to work that far was fortunate. I have had trouble getting my pd170s to work reliably past about 150 feet.
Since you are pushing the spec, you just happen to have some above average line drivers in the camera and cables. The nxcam line drivers are probably similar but not exactly the same.
Option 1. Buy a small composite amplifier/buffer. You can get cheap ones from radio shack or you can get ones for about $400 which allow you to actually add gain to compensate for the loss of signal. You can put this buffer right after the camera, or half way down the line.
Option 2. (better) use the sdi output through the bnc connector. It is specified to actually work the distance you are talking about. In this case you will need to buy an sdi to composite convertor and place it at the end of the cable run before the analog switcher. These convertors are about $1000.