In message <[EMAIL PROTECTED]>, James Richard Tyrer writes: > We would hope so. What we do know is that the VGA standard is 75 ohm > and the standard impedance for BNC connectors is 50 ohms. Although > people kept putting BNCs on 75 ohm coax so now you can buy 75 ohm BNCs > but they don't have as high a frequency rating.
A local electronics store has carried factory made BNC cables in at least three impedances (50, 75 and I think 92 or 93?) for many years, and this store is not exactly fast at picking up new things. > I hate to think what the VSWR of an HD-15 pin connector stuck in a 75 > ohm coax line. Also they seem to use miniature coax. I have at least two factory made HD-15 to BNC video cables and yes, the coax is quite thin. > > And that the cables with HD-15 on one end and BNC on the other have matching > > transformers hidden inside? > > > > I'm thinking not. > > That would be nice, but they probably just have BNC on the end of 75 ohm > cable. We can hope that they used 75 ohm BNC connectors. The difference between a 50 Ohm BNC and a 75 Ohm BNC would be... different insulator/dielectric ? Jack Carroll writes: } Software Integrators sells high-quality video } cables with a VGA or DVI connector on one and and BNCs on the other. } If the project wants to } standardize on just one rear-panel connector and let the cable do the } interfacing, we could try to find out more about the DVI. In January, TM wrote: ] OGD will have two dual-link-capable DVI connectors. Now I'm seeing talk about HD-15 and BNC. Is this in addition to the DVI? Assuming for the moment that most video displays take 75 Ohm inputs, does someone make 75-to-50 Ohm matching transformers for BNC? Slightly off-topic: Speaking of matching transformers, does anyone know of a source for high quality 300-to-75 Ohm baluns? (twinlead to F, for TV and FM antennas) The ones I've found look like junk. _______________________________________________ Open-graphics mailing list [email protected] http://lists.duskglow.com/mailman/listinfo/open-graphics List service provided by Duskglow Consulting, LLC (www.duskglow.com)
