acl wrote:Another thing that confuses me is the original Cop McDonald's system is somewhat slightly different from the SSTV being used by amateurs in the 1980s and I found that I could not decode the SSTV files on this forum using a PC based decoder but I could decode the following...
Steve Anderson wrote:
The majority of PC based SSTV viewers require a VIS code at the start of each frame, the original Cop McDonald system didn't have or need them, so most of the PC-based software fails on a signal without a VIS code 'header'.
I believe that JVFax software can be used with this original format, it's mainly for Faxes, but does 8-second B&W SSTV too...but I'm no expert on it, Harry may want to add something here...also being DOS-based you may need to run it in a DOS-box...again I'm no expert here...
I should remind all, this device handles only the original Cop McDonald B&W format, both US & EU line/frame rates at 120 or 128 lines.
None others. It doesn't understand VIS codes or handle any modern format. The base-band analogue output mentioned in the previous posting should provide a signal for an exter nal unit to handle those other formats. At this stage I have no intention of developing such a device - though that may change one day...but there are plenty of PC apps (and some smartphone apps) that do handle the more modern formats, so I doubt I'll ever get around to it...
I believe there is a VIS code for the 8s 120/128 B&W format - more research required...that could be added quite simply into a modulator...even though this device doesn't need it and would simply ignore it.
JVFax is these days called JVComm32, whether it still supports this original 8-second B&W mode I don't know...it's now Windoze based...
Harry Dalek wrote:....i just don't know why they all just ignore the classic SSTV ...
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