Is there any technical reason that a video preamble could not be part of your software package? As a drill I set up FlDigi to do a video preamble, showing the letters 'VARA', it was a very quick transmission, and it seemed to me like it would sure clear up a lot of confusion, on the receiving end, about what mode is being used, especially as you advance your software into utilizing the CQ mode. A button that would send out a video preamble just once, on operator input, seems like it would be a natural fit for CQ mode. Doug NS4ZM