So the idea came to me that it would be helpful, in the space of a few pages, to cover some of the most frequent questions that people ask - or might ask - before they purchase a device that can be quite expensive. That's not a problem for a worthwhile investment, bit it's pure waste if the wrong device is chosen and it just sits on a shelf gathering dust.
This booklet is not intended to be scientific, but rather a means of sharing 30 years of personal experience and knowledge gleaned from books,, technical papers and above all from skilled practitioners.