@zazzoo@wonkodon.com It's not a facet of the hobby I have played with yet! (There is so much stuff to play with in this hobby) Basically meteor comes in started burning up and leaves an ionized trail that radio waves will bounce off of. The duration can be very short but it's long enough with the right computer program and equipment. (Yes we are in the 21st century now, no refrigerator sized stuff in my shack!)