One thing we got a good start on at HIPAS, but never fully developed was 3D direction finding methods. This is the art of locating radio signals in azimuth AND elevation at H.F. frequencies. This was crucial for ionospheric research, but I see some major amateur applications for this...such as locating intruders way beyond the horizon...or even for search and rescue.
Originally Posted by WB5WPA
"The more you know, the less you don't know."