I've been an Electronic Tech since '72..The Radar I worked on was all tube except a 300 volt PS that used 4 diodes in a bridge for the locale oscilator,,those were the days,,don't know electron flow unless you know tube theory and to me thats a fact,,just retired from the Fed Govt. in '04 at FT Rucker (Army Aviation Center),know that CW 5's exist..I believe pilots need prior college to be accepted,not in the area I was in..
Heh...they were still teaching vacuum tube theory at NAS Memphis in 1974 when I went through there..