AM radio stations did and still do have to meet field strength readings at contour data points. (.Ground wave field strength way point readings.). Directional antennas had to be carefully maintained. to protect stations operating on the same frequency at some distance. Radials on the earth surface are more subject to change than buried ones..
73 Bruce-k1fz https://www.qsl.net/k1fz/bognotes.html Don't forget that historically many if not most broadcast stations, plus the legendary work of Brown, Lewis and Epstein, had their radials in farm fields and cow pastures, where anything on or near the top of the ground would be destroyed. Terry N4TZ _________________ Topband Reflector Archives - http://www.contesting.com/_topband _________________ Topband Reflector Archives - http://www.contesting.com/_topband
