The history of AM radio and the invention of the mechanical sparkgap transmitters by Reginald Fessenden is absolutely fascinating.

Imagine only having telegraphs and morse code and amateurs listening every night to the spark noises in morse then suddenly in 1906 (first done in 1900 !) you hear voices and music!

https://en.m.wikipedia.org/wiki/Reginald_Fessenden

can't seem to direct link the photos but scroll down to see what you are talking about with the base of the tower being a massive insulator

scroll to: Brant Rock, Massachusetts, facility

https://en.m.wikipedia.org/wiki/Reginald_Fessenden#Rotary-sp...