The 'Russian woodpecker' and the US' OTH-B systems built decades ago used pulsed signals of 1 Million watts and up, with gigantic antenna arrays. [0] Comparison

The 'Russian woodpecker' and the US' OTH-B systems built decades ago used pulsed signals of 1 Million watts and up, with gigantic antenna arrays. [0] Comparison to WSPR is impossible (esp. given the complete lack of non hand-wavey details in the article). If the method were at all feasible, it'd very likely be commercially available). [0] https://fas.org/nuke/guide/usa/airdef/an-fps-118.htm https://fas.org/nuke/guide/usa/airdef/an-fps-118.htm