In the days before Radar

[emgcr]

here's an interesting link to the wonders of echo...................

https://www.youtube.com/watch?v=lLUcOFwZvyY

[slammer]

here's an interesting link to the wonders of echo...................

https://www.youtube.com/watch?v=lLUcOFwZvyY

I have seen the first one and as always I am amazed by the video, although I don´t think that the microphone of the recording does justice to what you could hear if you were in the chamber.
I would love to see this in person, however I would however probably get stuck in the tube going into the chamber.