Recording of long duration whistler echo train.
Sorry about the low audio, turn up the volume!
You can hear the first sferic, the "click", one second in. This is caused by a lighting strike somewhere on my side of the magnetic equator. The first whistler heard after the sferic is actually the second returning whistler, you don't hear the first one that is coupled into the magnetosphere. As the whistlers bounce back and forth along the earths magnetic field they disperse. That is, the higher frequencies travel faster than the lower frequencies. The whistlers become longer and longer with each passage through the magnetic field.
At 25 seconds you'll see/here another distinct whistler but this one is not preceded by the "click" of a sferic. This particular lightning discharge happened on the other side of the magnetic equator so I received the very first whistler from it but not the sferic.
At 34 seconds is another sferic from my side of the magnetic equator. This generates another whistler train but albeit slightly weaker.
