I think one is the rate in strikes per minute and the other is the delay between when a strike happens and it appears on your map.
I've been tempted to make a sferic detector for years.
Blitzortung.org is a network of volunteers with detectors who 'power' lightningmaps.org.
There's also a Blitzortung android app.
Neil
Edited By Neil Wyatt on 14/07/2018 19:43:55