Paul810,

If my memory serves me correct, the lower the tone the farther it can reach (natuarly depending on the output "energy". Like radio frequencies, the long wave reaches thousands of klometers while the shortwave depends on bouncing against a layer in the stratosphere and Earth and so on.

The ACME 2000 also seems to use 2 frequencies and I wear earplugs when I use it so loud it is.

Best Scouting wishes from Holland,

Bagheera