Great to have actual measurements of the practical range of my whistles.... (or voice for that matter, I have a pretty strong voice, but I can't shout at maximum for more than just two minutes before I have to lower the volume or go completely hoarse).


From their charts I deduce that I shouldn't expect people to notice my whistle at 500 meters (unless perhaps in favorable conditions) ... but at 200 meters there's a pretty good chance they will notice. In my book, that's great to know.


200 meters doesn't seem as much, but it is in fact quite some distance in the woods. Lots of people can be in a 200 meter (600 feet) radius and you won't even notice them. If there's a trail within 200 meters, people on that trail should be able to hear you.


To increase that range - does anyone have ideas of how to improvise low frequency sound devices? A makeshift drum is obvious, but perhaps there is some other techniques for squeezing low/medium frequency sounds out of some garbage or equipment? I don't think a drum will attract much attention beyond "curse that hippie, he can't even play". Hopefully, if you bang long enough someone will turn up to tell you to keep quiet.