Hi Jewel, Well, we designed one and the design is in the Smith-Kettlewell Technical file for all the good that does you unless you're into building electronics. it's called the "Little Go Beep"
An engineer with the Handyhams folks, ham radio, designed a low power gizmo that sends a single character in morse code, either repeatedly or with a motion sensor. However this was to indicate locations on a marked trail, and intentionally not very loud. I asume you don't have power at your desired spot, that means either batteries or more expensive solar panel. Do you have reliable wind? if so a wind chime is simple. Try googling "sound beacon" and see if that helps, I'll do it also. Is this for a specific unchanging location, or do you want a pootable box you can put down so as to get back to where you put it? There are those gizmos for finding your keys when you clap your hands, but they're ment for indoors and I'll bet you're out wanderin about the pasture. Tom
