Using a signal mirror takes about five minutes practice (if that)), particularly when you only need to pinpoint your location. Signalling "behind" you is not all that difficult Just remember that angle of incidence equals angle of reflection in all planes and hold your mirror more in the horizontal. I have also heard of using two mirrors although I have never tried it. And after all, what piece of equipment doesn't require some practice?

In one situation, I signalled the helo, about ten miles distant. The pilot knew our location before he took off, which certainly simplified his job.

As you can tell, I am a fan of the signal mirror (which has often been the mirror on my compass). Of course, it does work better in sunny Arizona than in the PNW.

Come to think about it, in terms of actual compass use, I have used my compass about as often as a signal mirror as I have used the north pointing needle function.....