Help: Bat detector

[Shafik Harmoni]

zeier at urz.unibas.ch wrote:
: I'm interested in buying a bat detector (makes bats "hearable"). Does anyone 
: know a company which sells them (Here in Switzerland I didn't find one)? 
: I would apreciate general hints about these devices too (Don't know much 
: about it).
: Thanks in advance. 

I'm guessing here, but does it shift the inaudible bat sonic emissions
down into human hearing range?  Maybe a parabolic dish with headphones?
Or does it use radio wave reflections to track the target?  Possibly,
it detects their infrared signature and plots it on a miniature cathode
ray tube in an eye-piece?  Or maybe resonance in the bat wings it found 
through laser refraction?

In any case, I hope you blow those little #@%$%#$s out of the sky!

Shafik.