Otona No Kagaku Crystal Radio Kit|
Otona No Kagaku, or 'Science for Adults' is a 'mook' series published
by Gakken in Japan.
Very classy design too, that diamond weave coil design is a real eye catcher.
It includes a diode that you can use as a detector or if your feeling like
playing with the cat's whisker a bit you can use the tow mineral samples. The
reception isn't as good as with the diode but you get the true crystal
experience with this method. In the base of the radio is a small battery
operated amplifier so you can use the radio without a super long antenna.