Detectors


Philmore with Galena


Home Made Crystal Stand


Razor Blade and Pencil Lead


Carbon Edges with Sewing Needle


Beam with Pencil Lead


Razor Blade Edges


Testing Combinations


Home Made Base to Match Xtal Set


Home Made Razor Blade and Pencil Lead Stand


Diodes

If you have built crystal sets in the past, then I will be preaching to the choir.
If you are new to this let me say a few things about detectors.  These are passive
detectors.  They rectify the ac signal into pulsating dc.  It is easy to build a crystal set.
It is not easy to build a good crystal set.  Many variables complicate our task.  Every
Part of the crystal set play an important part, from the antenna to the head phones.
The detection can be performed by many simple items.  A good diode will always
be best.  That said you must play with detectors, they are amazingly fun.  Take notes
as you learn.  If all else in your crystal set is good then the detector will control
how loud and sensitive your set is.  When you have a good working set sort through your
diodes by trying  them one at a  time without re-tuning  your set.  One  or more  will be
the best diode for volume.  Use this diode as your standard for testing detectors.  Do not
use a audio amplifier when testing detectors, use head phones.  The first stage of your
audio amp can act as a detector giving you false results.  When testing detectors use German
Silver or Phosphorus Bronze for your cats whisker.  Cut the tip of your cats whisker with scissors
not side cutters.  You want a flat end.  Try all the rocks in your collection.  Pressure is important
too little or too much changes the results.  Rectification can occur by the fact there is a natural
semiconductor or dissimilar materials and or imperfect contact. 
I like my double razor blade detector with the edges up,  you can place many objects on the
blades and see what happens, it is quick and easy.  I like the beam detector using pencil
lead, it is quick and easy to change materials to see what works.
When it crackles in your phones just move it a little or bang on the table to make
it come alive.  Have fun.