Build an antique style crystal radio

Step 5 Making the Cats Whisker detector

As mentioned you can omit this step in favor of a modern Germanium Diode instead, I have decided to make the detector from scratch to make the set more authentic. I well probably install a set of terminals so that I can use a diode as well if I do not want to fiddle with the Whisker.

I actually got the plans for this detector from the book, "The Boys first book of radio and electronics" by Alfred P. Morgan. This is a really great old book with loads of information on this kind of stuff with numerous plans for crystal radios, a tube radio and tube amplifiers, I would highly recommend this and any other book by this author if you can find them.

To make the detector you well need:

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1 - 3/8" wide strip of copper 1-7/8" long
1 - piece of heavy gauge copper wire about 2-1/2" long
1 - spring from a worn out ball point pen
1 - binding post

Tools:

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- pliers
- tin snips
- strait edge and utility knife
- drill and 5/32" drill bit
- file
- soldering iron and solder

1) Start by cutting a strip of 3/8" wide copper 1-7/8" long to make the crystal holder.
2) Mark and drill a 5/32" hole in the middle of the strip of copper.
3) Using a file on edge cut teeth into the ends of the strip of copper.
4) Using a large pair of pliers with jaws that are about 1/2" wide, hold the hold the strip of copper in the middle so that the strip is perpendicular to the jaws. Fold the two ends up.
5) Bend the serrated ends over to make a set of jaws to hold the raw iron pyrite.(see photos)
6) Take the spring from the pen and straiten out one end so that it is about 3/4" long and then solder the spring to the end of the piece of bare copper wire.