Cat's Whisker Receiver
My crystal radio receiver, also called a crystal set or cat's whisker receiver, is a very simple radio receiver, popular in the early days of radio.
It needs no battery or power source and runs on the power received from radio waves by a long wire antenna. It gets its name from its most important component, the crystal detector as seen on the top of my crystal set. The detector cup has a piece of galena crystal in it.
A crystal radio uses only tuned circuits to select the stations, and the crystal detector to rectify the radio station's signal to enable it to be heard with a set of headphones. It is entirely passive, and it has no active components like tubes or transistors..
When you listen to a broadcast station on crystal radio the sound in your earphones comes directly from the station your are listening to. Since there is no amplification of any kind, the circuits, especially the coil, must be very efficient so that sufficient power can be recovered from the station to operate the earphones.
My version of a early crystal radio was built in my shop, with the coil form turned in the lathe, and then had the thermaleze magnet wire wound in the lathe as well. All the brass parts including the detector up top were machined in my shop also. The slider on the side is used for tuning stations, and then may be locked.
The top and bottom are made from walnut. the feet are drawer-pulls from Home-Depot. All wiring is hidden inside of the coil-form and the milled out base cavity.
The head-phones are vintage 1924 Brandies. The set is a very good performer, and is a joy to work.
Click on the photo for a closer look.....
Here is a link to my "Projects In Metal" gallery where you can see some of the other projects I've completed.....