David Trott's Untuned Crystal Set
Thanks for the web site, information, pictures and schematics. I am attaching two photos of a crystal set that I have built. It is my fourth set. I built it in a Lane brand cedar jewelery box. I use a 75ft Radio Shack shortwave antenna and for a ground a hollow iron pipe hammered into the ground. The coil is not tapped, there are no variable capacitors. There is a 47K resistor over the phones and a 1N34A diode and Radio Shack jacks and magnet wire. The coil is a wooden dowel and it is glued to the inside of the lid. I used electrical tape over the magnet wire to insulate it from the coil as it passes over from the diode to the antenna hook up . With no tuning I hear a faint signal from one or two stations during the day. At night , thanks to propagation I pick up the world! Loud and clear too ! As you can imagine the signals are random and often overlap. Thats okay for someone who channel surfs anyway.
I am in Seabrook New Hampshire; right on the coast above Massachusetts. From this location I have at night picked up WSHP South Bend Indiana, WCBQ Monticello Maine I also hear a lot of German, Arabic, French, Chinese and British language bouncing in and out. With no controls ( an open circuit ) you are able to unintentionally scan the low end of the broadcast range.
Thanks for keeping passive radio alive. Your not the only one building these little curiosities out of left overs.
I have finished 6 radios now. Like most builders I continue to redo them. I am sending along photos of radio number five. This one uses a nice Chinese made box used to display samples of 5 small perfume bottles. Until I got a hold of it.
This set is my first attempt at using a spider web form. I reused magnet wire from radio number three; now fully disassembled. Nice features are the brass thumb nuts. the upper left is the antenna the one below it is the ground. The two in the upper right are the phones. the works are hidden under a velvet covered plate under the lid. the brass looking trim is really plastic. there are two taps on the coil and I have made my first tap switch using brass nuts and bolts. The tap connects to a 1N34A diode. there is a 47K resistor over the phones. I haven't had much time to test this out but picked up a good signal from a station playing that crazy rock 'n roll. I like swing and jazz.