A 3-band shortwave crystal radio

Radio overview

This is the latest model i made. Nearly all components are home made except the small test circuit i've added to hear if there is actually any transmitting in the ether.
The radio consist of three seperate coils that can be switched in with a switch on the side. I've added a top dome to proctect from dust.





Vario capacitor Again making the vario capacitor was the hardest part to do. This time i did some calculations and according to it i needed 60mm2 of plates covering each other. To do this i used some PCB or copper plated epoxy board used for making printed circuits boards.


Vario capacitor This is the bottom view. Here you have a better look at the variable condensator and the band selecting switch. The small yellow thinggy is the antenna trimmer.






Capacitors A closer look at the top side without the protecting dome. The crystal i used is pyriet or also known as fools gold. The wisker is just a plain safety pin.