This is for a kit to build a pair of crystal radios and one earpiece, Two Crocodile clips for earth and aerial included. Colour of components may vary.
Soldering skills required to build the boards.
If you require ready made please email.
One postage charge for as many kits as you want.
No coils to wind, tuning is by on board tuning capacitor, with tuning screwdriver provided.
If you are fascinated by power free radios then this may interest you. Ideal for portable use, hiking, camping, etc. Or a decorative piece of jewellery!!
Each germanium diode and earpiece is selected for optimum performance.
A fun little radio, just clip aerial and earth crocodile clips to the test points on the board. Crocodile clips included but you will need to provide the aerial and earth wire.
Frequency received are popular AM stations ie, Talk Sport and Absolute Radio.
You can change the inductor to change the frequency range.
Build instructions for Earring Radio
1. Solder resistor 82K Ohm (Grey Red Black red)
2. Solder Inductor 220uH ( Red Red Brown Silver)
3. solder germanium Diode ( Any Way around)
4. Solder 120pF Variable Capacitor ( Any Way around)
5. Solder the phono socket, ensue the plastic lugs fit into the holes on the board.
6. Solder the two test point connections for aerial and earth.
7. A small hole at the top of the board is used for ear-ring.
Getting Started .Plug the headphones into the socket. Holding your thumb behind the socket when plugging in will avoid any stress on the solder joints.To get the strongest signals in your area you will need to experiment if you need both an earth and an aerial. In some cases just an earth will pull in strong signals. Check the earth on both the earth and aerial pads. When hiking camping etc. You can clip the earth or aerial clip to a fence or metal structure. If many stations are breaking through on the same setting this is an indication that the aerial is not required. Two crocodie clips are provide to connect an aerial and earth wire ( not included in KIt)
Adjusting the tuning. Use the small screwdriver provided to adjust the variable capacitor on the board. The capacitor rotate continuously from maximum to minimum, then increase again. Technical description. Approximate frequency range : 970KHZ to 3.6MHZ
You will need to experiment, in some cases just a good earth is all that is required. Metal water pipe is ideal. Signals will usually be stronger in the evening. If selectively is poor and a few stations breaking through together, try shortening the aerial. Experiment with different aerial lengths to obtain the optimum performance in your area.
Detector – Germanium diode.Earpiece supplied– High impedance crystal earpiece.
Fault finding. If no sound is heard then check the earpiece on a powered appliance, sometimes in transits the earphones “lock up”.
Circuit diagram can be downloaded from poldhuradiokits.com