You will need
  • Wire with enamel and silk insulation diameter 0.3-0.6 mm
  • Round ferrite rod from an old radio
  • Exercise book
  • Glue BF or nitrocellulose
  • Capacitor 1500-4000 pF
  • Terminals
  • Jacks for antenna, ground, phones
  • Phones high-impedance or low-resistance and step-down transformer (for example, the output from an old radio, TVK from an old TV or a transformer from a PA speaker)
  • The semiconductor diode the germanium point (for example, D9, D2, D18, ГД507, Д310)
  • The antenna wire is bare copper with a diameter of 3-5 mm (the antenna cord) 15-20 m
  • Wire copper stranded insulated
  • Plate of insulating material — Micarta, textolite, Plexiglas
  • Soldering iron
  • Drill
The ferrite rod to wind the strip of paper with a width of 7-8 cm. Paper wrap in several layers, securing them with glue BF to get a tight paper cylinder. The cylinder should be easy to navigate through the ferrite rod after drying.
Scheme of the detector receiver
Received a cylinder wrap 100 turns of wire with enamel and silk insulation. Wrap the wire turn to turn. The ends of the coil and secure with glue. Turned out the coil that the scheme is designated L1.
Assemble the receiver according to the specified schema. The polarity of the switching diode in this case is irrelevant. The output of the receiver connect high-impedance headphones (phones) If those are not there, you can use low-resistivity, for example, from the player. But they can only be connected through step-down transformer. In this case, the high impedance winding of the transformer is connected to the output of the receiver, the headphones to low impedance winding.
The crystal radio can't work without a good antenna and ground. Make grounding. Using flexible stranded wire connect the output to the "ground" receiver, stripped of paint and rust steel radiators. Even better to connect this outlet with buried in the ground to a depth of 1-1,5 m with a metal object. It is desirable that in this location and at this depth the ground was wet.
The antenna should be placed as high as possible. For example, on the roof of the house. You can help & how shipping to get it on the high tree. In an extreme case, position it around the perimeter of the room in your residential home. However, in a reinforced concrete building such an antenna will not work. The antenna is a bare copper wire length of 15-20 m.
Tune in to the radio station by moving the ferrite rod inside the coil form. If you find that no radio station is not in the range settings, or faint on the edge of the range, make another coil, with large elementsin number of turns. Usually the coil can be from 60 to 220 turns.