During the Second World War, soldiers in Europe used the so-called “trench radio”.The radio received this name because of its simplicity of manufacture and soldiers were forbidden to use radios such as a superheterodyne or regenerator, they had a generator that could be detected by opponents.Trench radio is an ordinary detector radio, only instead of a diode, a homemade diode based on a razor blade serves as a contact, and a pencil lead serves as a contact and it does not emit anything.
You can make this radio yourself.To do this, an inductor is needed, I applied inductance to short waves and the coil contains 15 turns of wire with a diameter of 0.5 mm wound on a frame with a diameter of 20mm.A ferrite rod is inserted into the frame, it can be used to make a small adjustment on the radio station and reception will be better with it.The receiver output is connected to the input of a low frequency amplifier.
Take the blade and heat one side, an oxide film will appear on the other side.In this film, it is necessary to touch a pencil with a pencil point and focus on the best signal of the radio station, although the oxide film is already on the blade itself and you can not even burn it.The most important thing in such radios is the antenna, because this radio does not require a traditional power source, it is powered only by the energy of radio waves.The antenna is a wire 15 meters long, the longer the wire the better.I dropped this wire from a height of 10 floors down from the balcony and in the evening I caught two signals of radio stations, one of them very loud was the signal of Radio China.The longer the antenna and the higher it will be located from the ground, the louder the reception and more radio stations can be received.A ground connection can be connected to the receiver for even better reception.
