How to hear electromagnetic waves

  • Tutorial
Good afternoon, dear Khabrovites.
In this post, I will tell you an unusual method with which you can convert invisible electromagnetic waves into an audible sound range, which will not only hear radio waves, but also determine their power, type and direction.

Principle of operation

As a basis, I took a cassette player. It has a head that converts magnetic waves from the tape into electrical voltage of sound frequency. The head is an inductor loaded on a sensitive playback amplifier and, due to this, picks up electromagnetic waves well. But the manufacturer took care that there were no unnecessary interference and well shielded the head. Therefore, you need to disassemble the player and disconnect the shield wire from the head. All! Now the head has turned into an antenna. So that the player does not pick up its own waves, you still need to disconnect the tape drive motor and be sure to feed it from the batteries, otherwise the 220 V network background will be heard. 50 Hz. It is interesting that the player’s amplifier, in this mode, not only amplifies the signal, but also acts as an amplitude detector. As a result, you can hear the electromagnetic waves of the entire radio range: from 20 Hz to 50 GHz. The player easily picks up even very weak electromagnetic waves. I managed to hear the waves from the remote control and from the wristwatch.

Listen to the radio waves at home

It turned out that almost all consumer electronics emit electromagnetic waves. You can determine the radiation power, being guided by the volume of sound and the propagation range. Although the player picks up waves at the same time from all sources, by the nature of the sound you can easily understand from which source the waves are the strongest.


Below I give a list of different wave sources, the maximum range at which the player picks them up and describe the sound that they create:
1 - range, 2 - radiation source, 3 - what the
2 mm sound looks like - the TV remote is melodic, rhythmic
1 cm - charging from a mobile phone - squeaking crackling
15 cm - laptop - hissing,
2 meter buzzing - wi-fi router -
3 meter rustling - mobile phone on call -
1 km rhythmic buzz - mobile communication base station - melodious sound, like a flute, each BS a
2 km - TV tower crackling with whistle-changing when you change the image on the screen


Although this method cannot measure the level of electromagnetic radiation, you can roughly estimate how strong the background is in your apartment. At home, with the technology turned off, the background is so small that the player does not fix it. But on the street it is already picking up radiation from the nearest BS mobile communications. My friends, in a city apartment, the player captures a stable and fairly strong background, especially near the windows. But in some places in the city, the background is very strong. The player buzzes so hard that you can not hear the radiation next to the working phone! Watch the video where I drove through different streets and listened to the electromagnetic background:

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