How to hear electromagnetic waves
Good afternoon, dear habrovchane.
In this post I will tell you an unusual method by which you can convert invisible electromagnetic waves into an audible sound range, which will allow you not only to hear radio waves, but also to determine their power, type and direction.
I took the cassette player as a basis. It has a head that converts magnetic waves from a tape into electrical voltage audio voltage. The head is a coil inductance, loaded on a sensitive playback amplifier and due to this well captures electromagnetic waves. But the manufacturer made sure that there was no unnecessary interference and well shielded the head. Therefore, you need to disassemble the player and disconnect the shield wire from the head. Everything! Now the head has turned into an antenna. In order for the player not to catch its own waves, you still need to disconnect the motor of the tape drive mechanism and power it necessarily from the batteries, otherwise the background of the 220V network will be heard. 50 Hz. Interestingly, the amplifier of the player, 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 catches even very weak electromagnetic waves. I managed to hear the waves from the remote control and from the wristwatch.
It turned out that almost all consumer electronics emit electromagnetic waves. You can determine the radiation power, focusing on the volume of sound and range. Although the player picks up waves from all sources simultaneously, by the nature of the sound, it is easy to understand from which source the waves are the strongest.
Below I give a list of various wave sources, the maximum range at which the player picks them up and describe the sound they create:
1 - range, 2 - source of radiation, 3 - what sound is like
2 mm - TV remote control - melodic, rhythmic
1 cm - charger from a mobile phone - squeak with crackling
15 cm - laptop - hiss, buzz
2 meters - wi-fi router - rustle
3 meters - mobile phone when you call - rhythmic buzz
1 km - mobile base station - melodic sound, like a flute, each BS has its own
2 km - TV tower - crackling with a changing whistle when the picture on the screen changes
Although this method can not measure the level of electromagnetic radiation, it is possible to approximately estimate how strong the background is in your apartment. At my home, with the technology turned off, the background is so small that the player does not fix it. But on the street already a little picks up the radiation of the nearest BS mobile communication. 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 is buzzing so much that you can not hear the radiation next to the working phone! Watch the video where I rode through different streets and listened to the electromagnetic background:
In this post I will tell you an unusual method by which you can convert invisible electromagnetic waves into an audible sound range, which will allow you not only to hear radio waves, but also to determine their power, type and direction.
Principle of operation
I took the cassette player as a basis. It has a head that converts magnetic waves from a tape into electrical voltage audio voltage. The head is a coil inductance, loaded on a sensitive playback amplifier and due to this well captures electromagnetic waves. But the manufacturer made sure that there was no unnecessary interference and well shielded the head. Therefore, you need to disassemble the player and disconnect the shield wire from the head. Everything! Now the head has turned into an antenna. In order for the player not to catch its own waves, you still need to disconnect the motor of the tape drive mechanism and power it necessarily from the batteries, otherwise the background of the 220V network will be heard. 50 Hz. Interestingly, the amplifier of the player, 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 catches even very weak electromagnetic waves. I managed to hear the waves from the remote control and from the wristwatch.
We listen to radio waves at home
It turned out that almost all consumer electronics emit electromagnetic waves. You can determine the radiation power, focusing on the volume of sound and range. Although the player picks up waves from all sources simultaneously, by the nature of the sound, it is easy to understand from which source the waves are the strongest.
Examples
Below I give a list of various wave sources, the maximum range at which the player picks them up and describe the sound they create:
1 - range, 2 - source of radiation, 3 - what sound is like
2 mm - TV remote control - melodic, rhythmic
1 cm - charger from a mobile phone - squeak with crackling
15 cm - laptop - hiss, buzz
2 meters - wi-fi router - rustle
3 meters - mobile phone when you call - rhythmic buzz
1 km - mobile base station - melodic sound, like a flute, each BS has its own
2 km - TV tower - crackling with a changing whistle when the picture on the screen changes
Opportunities
Although this method can not measure the level of electromagnetic radiation, it is possible to approximately estimate how strong the background is in your apartment. At my home, with the technology turned off, the background is so small that the player does not fix it. But on the street already a little picks up the radiation of the nearest BS mobile communication. 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 is buzzing so much that you can not hear the radiation next to the working phone! Watch the video where I rode through different streets and listened to the electromagnetic background:
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Source: https://habr.com/ru/post/228729/
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