# How do I build a radio that receives a ~20khz signal?

I am trying to build a radio to receive a 200 hz - 20 kHz signal. Can anyone give me a starting point as to what specific parts I would need (breadboard, operational amplifier, transistors, resistors, antennae, etc..)? The signal frequency is the most important thing for this project.

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• 7 years ago

Do a web search for homebrew VLF receiver. You'll see quite a few. No, you won't be building even a half-wave antenna. If you want some help, look for a local ham club. Use the reference to search for one.

• 8 years ago

Transceiving via a 200 Hz carrier, even a 20 KHz carrier is going to be pretty difficult.

Therefore, I'm going to assume that the 200 Hz to 20 KHz frequency range is the baseband frequency, that is, plain old audio.

The simplest would be to build an AM transmitter and receiver, where the transmitter carrier is amplitude-modulated. That is the easiest to de-modulate at the receiver.

As for parts, there are too many to list, and you also didn't say if you can use any chip-level devices (both Tx and Rx devices are available and require very few external components to create fully-functional transmitters and receivers), or if you want to try to build this using discrete components.

Yes, you'll need a breadboard of the type that allows you to easily plug in, move and remove parts and wires.

• 7 years ago

Your best bet is to look online for some circuit diagrams although their may not be any available as I remember wanting to do something similar for 10Hz. I've built a receiver that goes from 30KHz upwards but nothing lower then that. You'd also need a mighty huge antenna for that low frequency.

Its a very interesting project, they say that the human brain runs on 16Hz.

• Anonymous
8 years ago

only the military with special equipment and antenna farms many miles long can do the 200 Hz

do the wave length calculation C = L * F

when I was a kid ( back in the stone age) we made "crystal radios" with wrapped wire, and "cat's whisker" diode, and homemade or sore bought capacitors

people who do this are called "radio hams" and there are few still around

Source(s): Have fun you will learn a lot
• 4 years ago

hi Dimitar! sure they do, frequently lots to the unhappiness of the radio astronomers making use of the telescope who're attempting to %. up truly faint indicators from distant products in area. fortuitously, they might frequently clear out maximum of those stray indicators out. :)

• 8 years ago

To receive a 20kHz signal efficeintly you'd need a dipole antenna 15km long.

For 200Hz, 1500km long

• 7 years ago

most important are the antenna and the capacitor which works in conjunction with it... These should be tuned to this frequency.

Source(s): electronics