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Building a ~20khz Radio on the Cheap

  1. May 8, 2013 #1
    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.

    Thanks guys.
  2. jcsd
  3. May 8, 2013 #2


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    welcome to PF :)

    now assuming you didnt err on your frequency range, the only thing of interest in the 10 - 20kHz to listen to are Atmospherics .... Whistlers, Dawn Chorus etc

    google is a wonderful thing ;)


  4. May 9, 2013 #3


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    I think you need to indicate whether this is for AM or FM stations. :wink:

    What signal or waveform will you recover from each radio signal?
  5. May 9, 2013 #4
    I am trying to receive an audio signal within this range of baseband frequencies. I don't think it is AM or FM signals - these waves are longwave radio signals and fall beneath the range of AM frequencies (540 - 1710 khz). SO neither AM or FM.

    Specific instructions would be appreciated :).
  6. May 9, 2013 #5

    There are many many radio designs with many frequency ranges available at the site. Are you aiming for the aircraft band or some other particular type of frequency? The radio I just built was for trying to pick up Jupiter's emf so I can hear the "noises" theta net makes. I do not know if I was successful or not t it was interesting to listen to.

    Essentially an LM386 with a 1000microFarad cap to set the gain high so you can hear the faint signals being received by the antenna. That's the approach I used. If you have any questions concerning my build please send me a message and I will link you the schematic. However it is also available in the link I posted, just search for anything radio and you should run into something to fulfill your requirements. Hope this helps.
    Last edited: May 9, 2013
  7. May 9, 2013 #6


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    A specific requirement would be necessary before you can expect any specific instructions. You need to decide exactly what you want to do before you can obtain any real help here.
    FM and AM are forms of modulation and do not 'define' a frequency band, although certain bands tend to be used for particular purposes.
    What actual signal(s) do you want to receive and what actual frequency(ies)? Do you just want to detect an unmodulated Carrier Wave? Will these be high level or low level signals? What sort of antenna do you propose to use?
  8. May 9, 2013 #7


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    Did you even look in the link I gave you ???

    its exactly for receiving those frequencies

    But as others have asked and you still havent told us....

    Specifically what are you wanting to receive ?

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