How would you make a postage stamp size AM transmitter ?

Discussion in 'Wireless & RF Design' started by Externet, Dec 16, 2017.

  1. Externet

    Thread Starter AAC Fanatic!

    Nov 29, 2005
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    Hi.
    Say a monolithic oscillator, integrator to make it sinewave, and final amplifier transistor/IC...
    Aiming for VLF 100KHz RF TX, voice modulated, less than 100mW.

    What dedicated or convenient integrated circuits in the market could be used ?

    [​IMG]
     
    Last edited: Dec 16, 2017
  2. bertus

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  3. joeyd999

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  4. LesJones

    Well-Known Member

    Jan 8, 2017
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    Your biggest problem transmitting on that frequency is the antenna as the wavelength is 3000 metres. Also you will probably not be able to obtain a licence to transmit on that frequency.


    Les.
     
  5. Externet

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  6. philba

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    Aug 17, 2017
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    I'm not up on the current rules but isn't it legal under a certain output power and antenna limits. 100 mW runs in my mind but I'm sure that is wrong.

    As for license, I would absolutely worry about it as the FCC is quite zealous about enforcing the rules and Ham radio guys are very much a part of that.
     
    Last edited: Dec 17, 2017
  7. WBahn

    Moderator

    Mar 31, 2012
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    What makes you believe that that coil resonates at 100 kHz?

    Even if it does, using a coil like that for receiving from a high-powered transmitter is very different than transmitting using such an antenna.

    Are you saying that you don't care whether what you are trying to do is legal or not?
     
  8. Externet

    Thread Starter AAC Fanatic!

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    Thanks, gentlemen.
    To be exact, will be at 136 KHz, and I do have two licenses, so I do not care. That type of coil with a proper capacitor for resonance should work for a few metres. But a 10cm rod is in plans. Just showing a sub-stamp sized rod.
     
    DickCappels likes this.
  9. #12

    Expert

    Nov 30, 2010
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    Will the lawyer in this Thread please offer a reference for the FCC regulation concerning a 136 KHz transmitter with an effective range of 10 feet +/- 50%
    And then tell me how the FCC gets their scofflaw truck within 10 feet of the offending transmitter.:D
     
    cmartinez likes this.
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