RF Oscillator from scratch

Discussion in 'The Projects Forum' started by hersheybenjamin, Dec 23, 2010.

  1. hersheybenjamin

    Thread Starter New Member

    Dec 23, 2010
    I am seeking to make an FM transmitter totally from scratch. By "from scratch", I mean not using any pre-made circuits or any doped semiconductors. I just want to use wire, batteries, etc. So basically my question is: Is it possible to make a sine wave oscillator without the use of any transistors or amplifiers? Capacitors, inductors, etc. are no problem, but I can't make doped silicon from scratch. So the oscillator would not be able to include: transistors, amplifiers, diodes, inverters, etc. Is this possible? Any help would be greatly appreciated. :) Thanks!
  2. Wendy


    Mar 24, 2008
    You could, but it would not be legal. You have entered the realm of arc gap transmitters, where an arc across a tank circuit generates RF.

    As for modulation, forget it. This type of generator (it is not an oscillator strictly speaking) splatters all over the spectrum.

    For clean signals, an active device is required.
  3. DickCappels


    Aug 21, 2008
    Then you might want to make your own zinc negative resistance diode, which is a home made semiconductor that can be used to make an oscillator. This can probably get you up to several MHz, though you might get lucky and make a VHF device.

    This link takes you to a demonstration of such a transmitter:

    This link tells you how to make your own diode out of sheet metal and shows some application circuits:

    This link contains a video showing a negative resistance diode being made and an 80 meter transmitter circuit:

    Here is the web page for that 80 meter transmitter:
    Last edited: Dec 23, 2010