spark gap transmitter

Discussion in 'General Electronics Chat' started by ttarique, Jun 10, 2013.

  1. ttarique

    Thread Starter New Member

    Jul 2, 2010
    9
    0
    Hello All:
    I am developing a spark gap transmitter. I have attached a picture. Can you guys tell me the capacitance values(C1,C2), voltage rating and inductance(L) values, please? Or give me an example. My frequency is 50Hz.
     
  2. MrChips

    Moderator

    Oct 2, 2009
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    I would think twice about testing a spark gap generator. They create a lot of RF noise that can disrupt other RF services.
     
  3. WBahn

    Moderator

    Mar 31, 2012
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    A second MrChips' comment. Depending on where you are, you can expect a visit from the authorities pretty quickly if you start playing around with a spark-gap transmitter.

    Aside from that, why are you trying to transmit at 50Hz? Your wavelength at that frequency is about 6,000 km.
     
  4. PackratKing

    Well-Known Member

    Jul 13, 2008
    850
    215
    On the line of advice from Mr Chips...

    When in Highschool, circa 1963 with my first "car" :p it needed a set of sparkplug cables...

    Not having a source of income to buy a proper set, I wired them up w/ #18 zip-cord. :eek:

    That setup screwed up commercial radio & TeeVee for miles... FCC was on me like a duck on a Junebug...:D They had NO sense of humor about it either, and I narrowly BS'd my way out of a nice hefty fine...
     
    Last edited: Jul 22, 2013
    Metalmann and shortbus like this.
  5. ttarique

    Thread Starter New Member

    Jul 2, 2010
    9
    0
    Alright, I will NOT be using the transmitter antenna. I just want to create spark gap and resonance. Do you have an idea, what values of resistor, capacitor and inductor to use at 50 Hz? Your help is appreciated.
     
  6. WBahn

    Moderator

    Mar 31, 2012
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    The spark gap itself will radiate, as will many of the wires in the device.
     
  7. JDT

    Well-Known Member

    Feb 12, 2009
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    You won't be radiating 50Hz of course. You will be radiating 100 pulses of wide-band radio-frequency noise per second.
     
  8. Dodgydave

    Distinguished Member

    Jun 22, 2012
    4,985
    745
    OK Marconi, but who are you going to communicate with?

    for C2 use 10uF and L1 use 1000mH (1H)

    for R1 use 330 ohms, C1 use 10uF

    and the best of luck...
     
  9. Mike33

    AAC Fanatic!

    Feb 4, 2005
    349
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    If you want to just 'test' the concept out, connect one end of a file to a 9V battery. Use the 'hot' end to stroke the file's teeth while sitting near a radio. you will hear 'hash' as the voltage jumps and is interrupted along its trip. It's just noise; it hasn't been useful for comms since about 1905! Without the correct conditioning, that signal is little more than an annoyance! And to broadcast above a certain power level (forget what it is) is an FCC violation, as pointed out...

    You can test your circuit but remove the antenna - you won't need it if you're near anything that can receive the noise pulses (radio, TV, computer speakers etc).
     
  10. Kermit2

    AAC Fanatic!

    Feb 5, 2010
    3,788
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    This idea may be from one found on the internet many years back. by using a tuned cavity and waveguide horn from a 'Radar gun', one supposedly could TRICK a highway patrol officers radar into believing you were either moving backwards, standing still, or traveling at hundreds of miles an hour depending on your speed and the repetition rate of the sparks.

    Knowing how doppler radar works, I can assure everyone that this would not work and if the equipment was found by the officer, one would probably not$ want$ to$ ever$ do$ it$ again$$$$.

    :)
     
  11. WBahn

    Moderator

    Mar 31, 2012
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    I'll have to try that! Sounds like a neat little demo for a Physics II or Electric Circuits I course.
     
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