Lightning - sferics detectors

Discussion in 'Homebrew and Kit Projects' started by N8YX, Aug 6, 2008.

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  1. KL7AJ

    KL7AJ Ham Member QRZ Page

    Yip....quite a few of us interested. I have a chapter in the Opus on natural radio, as well. Good work!

  2. AB8RO

    AB8RO Ham Member QRZ Page

    Ok, here are a few more measurements of the computer power supply inductor. If you take the two inductors in phase in series you get about 30mh. Out of phase, or shorting the second winding you get only about 100 microhenries.
    Last edited: Aug 7, 2008
  3. ZL3GSL

    ZL3GSL Ham Member QRZ Page

    The compact fluorescent lamp bases I have dismantled have all had a nice little choke marked 4.5 mH as the ballast for the tube. A couple of those in series would probably be close enough. There might be a particular tube size with a 10mH ballast. (That would probably be about 5W if such a size is made.)
  4. AB8RO

    AB8RO Ham Member QRZ Page

    I wouldn't have thought to take those apart, that's good information. I also just noticed that it's not two 10mH but a 10mH and a 1 mH inductor. So I think that the 8 mH computer inductor will work just fine. 1mH inductors are far more common.
  5. ZL3GSL

    ZL3GSL Ham Member QRZ Page

    There are a few "good bits" in those units, including a little toroid which drives the two TO92 transistors in antiphase. I haven't checked further, so I "think" the diodes are just conventional 1N4007s, not Shottky ... but some of them might be. The frequency seems to be about 40 kHz, but of course they don't need fast diodes, because the tube is run on that AC.
  6. KA5ROW

    KA5ROW Ham Member QRZ Page

    TV lightning Decatur

    :D You can use a old TV, tune it to CH 2 and on the snowy screen lightning will make horizontal lines across the screen. The closer the storms gets the wider the black horizontal lines get. This has been known sense the 1950's. :D

    So in February 2009 sell them on e-Bay as a lightning Decatur. As the new Digital TV's give up that feature
  7. N8YX

    N8YX Ham Member QRZ Page

    ...but none of that pertains to "Homebrew", which is what this forum is all about.

    I'll play along and open a discussion, however:

    Today's analog TV sets are far less capable of serving as a "detector" than those used in the 1950s, when the phenomenon was first discovered. Explain why.

    Extra points awarded for describing the mechanism whereby a tornado or energetic mesocyclone generates RF energy, and the characteristics of that energy. The data is very germaine to the project contained in this thread.
    Last edited: Aug 7, 2008
  8. N0WVA

    N0WVA Ham Member QRZ Page

    I think some of the new analog tv's screens go blue when there is no signal. So you wouldnt see any static.

    Id say that the RF energy from the tornado is produced by the dust in the air making static electricity.
  9. W0LPQ

    W0LPQ Ham Member QRZ Page

    5ROW says ... "So in February 2009 sell them on e-Bay as a lightning Decatur." Hey Fred (YX), is this like the Decataur in Illinois?? They may have some analogs over there!!
  10. AB8RO

    AB8RO Ham Member QRZ Page


    Here's a schematic of a commercial detector. The text states that a tuned circuit on the input isn't necessary.

    I'm not sure why there's a note in the schematic "not to build" the circuit, but, in any case, it's not as straightforward as the above circuits.
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