Lightning - sferics detectors

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

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  1. N8YX

    N8YX Ham Member QRZ Page

  2. N0WVA

    N0WVA Ham Member QRZ Page

    You know, this would be a good first project for someone getting started in homebrewing.
  3. AB8RO

    AB8RO Ham Member QRZ Page

    You can get everything at radio shack except for the inductors. Any ideas on an easy way to construct 10mH inductors from commonly available materials? Ideally, that would not involve toroids because they aren't always easy to find.
  4. N0WVA

    N0WVA Ham Member QRZ Page

    Hmmm, thats a lot of windings, toroid or not. Then you have to come up with the small wire,too. First thought says get one from Mouser, but then that doesnt hold to the "all RS" parts.
    Then again, do they still carry meters?

    Is there a way to make a low-pass filter at this low frequency from RC combinations? And what frequency should be the cut-off? Well below the BCB I suppose.
  5. KB9BVN

    KB9BVN Ham Member QRZ Page

    Neat project. Mouser has the 10mH and 1mH inductors. About $4 each shipping...egads.
  6. AB8RO

    AB8RO Ham Member QRZ Page

    My thoughts exactly. Surely there's a better way than that? What types of cores could one use to make it practical? There was an interesting discussion about a similar issue on one of the Indian ham web sites where they used, I believe, brass, don't quote me on it, cores to avoid the high cost and low availability of toroid cores.
    Last edited: Aug 6, 2008
  7. AB1GA

    AB1GA Ham Member QRZ Page

    Well, if I had to scrounge something I'd first get the antenna core from an old AM radio, which should work at the frequencies lightining detectors use.

    Then you'd need some wire. Since it's a receiver, size isn't important, so just about anything would do, like the winding from an old transformer from a wall wart. As you wrap the coil, put a sheet of paper between layers so you that if the insulation is bad in a couple of spots you just short out a turn instead of a whole layer.
  8. AB8RO

    AB8RO Ham Member QRZ Page

    I have about a half dozen AM loop antennas and they are all in the 500 microhenry range. Of course you could change the cap to compensate. Perhaps someone would like to comment on what effects the shift away from a high L to C ratio would have?
  9. AB1GA

    AB1GA Ham Member QRZ Page

    More Wire!

    Or another junk coil. How about a deflection coil from a dead TV?
  10. AB8RO

    AB8RO Ham Member QRZ Page

    That's the right idea, what can be pulled. Here's something that I think will work. I pulled this choke from the AC input of a computer power supply. It's a dual choke, but I don't know if you could use both halves or you would need two of them. It seems that there must be some coupling.

    At any rate, it's about 8 mh. Close enough to make it work.
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