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Thread: Question about lightning ground.

  1. #1

    Default Question about lightning ground.

    I'm going to be setting up my antenna mast this weekend, weather willing. I settled on a 40 foot aluminum mast, 30 feet or so of which will be above the second floor roof level.

    My question is, can I just ground the base of the mast, or should I ground up at the antenna itself?

    My plan is to use 8 gauge copper wire and go straight to an 8 foot grounding stake. Should that be sufficient?

  2. #2

    Join Date
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    Provided that there aren't any large non-conductive sections, then just the base will do.

  3. #3

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    It would be a good idea to invest in a lightning arrestor for the coax line as well.

    Not sure the antenna you plan to use but I will use my Sirio 827 as an example.... On my antenna there is a loading coil at the base. Although the tip of the antenna is at DC ground due to this coil, the turns of the coil are so tight (2 inch diameter maybe) that if lightning were to strike it, the magnetic field caused by the current of the strike would blow the coil apart. The instant that happens, the rest of the juice will follow the coax indoors and into your radio.

  4. #4

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    "Lightning protectors" are really misnamed. If your mast gets hit by lightning, then that's it, it's "Game over, man!". Their proper name is surge or overvoltage protectors.
    Ground your mast by all means, that should reduce the risk of static build up on the mast during a storm, but that is it. In the event of a storm being overhead, or very close by, your best bet is to unplug every electronic device in the house from both the mains supply and any aerials. If you can't put the coax plugs outside, then I have heard people put them into glass jars.
    I use this website: blitzortung.org to see how far away the strikes are. If it's within a few km of home, we unplug everything.

  5. #5

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    I've never had the misfortune of testing the theory, but I agree with OH8GAD. I've always had the idea that most of the power would still jump straight to ground and what went into the coax would be a mere fraction of the energy, but yea, perhaps its false hope. I unplug as well.

    lightningmaps.org is the site I use. It shows the propagation of the sound wave too, kinda cool.

    EDIT: the website above, upon further research, gathers some of its information from the site OH8GAD listed.
    Last edited by brandon lind; Sun 2nd Dec 2018 at 19:26.

  6. #6

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    I lost an Icom 756 Pro III and an alpha amp to lightning...I did unplug the antenna coax but forgot to unplug the power... surge through the main power line got them both... along with a few other things in the house...grounding well will help, but not prevent the issue.

  7. #7

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    What exactly is a glass jar supposed to do with lightning? Become shard material when it explodes?

  8. #8

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    glass is supposed to be an insulator. Years ago I brought all my coax runs to one board on the back of my bench. I used thru the wall coax connectors and drilled holes in jar lids and put them on the connectors... in storms I would drop the jumpers from my rigs and screw jars onto the lids....never had the misfortune of seeing if they helped or not...an effort I am glad never paid off....or failed.

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