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I work in a radio station situated on a hill top. The Earth resistance measured at this location is quite high, measuring around 9 Ω. There is no deep gorge nearby to make a fresh Earth Pit. How can I reduce the Earth resistance in my station?

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    \$\begingroup\$ @Andyaka Lightning is damaging my expensive eqpt. \$\endgroup\$
    – seccpur
    Sep 2, 2022 at 8:13
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    \$\begingroup\$ @seccpur... About the best you can do is dig out an area in which to lay down criss-crossed 1/2" rebar rods, tied together with ground-rod clamps like these -- not just wire-wrap, and poured over with a slab of concrete. Make sure one of the rebar rods is bent upwards and out of the concrete so you can clamp directly to it. You won't get better. It's called a Ufer ground after the professor who analyzed it. Resistance into Earth will be about as low as it can get. Do not use copper wire in the mix! \$\endgroup\$
    – jonk
    Sep 2, 2022 at 8:14
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    \$\begingroup\$ @DDuck Thanks. Agreed. The problem is that that OP has a separate question about lightning protection. The Ufer ground can only be one part of a well-designed system. I don't want to write an answer here knowing full well that the OP is also dealing with a serious problem regarding lightning strikes, as well. There's a full design required. And I'm not prepared for that. (For example, the rise time for the initial current can be as short as \$10\:\text{ns}\$! And any good design accounts for both inductance and resistance, as just one part of much else.) \$\endgroup\$
    – jonk
    Sep 2, 2022 at 9:18
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    \$\begingroup\$ @seccpur to measure resistance you need to have a reference point and a measurement point. What/where were those two points? \$\endgroup\$
    – Andy aka
    Sep 2, 2022 at 9:48
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    \$\begingroup\$ @seccpur In the meantime, have a look at this link regarding the Ufer ground. It is very much worth a read. I don't use wire-ties. Instead, I use something like these very cheap brass screw-ties to couple the rebar together. It's very tight, solid, and works very well. ( I get them for about US$1 each.) But use what you can. Regardless, the Ufer ground is the best you can get. \$\endgroup\$
    – jonk
    Sep 2, 2022 at 9:50

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There are a few ways that you can try to reduce the earth resistance at your radio station:

  1. Increase the size of your earth pit: A larger earth pit can provide a lower resistance path for electrical current to flow into the ground. You can try making your earth pit deeper or wider to increase its size.
  2. Use multiple earth pits: Instead of relying on a single earth pit, you can try using multiple earth pits spaced out around the radio station. This can help distribute the electrical current more evenly and reduce the overall resistance.
  3. Add electrolyte to your earth pit: Adding a conductive material such as saltwater or a proprietary electrolyte solution to your earth pit can help improve its conductivity and lower the resistance.
  4. Install earth rods: Earth rods are long metal rods that are driven into the ground and can provide an alternate path for electrical current to flow into the earth. You can try installing one or more earth rods at your radio station to help reduce the earth resistance.

It's worth noting that earth resistance can be affected by a number of factors, including the type and moisture content of the soil, the size and shape of the earth pit or earth rods, and the distance between the earth pit or earth rods and the electrical equipment. As such, it may take some experimentation to find the most effective solution for reducing the earth resistance at your radio station.

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