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Good Evening Tom.

Here is one of them

? This is an open wire loop with no shielding for obvious?reasons because of its physical?size.

Here is another VLF antenna using a Ferrite Rod

There was a third one I recently found but can't seem to locate it at the moment.? The one with the ferrite rod ought to give you some idea of the shielding and I hope the reason for the shielding. Basically the shield reduces the electrical field and lets the magnetic field in the box.? When I find it I will?pass it along.

Fred

N4cla

On Tue, Feb 11, 2025 at 8:49?PM Tom ANderson via <SDR_Radio=[email protected]> wrote:

Fred,

Can you list the web sites that talk about this type of antenna?? I have never heard of the gap that you mention nor the shielding.

I am familiar with loop antenna but this seems very different then a normal loop?

Thank you

Tom

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?

Tom Anderson

SDR_Radio@...

On Feb 12, 2025, at 2:13?AM, Fred Moore via <n40cla=[email protected]> wrote:

?

I am thinking of making a VLF loop out of a 10 ft piece of PEX pipe with many turns of wire inside the PEX and a plastic junction box on the bottom.? I have read several articles about doing the same thing with copper pipe as the shield and making a gap in the top center of the pipe. The purpose of the gap is to shield the windings from electrical noise and allowing the magnetic waves inside the pipe.?

There are several?articles on how to shield VLF antennas ie; Ferrite Rods, from electrical noise.? Making copper pipe loops and metal electrical boxes at the bottom and cutting a gap in the pipe at the top is basically the same as shielding the Ferrite Rod with aluminum and leaving an air gap for the magnetic waves.? Pex is a different animal as if you cut a gap in the top of a PEX loop, you lose the round loop. So my question is this.? What if I keep the round loop attached to the plastic electrical box and shield the entire round loop with #80 copper mesh and not the box, would I have the same shielding as an the copper pipe loop?

Fred

N4CLA