Re: [SPAM]Re: [CrossCountryWireless] Antenna Isolator install

Chris Moulding

The antenna and loop counterpoises are isolated from ground. The wire in the loop counterpoises is insulated and is laid directly on the ground to couple capacitively to ground.

The existing ground radial system was removed and replaced with the loop counterpoises.

If you were to use or follow the transformer design with the capacitors to counteract leakage inductance in the transformer it has an excellent match to 50 ohms so would work with the matching stub on your feeder. If you have already spent a lot of time optimising the tuning of a multiband vertical the transformer can be connected in circuit with very little difference needed to the antenna tuning. There were no changes needed on the two antennas I built to test the design.



On 19 Sep 2020, at 11:25, Will Grocott <wjcgrocott@...> wrote:

I’ve just read the article Chris, very interesting. I have a ground mounted Butternut with a radial plate and wire radials like you describe in your article, I have tried many things to reduce the noise on 20/30/40/80m but without much success. I’m sure most of this is being coupled into my current ground system from the local houses.

I have a 10x10m garden so I might experiment with some loops of different sizes. A couple of questions:

1) Did you completely disconnect the ground radial system and replace it with the loop(s)?
2) The Butternut has a matching stub for 20m in the feedline back to the shack, I’m not sure if this would now work as it is isolated from the ground side of the antenna...

I like the isolation and protection on the ground side. I will need to give this a bit more thought as to how I could try it with my current installation. 

Thanks again for sharing your ideas. Great work

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