It isn't the feedpoint impedance that matters, it is the antenna radiation
resistance that matters. For example, if we take a quarter wavelength
vertical having radiation resistance of 36 ohms and add a wire to make it a
folded vertical having input impedance of 144 ohms it still has a radiation
resistance of 36 ohms. The ground loss eats up the same amount of RF energy.
To increase the radiation resistance the current-area must be increased.
Two ways to do that are to lengthen the antenna (up to 1/4 wavelength) or
top load it. On 60 meters1 the HF2V is a 32' base loaded vertical having a
radiation resistance of ~1.5 ohms. Top loaded this can be increased to ~5.5
ohms, potentially increasing your signal by almost 6 dB. The HF2V manual
mentions top loading on page 11.
*HF2V manual*
https://static.dxengineering.com/global/images/instructions/but-hf2v_ck.pdf
Dave KH6AQ
On Wed, Mar 10, 2021 at 3:07 AM Richard Quick <rich.w4rq@gmail.com> wrote:
> I have as much of a compromised antenna for 160 as you can get.
> A Butternut HF2V with a 160 coil, mounted on a chain link fence.
> I have a small lot with overhead power lines across the back of the
> property, and Am looking for a better idea.
> I’m thinking a hi impedance feed point antenna ie:450 ohms would require a
> much less extensive ground radial system than say, an inverted L with low
> impedance. Easier to match a 450 Ground than 37 ohms.
> Am I nuts? Anyone with ideas along this line of thinking?
>
>
>
> Rich - W4RQ Amateur Radio: The Original Social Media
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