Topband: Measure dipole on ground to get VF of BOG.

[VE6WZ_Steve]

Mikek,

I made a number of measurements of my Beverages last summer including using TDR to estimate physical length.  This depends on knowing the VF of the wire.  However, If you know the physical length length, the using the TDR function you should be able to derive the VF of the BOG.

Here is a YouTube video that shows the method I used and the results:
https://youtu.be/yiFW_u1CPrs <https://youtu.be/yiFW_u1CPrs>

73, de steve ve6wz


> On May 2, 2020, at 11:22 AM, Mikek <amdx at knology.net> wrote:
> 
> I'm about to do some measurements on a BOG.
>  I've been a little slow getting things working, I've now got my inside and outside boxes assembled,
> I understand I can break the BOG in the middle and find resonant frequency as a dipole.
> From that I can calculate the VF. I may leave this for a while and hope for rain to get some
> different measurements.
>  I also wonder about measurements, on the ground, at 1" above ground, and at 2" above ground. Is there any advantage to
> the pattern or signal strength. At 2" inches I could weed whip to keep it weed free.
> 
> 
>  On a second note, I'm building it long, for the AM band and considering using KD4Zs stretch modules (in my case shrink modules)
>  for 160M and 80M bands. Although I think I would just terminate instead of reflect.
> 
>  Your thoughts? any good pages about the Dipole on ground measurements appreciated.
> 
>                             Mikek   KF4ITA
> 
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