Thank you for asking this, because I have always been fascinated with the
concept of loaded Beverages (either BOGs or shortened overhead).
But what did you mean by "proper pattern"? I assume that you mean "usable
pattern" and that realize that the pattern will change with frequency. See
for yourself at
www.w0btu.com/Beverage_antennas.html#Beverage_antenna_freq_range
To me, those patterns are all "proper" and very "usable" much of the time.
Although I have EZNEC+ 5.0, I have no experience with Beverage models with
lumped loading. Hopefully, somebody reading this will.
73, Mike
www.w0btu.com
www.w0btu.com/Beverage_antennas.html
On Fri, Aug 23, 2019, 1:40 PM Mikek <amdx@knology.net> wrote:
> I want a BOG that will have a proper pattern over 500kHz to 4Mhz.
> As I understand it, "loaded Beverages show increased directivity because
> velocity of propagation along the antenna is /*decreased*/."
>
> I assume that is for antennas that are shorter than what is required for
> that frequency.
>
> Info from here, https://www.w8ji.com/slinky_and_loaded_beverages.htm
>
>
> Is there any reason I can't load a BOG to make it directive at 500kHz?
> My BOG length limit is 250ft. Assuming the answer is yes.
>
> If I do add the proper inductances along the length of the antenna then at
> 4MHz the pattern suffers. (previously I used nine inductors) The inductance
> must be reduced as frequency goes up.
>
> To that end I'm searching for a specific ferrite core geometry, like this,
> https://www.dropbox.com/s/2bwsxrc58g51yu8/E%20Core%20Ferrire%20DB.jpg?dl=0
> Note, I dropped this and chipped the important part in the center, but
> before that, it did what I wanted.
> This material was not good at the frequencies I'm interested in.
> So I need a material good to at least 4MHs and with an AsubL of 2000 to
> 3000, or more, with a similar
> geometry. Or any geometry that necks down to a smaller cross section.
>
> Where can I buy such a core?
>
> Thanks, Mikek
>
PS, if anyone here wants to model a 250ft bogit over that frequency
> range, you would have my undying gratitude.
>
>
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