TopBand: Elevated GP vs. Vertical Antennas

[Eric Gustafson Courtesy Account]

>From: km1h@juno.com (km1h @ juno.com)
>Date: Sat, 21 Mar 1998 18:04:20 EST
>

Snip...


>>>I have a very simple question: With my soil AND terrain, what is
>>>the lowest TOA I can expect......with any # of radials?  I
>>>suspect it is around 15 degrees or higher...per ON4UN and the
>>>ARRL ANtenna Manual.
>>>
>>
>>I think I have enough info about your setup now to make a stab at
>>a reasonable estimate of this for you.  I'll probably get time to
>>do the work by next week sometime.
>
>Mucho Gratias!
>

I think I misread your post describing your system.  I just
couldn't get it working as I modeled it.  I'll adjust the model
and do it again. From your post, I thought the spacings you were
calling out were from the central support structure.  Now that I
see what that produces, I believe you must have meant that the
spacings were relative to the radiators.  So tell me if I am
correct now.  The radiator feedpoints are 65 feet from the tower
and the tops are 25 feet from the tower???

The single vertical over 6 elevated radials over the 1 mS ground
you called out results in a TOA of 27 to 30 degrees or so.  I'll
let you know what the array produces when I get its model
running.


Snip...


>>The radials didn't really add much effect for most of the
>>antenna work I was involved in (mostly because of the
>>wavelengths involved).  But the mesh was quite effective indeed.
>
>Very interesting observation Eric.
>

Not very mysterious.  The antenna size and the wavelengths I was
working with at that time resulted in the grid screen being much
larger than the near field zone.  Usually even large enough to be
effective in the far field zone as well.  The radial extensions
were too far away and too far apart to have any large effect.

Snip...


>
>A few dB is what this has been all about!  Do I get those dB by
>pure sweat or should I sucumb to the QRO malise that is becoming
>too darn evident?
>

No.  Make the antenna effecient first and _then_ go buy the four
holer...  ;-)

Snip...



>That is a great way to pick up 16' Eric....simple enough to even
>add more wires in that area. Is the 50' plus 16' a coincidence or
>does the now 1/8 wave of 66' have any significance?
>

Coincidence.

73, Eric  N7CL

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