Topband: Elevated Radial Efficiency - an inordinately long post

[Milt, N5IA]

----- Original Message ----- 
From: "W0UN -- John Brosnahan" <shr at swtexas.net>

> I am reluctant to characterize Dave's extensive results over many,
> many months of testing although I have visited with him and looked
> at his arrays.  The best I can do is to encourage him to make his
> tests public.  And I know that he is very happy with his choice and
> the performance of his two arrays.
>
> --John  W0UN
------------------------------------------------------------------------------------------------

----- Original Message ----- 
From: "William Culpepper" <culpepper at earthlink.net>
To: <Topband at contesting.com>
Sent: Wednesday, November 28, 2007 9:53 PM
Subject: Re: Topband: Elevated Radial Efficiency - an inordinately long post

> Do my measurements in the broadcast band mean that four elevated radials
> will work on 160 meters as well as 120 buried wires?  I have not proved
> it,
> but my opinion is that they will work very well.  But that is just my
> opinion.
>
> At the invitation of Tim Duffy (K3LR), I covered all of the above and much
> more in my talk at the Antenna Forum at the Dayton Hamfest in 1996.
>
> 73,
>
> William
> W4BZ
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Bill and John,

I have constructed three of the TX antennas for 160 Meters which have been
very similar to your description.  I call them elevated Ground Planes.

N5IA has a full quarterwave of Rohn 25 above an insulated base 1/8 WL above
AGL with four cage 1/4 WL radials sloping slightly downward to the tops of
55' woooden poles.  The cages are comprised of 4, # 14 copperweld wires in a
1 foot square pattern.  The antenna is series fed through a homebrew
toroidal transformer to match the 50 Ohm feedline to the measured base
impedance of 37 Ohms.  2:1 bandwidth is 180 kHz.

W7MCO has 80 feet of Rohn 25 above an insulated base 1/16 WL AGL with 15 1/4
WL radials sloping down to approximately 10' AGL.  Top loading of the 80' of
tower is done with a Force 12 C4XL and an additional 10' stinger to make it
resonate.  The antenna is series fed and the 2:1 bandwidth is 140 kHz.

At XZ0A in 2000 we installed 80' of Bangkok Rohn 25 knock-off tower above an
insulated base 40' AGL.  40' of telescoping mast was installed above the top
of the tower to resonate it at 1.828.  Twelve, 1/4 WL radials were
installed, sloping downward to near ground level.  The antenna was series
fed with more than 300 feet of RG8-X feedline.

All three installations and the operations from them have been WINNERS!!!!!!

73 de Milt, N5IA