[TowerTalk] Modeling Rohn 25G in K6STI's AO

[Mark - N5OT]

Gawd I got so educated over the weekend.  That was great.

I put up 50 feet of tower, a 12 foot mast, and two 70' long top load 
wires.  Tuned out the SWR at the shack with a matching network.  
Stations heard me well, I thought.  Worked Great Britain from Oklahoma, 
etc.  More data for the cruncher.

I still think traps are elegant, but the most practical solution at N5OT 
is to keep it simple and put up a different vertical for 80 meters in 
another part of the yard.

Thanks everybody for all the great comments.

73 - Mark N5OT


On 10/24/2021 1:50 PM, Dan Maguire wrote:
> Hi Mark,
>
> Those models are some of the most complex I've ever created. I'm not 
> sure I could do it again if my life depended on it!
>
> Dan
> On Sunday, October 24, 2021, 04:38:31 AM PDT, Mark - N5OT 
> <r-emails at n5ot.com> wrote:
>
>
> Thanks, Dan.  I got buried in your content for about an hour and it 
> was excellent.
>
> Mark
>
> On 10/23/2021 9:38 PM, Dan Maguire wrote:
>> Jim Brown wrote:
>>>>> I've seen a simple equation for modeling a straight triangular tower in NEC. As I recall, the diameter worked out to be around 0.65 the width of a side. This would account for modeling it as a radiator.
>> The image just below "Wire Geometry" on pagehttps://ac6la.com/aecollection8.html  <https://ac6la.com/aecollection8.html>shows the equivalent diameter for Rohn 25G according to:a) Section 9.1 of Leeson's "Physical Design of Yagi Antennas"   EquivDia = SQRT(Area / PI) + Perimeter / (2*PI) = 9.55 inchesb) Wikipedia pagehttps://en.wikipedia.org/wiki/Antenna_equivalent_radius  <https://en.wikipedia.org/wiki/Antenna_equivalent_radius>    EquivDia = 2 * (LegDia/2 * FaceWidth^2)^(1/3) = 8.58 inchesI'm afraid I don't know which is "more correct".Dan, AC6LA______________________________________________________________________________________________TowerTalk mailing listTowerTalk at contesting.com  <mailto:TowerTalk at contesting.com>http://lists.contesting.com/mailman/listinfo/towertalk  <http://lists.contesting.com/mailman/listinfo/towertalk>
>