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Re: [TowerTalk] Press release Re: F12 ants !!

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Subject: Re: [TowerTalk] Press release Re: F12 ants !!
From: Wes Stewart <wes_n7ws@triconet.org>
Date: Thu, 11 May 2017 10:53:47 -0700
List-post: <towertalk@contesting.com">mailto:towertalk@contesting.com>
So they take a Force 12 model, change everything about it and still call it a Force 12?

Wes  N7WS

On 5/11/2017 9:54 AM, Jim Thomson wrote:
## Apparently,  JK antennas in CT,  will be building some select models of 
legacy F12 ants, yagis + verts.
But  each select  F12 ant will  be completely re-optimized to  NEC-4 pro 
standards.   EG, F12s  5BA has been
re-designed, with fewer eles, and more gain, better performance.  They will 
also be  completely
re-designed  mechanically  to  JK antenna  standards.

##    F12 used the now obsolete  RS-222-C method for determining wind loading.
The problem with the 222-C spec is the effective area was used, instead of the 
actual projected area
of a cylinder.   IE, what F12 called  6.67 sq feet is actually 10 square feet.  
 You have to take the
old F12 square footage..and multiply by 1.5   to get reality.
The calculated V max, using 222-C is incorrect.  Ken Garg at JK antennas uses 
the newer standard,
as in what you actually measure inside a wind tunnel.   Mosely, Hy-gain, M2 are 
still using the old 222-C spec.
100 mph using the wind tunnel spec, = aprx  112 mph using the old 222-C spec.
100 mph using the 222-C spec is in reality, aprx 92 mph using the new spec.

##  new versions are built a lot stronger, handle ice loading,  and a real 
100++ mph wind, etc.
The re-designed select F12 ants will augment the superb, existing line up of JK 
ants.

https://jkantennas.com/news.html

Jim  VE7RF
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