Re: NEC-LIST:Simulations of Q and the Chiu-Harrington Limit

At 7:55 AM -0500 11/27/02, Fractenna_at_aol.com wrote:
>...If you are aware of simulations that beat Ed Altshuler's
>[Transactions Mar 2002] 5 wire...I would appreciate a citation or
>information before
>publication (which will, of course be properly attributed).

I don't remember anything about his five-wire antenna, but here is a
seven-wire model that beats the "optimized" seven-wire antenna
presented in his Transactions paper, with all the same constraints,
of course. The Q of my model is 15% lower (better) than the Q of his.

Here are the key lines of the NEC-4D input file for my model. I do
not claim that this model is optimal, as should be obvious from the
fact that the numerical values of its wire-end coordinates are round
numbers. Just that it's 15% better than Altshuler's.

CM Better seven-wire model fitting within cube of h/lambda = 0.045
CM on PEC ground-plane.
CM ITG NS XW1 YW1 ZW1 XW2 YW2 ZW2 RAD
GW 0 6 0. 0. 0. 0.0333 0. 0.020 0.0008
GW 1 4 0.0333 0. 0.020 0.0333 0.0333 0.020 0.0008
GW 2 4 0.0333 0.0333 0.020 0. 0.0333 0.025 0.0008
GW 3 4 0. 0.0333 0.025 0. 0. 0.0333 0.0008
GW 4 4 0. 0. 0.0333 0.0333 0. 0.0333 0.0008
GW 5 4 0.0333 0. 0.0333 0.0333 0.0333 0.0333 0.0008
GW 7 3 0.0333 0.0333 0.0333 0.0083 0.0333 0.0333 0.0008
GW 7 1 0.0083 0.0333 0.0333 0.005 0.0333 0.0333 0.0008
CM
GE 1
GN 1,0
EX 0,0,1,0,1,0,0,0

For comparison, here is the NEC-4D input for Altshuler's Transactions
antenna (sorry about the line-wrapping):

GW 0, 5, 0.00000, 0.00000, 0.00000, 0.02638, 0.00133, 0.02759, 0.00080
GW 1, 5, 0.02638, 0.00133, 0.02759, 0.00019, 0.03099, 0.02694, 0.00080
GW 2, 5, 0.00019, 0.03099, 0.02694, 0.03001, 0.03022, 0.00907, 0.00080
GW 3, 5, 0.03001, 0.03022, 0.00907, 0.03095, 0.00104, 0.03309, 0.00080
GW 4, 4, 0.03095, 0.00104, 0.03309, 0.00013, 0.00031, 0.03288, 0.00080
GW 5, 4, 0.00013, 0.00031, 0.03288, 0.00048, 0.03129, 0.03330, 0.00080
GW 6, 4, 0.00048, 0.03129, 0.03330, 0.03076, 0.02938, 0.03258, 0.00080
GE 1
GN 1,0
EX 0,0,1,0,1,0,0,0

-Chuck, W1HIS

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