function s = lazyh(frq,pos,dir)
% lazyh(frqpos,dir)
% LazyH-antenna
% frq :  Frequency in MHz
% pos :  [x y z]-vector of center of mass position of the antenna
% dir :  main radiation direction: Euler's angles or transformation matrix.
%        See function rotation for details.

% Author:  Klaus von der Heide, e-mail:  dj5hg@qsl.net

% Default
% =======
if nargin<1  frq = 28.1; end

% Constants
% =========
c = 299792458;               % speed of light
l2 = c/10^6*frq/2;           % half wavelength
l4 = l2/2;                   % quarter of wavelength
r = l2/10;                   % half spacing of feeder
d = 0.002*ones(1,9);         % diameter of wires
a = [0 -r 0; 0 -r  0; 0 +r  0;  0 -r 0;  0 +r 0; 0 +r l2; 0 -r l2; 0 +r l2; 0 -r  l2]; % one end of wires
b = [0 +r 0; 0 -l2 0; 0 +l2 0; -r 0 l4; +r 0 l4; -r 0 l4; +r 0 l4; 0 l2 l2; 0 -l2 l2]; % second end of wires
m = [3 7 7 16 16 16 16 7 7]; % number of segments per element
e = [1 0 0 0 0 0 0 0 0];     % only one excitation point
p = 0;                       % phase 0 for feed point

% Construction
% ============
s = wires(a,b,d,m,e,p);

% Possible shift and rotation
% ===========================
if nargin>1  s = translation(s,pos); end
if nargin>2  s = rotation(s,dir);    end
