[Elecraft] Elecraft CW Net Announcement

[kevin]

Good Evening,

    It was a mild, smokey week.  Wind moves the smoke around though you 
can still taste it.  The wind also causes a steady rain of fir needles.  
Dry weather has caused more of them to die off. Black berries are not 
doing very well.  The jays have a lean and hungry look.

    The sun has few sunspots today but it is still fairly active. They 
are losing track of individual CMEs.  Each has its own velocity so they 
can merge or pass one another.  The auroral oval shows when they are 
energize the ionosphere.



Please join us on (or near):

14050 kHz at 2200z Sunday (3 PM PDT Sunday)
  7047 kHz at 0000z Monday (5 PM PDT Sunday)


73,
       Kevin.  KD5ONS



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To model the Real part of the 1/4 wave vertical antenna radiation pattern

#define ETA  376.99111842000     // eta = 120 * PI;  // in free space

double f = 100;      // frequency in MHz
double h = 1;           // height of antenna
double I0 = 2;       // maximum current in amperes
double r = 100;      // distance from antenna to observer
double size = 50;    // used for scaling

lambda = 300 / f;    // wavelength in meters
l = lambda / 4;      // length of antenna  1/4 wave
k = 2*PI / lambda;  // to save some space

Sweep radius around the Y axis
for {0 <= phi <= 2*PI}
stepping along from {0 <= theta <= 2/PI}

radius = size * cos(k * r) * (k * l * ETA * cos(theta) * cos(h * k * 
sin(theta)) * I0) / (2*PI * r);

For the imaginary part sweep

radius = size * sin(k * r) * (k * l * ETA * cos(theta) * cos(h * k * 
sin(theta)) * I0) / (2*PI * r);