Collinear Array of 4 Dipoles
Free Space
144 MHz
4 wires, inches
6  0 0   0  0 0  39  .5
6  0 0  78  0 0 117  .5
6  0 0 156  0 0 195  .5
6  0 0 234  0 0 273  .5
4 sources
3,100,0
8,100,0
13,100,0
18,100,0
0 loads

Note from the elevation plot that even a small error in vertical alignment will
reduce the gain at the horizon.  Also note how the end elements have a slightly
different input Z than the inner dipoles.