Slide 16 of 19

Notes:

With two towers spaced between one-half and five-eighths of a wavelength apart (spacing not critical), a broadside array of two identical Spitfires can be constructed, as shown in the figure. Both Spitfires are fed in phase from a coax T. The maximum gain is broadside to the array and it can be switched in the forward and rear directions. This array provides almost 3 dB additional gain over a single Spitfire. Note that end-fire operation is also possible, using the in-plane parasitic wings (not shown in the figure above) of a 4-wing Spitfire and using 180 degree phasing, with a half-wave coaxial delay line. The end-fire array provides about 1 dB less gain than the broadside version. Selectable broadside and end-fire modes of operation allows a 2-tower system to cover 4 quadrants.