‰  NOW 30 WPM  ‰  TEXT IS FROM JUNE 2017 QST  PAGE 47 ‰

INCLUDE A FAN DIPOLE, A CENTER FED ZEPP AND A TUNER, OR A THREE BAND TRAP
DIPOLE.  ALL COULD WORK, BUT THE ZEPP REQUIRES A WIDE RANGE TUNER AND
ASSOCIATED OPERATING COMPLICATIONS.  IT ALSO HAS A NARROWER PATTERN ON THE
HIGHER BANDS.  THE TRAP DIPOLE REQUIRES ADDITIONAL COST AND CONSTRUCTION
COMPLEXITY TO MAKE AND TEST THE TRAPS.  THE THREE BAND COUPLED RESONATOR
DIPOLE I MODELED A COUPLED RESONATOR USING PARALLEL WIRES THAT COULD BE
HELD AT THE APPROPRIATE SPACING BY INSULATING SPACERS, AND IT CAME OUT VERY
WELL, AT LEAST ON THE MODEL.  THE FINAL DIMENSIONS OF BOTH THE WIRES AND
SPACERS ARE SHOWN IN FIGURE 1.  THE EZNEC MODELED SWR OF THE ANTENNA ON
EACH BAND, INCLUDING THE EFFECT OF 75 FEET OF RG 8X COAX, IS SHOWN IN
FIGURES 2 4.  THE MODEL ASSUMED A TYPICAL FIELD DAY HEIGHT OF 30 FEET ABOVE
MEDIUM GROUND CONDUCTIVITY 0R005 S/M, RELATIVE DIELECTRIC CONSTANT OF 13.
THE TUNING DOESNT CHANGE MUCH GOING 10 FEET EITHER WAY.  DESIGN TO
PERFORMANCE  FOR A COUPLED RESONATOR TO WORK AS DESIRED, THE FEED MUST BE
CONNECTED TO THE LOWEST FREQUENCY HALF WAVE, FED JUST LIKE A SINGLE BAND
DIPOLE.  THE OTHER TWO HALF WAVES HAVE NO DIRECT CONNECTION THEY ARE
‰  END OF 30 WPM TEXT  ‰  QST DE W1AW  ƒ