‰  NOW 30 WPM  ‰  TEXT IS FROM SEPTEMBER 2013 QST  PAGE 39‰

SET OF DRIVE CURRENTS, PROVIDES A BASIS FOR COMPARISON SEE FIGURE 12.  IT
SHOWS THAT THE FORWARD GAIN SHOULD BE 7R32 DB, THE HIGHEST ATTAINABLE VALUE
ON THIS PRACTICAL GROUND.  THE BEHAVIOR IN THE REAR SECTION IS DETERMINED
BY THE DEGREE OF CANCELATION OF THE FIELDS FROM THE FOUR ELEMENTS.  IT IS
HERE THAT SMALL DIFFERENCES BETWEEN THE FIELD COMPONENTS BECOME APPARENT
AND REFLECT IMPERFECTIONS IN THE ARRAY AND ITS FEED SYSTEM THAT CAUSE
ERRORS IN THE DRIVE CURRENTS.  FIGURE 13 REPRESENTS THE SUPERIMPOSED DATA
ON RECTILINEAR AXES TO AID COMPARISON.  THERE IS SIGNIFICANT AND CONSISTENT
DETAIL IN THE REAR SECTOR.  THE OVERALL IMPRESSION IS OF SIMILARITY IN THE
MAIN LOBES FOR THE FOUR BEAM HEADINGS.  THE ACTUAL DRIVE CURRENTS WERE
INSERTED INTO THE SIMULATION AND THE PREDICTED GAIN VALUES COME CLOSE TO
THE MAXIMUM ATTAINABLE ON THE HYBRID GROUND, COMPARE FIGURES 12 AND 14.
THE OBSERVED FRONT TO BACK RATIOS WERE AT LEAST 20 DB ON THIS GROUND AND
FIGURE 12 SUGGESTS THAT AN IMPROVEMENT BY 3 TO 4 DB MIGHT BE ACHIEVABLE.
ALTHOUGH APPRECIABLE, IT IS QUESTIONABLE IF THIS IMPROVEMENT WOULD HAVE
PRACTICAL VALUE SINCE THE RATIO WAS ALREADY 20 DB.  IT IS INTERESTING TO
‰  END OF 30 WPM TEXT  ‰  QST DE W1AW  ƒ