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Re: [wsjtgroup] 6 METERS ANTENNA CUBIC CUAD

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  • JAYB
    AT 50 MHZ AND BELOW, QUADS HAVE NO PARTICULAR ELECTRICAL ADVANTAGE OR DISADVANTAGES OVER YAGIS OF EQUAL BOOM LENGTH, ASSUMING BOTH ARE OPTIMALLY FILLED WITH
    Message 1 of 4 , Apr 10, 2002
      AT 50 MHZ AND BELOW, QUADS HAVE NO PARTICULAR ELECTRICAL ADVANTAGE OR DISADVANTAGES OVER YAGIS OF EQUAL BOOM LENGTH, ASSUMING BOTH ARE OPTIMALLY FILLED WITH ELEMENTS AND PROPERLY MATCHED. ABOVE 100 MHZ, QUADS ARE HARDER TO BUILD AND TUNE DUE TO SMALL DIMENSION-TOLERANCE ERRORS. CONTRARY TO INTUITION, THE 
      CENTER-FED QUAD IS HORIZONTALLY POLARIZED AND OFFERS NO POLARIZATION-DIVERSITY ADVANTAGE.
      YAGIS ARE EASIER TO BUILD, ROTATE AND KEEP IN THE AIR IN BAD WEATHER THAN QUADS SO THEIR ADVANTAGE IS PRETTY MUCH MECHANICAL.
      SINCE MOST DX ON 6 METERS IS E OR F-LAYER SKIP, POLARIZATION SHIFT IS A FACTOR DURING MOST OPENINGS. THE OPTIMUM 6 METER DX ANTENNA IS PROBABLY A SET OF CROSSED YAGIS (EG, 6 EL HORIZONTAL AND 6 EL VERTICAL), SEPARATELY FED AND SWITCHABLE FROM THE SHACK. SELECT THE POLARIZATION WITH THE STRONGEST SIGNAL AND KEEP SAMPLING IT DURING THE OPENING. AN ADDITIONAL ADDED FEATURE COULD BE THE ABILITY TO SIMULTANEOUSLY FEED BOTH THE HORIZONTAL AND VERTICAL ANTENNAS THRU VARYING LENGTHS OF PHASING LINES, ALLOWING VARIABLE POLARIZATION ANGLES OF 0, 30, 45, 60, 75 AND 90 DEGREES. THERE ARE TIMES DURING ANY OPENING THAT THE SIGNAL WILL OPTIMIZE AT SOME PARTICULAR POLARIZATION ANGLE BETWEEN 0 AND 90 DEGREES, SO CONTINUALLY SAMPLING THIS ANGLE WITH A COAX SWITCHING ARRANGEMENT SHOULD OPTIMIZE THE POSSIBILITY OF A DX CONTACT.
      TRUTH IS, WAS & DXCC ARE EQUALLY POSSIBLE WITH BOTH STYLES OF ANTENNAS - HAS A WHOLE LOT MORE TO DO WITH PROPAGATION AND LUCK THAN ANYTHING ELSE !!! TOOK ME 42 YEARS TO MAKE DXCC - USED YAGIS, GROUND PLANES, VERTICAL WHIPS, DIPOLES AND LONG WIRES  --- ANYTHING IT TAKES !!!!
      BEST DX TO ALL - LOOKING FOWARD TO THE SUMMER E-S TO BOTH EUROPE AND THE CARRIBEAN.
                       JAY - K2OVS :))
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