=  NOW 35 WPM  =  TEXT IS FROM NOVEMBER 2021 QST  PAGE 37 =

THE QCX MINI IS A SANDWICH OF TWO PRINTED CIRCUIT BOARDS.  THE MAIN BOARD,
SHOWN IN FIGURE 1, COMES WITH MANY SMD SURFACE MOUNTED DEVICE COMPONENTS
ALREADY INSTALLED.  THE BUILDER ONLY HAS TO ADD STANDARD THROUGH HOLE
PARTS.  THE PARTS YOU MUST INSERT YOURSELF HAVE ALMOST ONE PAGE DEVOTED TO
EACH COMPONENT.  OCCASIONALLY, THE INSTRUCTIONS FOR INSERTING A COMPONENT
RUN OVER TO A SECOND PAGE, SO ITS A GOOD IDEA TO CHECK THE NEXT PAGE FOR
ADDITIONAL INFORMATION.  THE BOARD IS TIGHTLY PACKED, SO TAKE YOUR TIME
BUILDING IT.  LARGE, CLEAR, COLOR PHOTOS AND DRAWINGS MAKE THE CONSTRUCTION
TASK EASIER.  THE TEXT NOTES THAT ADDITIONAL HEAT FROM YOUR SOLDERING IRON
MAY BE NEEDED OCCASIONALLY BECAUSE CONNECTIONS ARE MADE TO THE HIDDEN
GROUND PLANE.  WHEN IT APPEARED MORE HEAT WAS NEEDED, I LEFT THE SOLDERING
IRON ON THE JOINT A BIT LONGER.  FIVE TOROIDS HAVE TO BE WOUND.  T1, THE
INPUT TRANSFORMER, IS CRITICAL AND A BIT CHALLENGING THE MANUAL CALLS IT
THE ONLY REALLY TRICKY PIECE OF ASSEMBLY.  THE INPUT SIGNAL IS ROUTED TO
FIVE TURNS ON T1, WOUND ON A T50 2 TOROID ABOUT THE SIZE OF A DIME.  A
MULTI TURN WINDING ON THE SAME CORE IS RESONANT WITH A VARIABLE CAPACITOR
FOR THE BAND SELECTED.  TWO OTHER FIVE TURN WINDINGS HAVE TO BE PHASED
CORRECTLY AND AS IDENTICAL AS POSSIBLE.  DURING ALIGNMENT, THREE VARIABLE
RESISTORS COMPENSATE FOR SLIGHT DIFFERENCES BETWEEN THESE WINDINGS.  THE
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