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IMPROVED DESIGN.  EQUIVALENT TAYLOR VC2F 13R2 VACUUM RELAYS ARE ALSO
AVAILABLE FROM RF PARTS.  I ADDED A 7R5 KV DC GDT BETWEEN THE ANTENNA
OUTPUT AND GROUND SEE FIGURE 1.  PHILS UPDATED ONLINE ARTICLE INCLUDES A
VARIANT THAT USES A BIAS T TO DELIVER THE CONTROL VOLTAGE.  I ADOPTED THIS
VARIANT.  A SECOND 1 KV GDT IN PARALLEL WITH A 25 M BLEED RESISTOR PROVIDES
STATIC PROTECTION.  EXTERNAL DC BLOCKING STATIC PROTECTORS CANNOT BE USED
WITH THIS DESIGN BECAUSE THEY BLOCK THE CONTROL VOLTAGE TO THE UNIT.  I
USED ANOTHER G2 VACUUM RELAY FOR K2.  UNLIKE PHILS DESIGN, THE LOADING COIL
REMAINS IN CIRCUIT ON 60 METERS AND UP.  THIS ARRANGEMENT COSTS 0R6 AND 0R5
POWER LOSS AT 30 AND 40 METERS, RESPECTIVELY.  ASSEMBLING THE MATCH BOX  I
CHOSE A BUD INDUSTRIES NBF 32316 NEMA BOX FOR THE ENCLOSURE, ADDED A BUD
INDUSTRIES NBX 32916 PL INTERNAL GRID PANEL, AND MOUNTED THE COIL AND RELAY
MINI BOX ON IT.  THE NEMA BOX IS DESIGNED TO ACCEPT THE GRID PANEL WITHOUT
THE NEED TO PENETRATE IT WITH SCREWS.  FIRST, MOUNT THE COIL TO THE GRID
PANEL, AS SEEN IN THE LEAD IMAGE AND IN THE QST IN DEPTH IMAGES.  ZIP TIE
TWO PAIRS OF POLYETHYLENE STANDOFFS SIDEWAYS ON THE LEFT SIDE OF THE GRID
‰  END OF 30 WPM TEXT  ‰  QST DE W1AW  ƒ