‰  NOW 40 WPM  ‰  
MINI BOX.  FINALLY, SOLDER THE 100 UH CHOKE TO THE FEED THROUGH USING AS
SHORT A LEAD AS POSSIBLE.  SOLDER A PIECE OF 18 AWG SOLID HOOKUP WIRE TO
THE LONG LEAD OF THE CHOKE.  SHRINK WRAP THIS JOINT AND TIE THE HOOKUP WIRE
TO THE GRID, LEADING DOWN TO THE SO 239 CONNECTOR.  I SEPARATED THE GROUND
WIRES FOR THE MINI BOX AND THE 7R5 KV GDT TO REDUCE COUPLING, AND RAN THEM
DIRECTLY TO THE GROUND POST UNDER THE COIL.  TO CONNECT THE ANTENNA, I USED
A SHORT LENGTH OF 14 AWG MARINE GRADE HI

AN IMPROVED 160/80 METER MATCHING NETWORK FOR YOUR 43 FOOT VERTICAL  PUT
YOUR 43 FOOT VERTICAL ANTENNA TO WORK ON TWO POPULAR LOW BANDS.  STEVE
MASTICOLA, WX2S  I DECIDED TO ADD A ZEROFIVE ANTENNAS TILT OVER 43 FOOT
MAST TO ADD 160 METER CAPABILITY TO MY STATION.  THE SYSTEM MUST BE MATCHED
AT THE ANTENNA, OR MOST OF THE POWER OUTPUT IS LOST IN THE TRANSMISSION
LINE.  I BASED MY MATCH DESIGN ON A PHIL SALAS, AD5X, ARTICLE.  THAT DESIGN
SOON FAILED.  SUBSEQUENTLY, PHIL ADVISED ME THAT MY ANTENNA GROUNDING
SYSTEM MIGHT HAVE BEEN TOO GOOD FOR HIS ORIGINAL DESIGN.  HE HAD ASSUMED AT
LEAST 10 OF GROUND LOSS, WHICH MADE THE ARRAY SOLUTIONS RELAYS HE SPECIFIED
MARGINALLY ADEQUATE, AT 1,500 W ON 160 METERS.  THIS IS HOW I BEEFED UP
PHILS DESIGN SEE THE LEAD PHOTO.  AN UPGRADED MATCH  I SUBSTITUTED THREE 15
KV VACUUM RELAYS FOR THE TWO RF 3PDT 15 PARTS, AND ENCLOSED ALL THE RELAY
CONTROL ELECTRONICS IN A GROUNDED MINI BOX TO MINIMIZE THE POSSIBILITY OF
RF GETTING INTO THE RELAY CONTROLS.  I KEPT THE LEAD LENGTHS TO THE
ABSOLUTE MINIMUM FOR THE DC CONTROL VOLTAGES OUTSIDE THE MINI BOX, AND
BYPASSED THOSE LEADS AS THEY ENTERED THE MINI BOX.  I INSTALLED A 7R5 KV
GAS DISCHARGE TUBE GDT FOR RELAY OVER VOLTAGE PROTECTION, AND ADDED A
SECOND 1 KV GDT AND BLEED RESISTOR TO THE RF INPUT FOR BUILT IN STATIC
DISCHARGE PROTECTION.  I USED THREE GIGAVAC G2 SPDT VACUUM RELAYS IN THE

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 40 WPM TEXT  ‰  QST DE W1AW  ƒ