‰  NOW 35 WPM  ‰  TEXT IS FROM SEPTEMBER 2017 QST  PAGE 39‰

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
‰  END OF 35 WPM TEXT  ‰  QST DE W1AW  ƒ