‰  NOW 35 WPM  ‰  TEXT IS FROM JULY 2014 QST  PAGE 55‰

THE DOCTOR IS IN JOEL R. HALLAS, W1ZR, W1ZR ARRL. ORG  HOW DO YOU ADJUST A
NON RESONANT ANTENNA?   Q I JUST PUT UP AN EXTENDED DOUBLE ZEPP EDZ ANTENNA
FOR 30 METERS.  TO GET THE SWR DOWN, DO I ADJUST THE LENGTH OF THE ANTENNA,
OR DO I ADJUST THE LENGTH OF THE 450 MATCHING SECTION?  THE ONLY AVAILABLE
MEASUREMENT EQUIPMENT I HAVE IS AN SWR BRIDGE.  SHOULD I USE MY 4 1 BALUN
BETWEEN THE MATCHING SECTION AND THE COAX?  A THE EDZ SEE FIGURE 1 IS A
GREAT ANTENNA.  IT PROVIDES AS MUCH BROADSIDE GAIN AS YOU CAN GET FROM A
SINGLE ELEMENT, RESULTING IN THE SHARP PATTERN SHOWN IN BLACK IN FIGURE 2.
THIS IS GREAT IF YOU WANT TO FOCUS TOWARD THE TWO BROADSIDE DIRECTIONS.
NOTE THAT THE GAIN ACHIEVED COMPARED TO A 1/2 WAVE DIPOLE BLUE PATTERN IN
FIGURE 2 AT THE SAME HEIGHT IS ABOUT 3R1 DB, RESULTING FROM THE NARROWING
OF THE BEAMWIDTH FROM 86 TO 36 ON EACH SIDE.  AN IN BETWEEN ANTENNA IS THE
NON EXTENDED DOUBLE ZEPP, ALSO KNOWN A TWO 1/2 WAVES IN PHASE, OR FULL WAVE
DIPOLE, IS SHOWN IN RED.  THE TRICKY THING ABOUT ADJUSTING THE EDZ IS THAT,
UNLIKE THE OTHER TWO, IT ISNT NECESSARILY RESONANT IN ANY BAND, ALTHOUGH
YOUR 122R6 FOOT LENGTH SHOULD BE CLOSE TO 1/2 WAVE RESONANCE AT 3R63 MHZ
AND IT SHOULD SHOW A LOW SWR THERE, IF TEMPORARILY FED WITH 50 COAX INSTEAD
OF WINDOW LINE.  THE EXACT ANTENNA RESONANCE, AS WELL AS THE IMPEDANCE AT
10R125 MHZ WILL BE DIFFERENT FROM THE DESIGN POINT IF THE HEIGHT, WIRE
‰  END OF 35 WPM TEXT  ‰  QST DE W1AW  ƒ