‰  NOW 40 WPM  ‰  TEXT IS FROM MARCH 2014 QST  PAGE 31‰
TO 3R5 MHZ AND CONNECTED IT TO THE BOTTOM OF THE ANTENNA THROUGH A HAND
WOUND COIL THAT HAD AN INDUCTANCE OF ROUGHLY 10.  USING A CLIP LEAD, I
VARIED THE CONNECTION POINT ON THE THE COIL UNTIL I FOUND THE MINIMUM SWR
POINT.  I THEN MEASURED THE INDUCTANCE OF THE PORTION OF THE COIL FEEDING
THE ANTENNA AND LET THIS BE L0.  TO DETERMINE C0, I USED A SIMILAR
PROCEDURE, FIRST SETTING THE ANTENNA ANALYZER TO 3R8 MHZ AND THEN
CONNECTING IT TO THE BASE OF THE ANTENNA

PAST, BUT THEY MUST BE PARTIALLY STRETCHED TO HOLD THE ANTENNA REASONABLY
FLAT AND WITH THE FIRST GOOD STORM, THEY OFTEN END UP SPRUNG AND HOLDING UP
A DROOPY ANTENNA.  I FINALLY CAME UP WITH THE SCHEME SHOWN IN FIGURE 6,
WHICH ADDS A WEAK LINK THAT WILL BREAK BEFORE THE ANTENNA STRETCHES.  THE
EXTRA LOOP KEEPS THE ANTENNA FROM FALLING TO THE GROUND.  TRAP THE TRAP
COIL IS MADE FROM 39 TURNS ON A 1R66 INCH DIAMETER FORM OF 13 AWG INSULATED
COPPER WIRE USED FOR ELECTRICAL APPLIANCE POWER CORDS SEE FIGURES 7 AND 8.
THE CAPACITOR IS MADE FROM RG 58C/U COAX CABLE, WHICH HAS A CAPACITANCE OF
28R5 TO 30 PF/FOOT.  ABOUT 4 FEET OF THE RG 58 FORMS A 113 PF CAPACITOR
THAT IS RELIABLE TO 5 KV, SO USING UP TO 500 W OF RF SHOULD NOT BE A
PROBLEM, OTHERWISE, IF YOU PLAN TO TRANSMIT WITH MORE POWER, YOU SHOULD USE
A DOORKNOB CAPACITOR.  TUNING THE TRAP TO 3R600 MHZ IN THE SHACK WILL YIELD
A 3R650 MHZ RESONANT POINT IN THE AIR.  IF YOU USE A GRID DIP METER YOU CAN
TUNE THE TRAP BY CUTTING THE COAX TO THE RIGHT LENGTH.  TAKE CARE TO KEEP
THE COAX SHIELD SAFELY APART FROM THE INNER LEAD TO AVOID ARCING.  SECURE
THE 4 FOOT COAX CAPACITOR TO THE SIDE OF THE ANTENNA WHERE THE SHIELD OF

TUNING FIRST, SET THE RESONANCE OF THE TRAP TO 3R620 MHZ IN THE SHACK.
AFTER HAVING ERECTED THE ANTENNA, TUNE THE WHOLE SYSTEM TO RESONATE IN THE
CENTER OF THE DESIRED PORTION OF THE 75 METER BAND.  THIS ANTENNA WILL
COVER ABOUT 200 KHZ WITH AN SWR OF 1 2 AND 300 KHZ WITH AN SWR OF 1 3 SEE
FIGURE 4.  NEXT, ADJUST THE LONG PART OF THE ANTENNA BEYOND THE TRAP FOR
THE PORTION OF TOP BAND THAT YOU WANT TO USE.  MEASUREMENTS ON THIS ANTENNA
SHOULD BE MADE AT THE BASE OF THE VERTICAL ELEMENT.  IF THAT IS NOT
CONVENIENT, THEN USE AN EXTENSION COAX CABLE ONE HALF WAVELENGTH LONG.
HOWEVER, BE SURE TO REDUCE THE CABLE LENGTH BY ITS VELOCITY FACTOR FRACTION
VF.  CONSTRUCTION THE ANTENNA SYSTEM HAS THREE EQUALLY IMPORTANT PARTS THE
ANTENNA ITSELF COMPRISED OF THE WIRE, INSULATORS, A MEANS OF TUNING AND
SUPPORT, THE TRAP, AND THE GROUND SYSTEM.  ANTENNA FOR MY LOW BAND ANTENNA
I USED 15 AWG STRANDED STEEL WIRE.  TUNING IS EASIER IF THE WIRE HAS NO
INSULATION AT THE ENDS.  AT EACH END, I FOLDED IT BACK TO FORM A LOOP THAT
I SECURED WITH A WIRE ROPE CLIP, AS SHOWN IN FIGURE 5.  THE ANTENNA IS
TUNED BY LENGTHENING OR SHORTENING THE LOOP, WHICH SHIFTS ITS RESONANT
FREQUENCY.  AN ANTENNA FASTENED TO A TREE IS SUBJECT TO EXTRA STRESS DURING
A STORM AND THE ANTENNA MAY BREAK OR BE STRETCHED IF THERE IS NO MEANS TO
ABSORB THE EXTRA TENSION AS IT MOVES.  I HAVE TRIED USING SPRINGS IN THE
‰  END OF 40 WPM TEXT  ‰  QST DE W1AW  ƒ