=  NOW 13 WPM  =  TEXT IS FROM APRIL 2024 QST PAGE 37  =

ELEMENT IS FED WITH A BALANCED TWINLEAD TRANSMISSION LINE WITH AN INVERTED
PHASE FOR EACH ELEMENT.  THIS IS DONE BY TWISTING THE TWINLEAD BETWEEN EACH
ELEMENT, OR SIMPLY CROSSING THE SHORT JUMPER WIRES THAT CONNECT THE TWINLEAD
TO THE ELEMENTS.  THE PARAMETERS OF THE LPDA DETERMINE THE REQUIRED
CHARACTERISTIC IMPEDANCE OF THE FEED LINE.  IN THIS DESIGN, A 200 OHM
DRIVING POINT IMPEDANCE IS ACHIEVED WITH 250 OHM TWINLEAD. BECAUSE THIS IS
NOT A COMMERCIALLY AVAILABLE TWINLEAD IMPEDANCE, I CONSTRUCTED THE LINE
<  QST DE W1AW  =
USING 8 AWG BARE COPPER WIRE SPACED 0R51 INCH CENTER TO CENTER.  REMOVE ANY
KINKS IN THE UNROLLED BARE WIRE BY CLAMPING ONE END IN A VICE AND PULLING
HARD ON THE OTHER END TO SLIGHTLY STRETCH THE WIRE.  USING SHORT PIECES OF
THE RIPPED PVC BOARD, DRILL 0R51 INCH HOLES CENTER TO CENTER TO SERVE AS
SMALL SPACERS ROUGHLY 2 FEET APART ALONG THE FEED LINE.  SCREW THESE SPACERS
TO THE ELEMENT BRACKETS TO STABILIZE THE FEED SPACER SUPPORTED ON STANDOFFS.
=  END OF 13 WPM TEXT  =  QST DE W1AW  <