‰  NOW 20 WPM  ‰  TEXT IS FROM SEPTEMBER 2019 QST PAGE 32 ƒ

CURRENT BALUN WOUND WITH 18 GAUGE SPEAKER WIRE ON 61 MATERIAL TOROID CORES
AS BEEN SHOWN TO DELIVER THE REQUIRED 4 1 IMPEDANCE TRANSFORMATION WITH
LESS THAN 0R2 DB LOSS UP TO 30 MHZ.  THE S OCFD BALUN USES 10 TURNS OF
SPEAKER WIRE ON EACH OF TWO FT140 43 TOROID CORES TO INCREASE THE CHOKING
REACTANCE TO ABOUT 2,000, IN KEEPING WITH THE RULE OF THUMB THAT THE
CHOKING REACTANCE SHOULD BE 10 TIMES THE FEED POINT IMPEDANCE.  THIS MAY
INCREASE LOSSES AT THE HIGH END OF THE FREQUENCY RANGE, THOUGH NO
MEASUREMENTS WERE PERFORMED.  SIX TURNS OF THE RG8X FEED LINE WERE WOUND
THROUGH A THIRD FT140 43 CORE AT THE BALUN INPUT TO FURTHER CHOKE OFF
IMBALANCED CURRENTS THAT MIGHT OTHERWISE FLOW ON THE OUTSIDE OF THE COAX
SHIELD.  THE SPEAKER WIRE TRANSMISSION LINES WERE WOUND AND CONNECTED AS
‰  END OF 20 WPM TEXT  ‰  QST DE W1AW  ƒ