‰  NOW 30 WPM  ‰  TEXT IS FROM MARCH 2014 QST  PAGE 50‰

EDITION, REPEATED IN THE FEBRUARY 2013 ARTICLE.  IN THAT EXAMPLE, THE
WEIGHT OF THE WIRE W IS GIVEN AS 0R011 POUNDS PER FOOT AND THE SPAN S,
BEING THE TOTAL DISTANCE BETWEEN SUPPORTS, WOULD BE 420 FEET.  NOTE THAT
THE CURRENT EDITION OF THE ARRL ANTENNA BOOK DEFINES A HALF SPAN AS HALF
THE HORIZONTAL DISTANCE BETWEEN SUPPORTS, WHICH WAS 210 FEET.  THIS IS
CONSISTENT WITH THE NOMOGRAPH.  NOTE 2 OF THE NOMOGRAPH INSTRUCTIONS IN THE
FEBRUARY 2013 ARTICLE ALSO DEFINES SPAN AS ONE HALF THE DISTANCE BETWEEN
SUPPORTS.  FOR THE ABOVE EQUATIONS, HOWEVER, SPAN IS DEFINED AS THE TOTAL
HORIZONTAL DISTANCE BETWEEN THE SUPPORTS.  THE WIRE TENSION T USED IN THE
EXAMPLE IS 50 POUNDS.  SUBSTITUTING W, S, AND T INTO EQUATION 1, THE
COMPUTED RESULT FOR SAG IS 4R852 FEET.  USING THE MUCH MORE CONVENIENT
EQUATION 2, THE RESULT IS 4R851 FEET.  THE SIMPLER FORMULA IS CERTAINLY
ADEQUATE.  NOTE THAT THE RESULT GIVEN BY THE NOMOGRAPH, WHICH GOES BACK TO
THE JANUARY 1966 ARTICLE IN QST, IS 4R7 FEET.  THIS IS AFTER SORTING OUT
AMBIGUITIES IN THE DEFINITION OF SPAN.  IT IS CLEARLY A SUFFICIENTLY
ACCURATE RESULT, AND THE SMALL DIFFERENCE REFLECTS THE INEVITABLE
‰  END OF 30 WPM TEXT  ‰  QST DE W1AW  ƒ