Which of the following is a common way to adjust the feed point impedance of an elevated quarter-wave ground-plane vertical antenna to be approximately 50 ohms?
Slope the radials upward
Slope the radials downward✓الإجابة الصحيحة
Lengthen the radials beyond one wavelength
Coil the radials
الشرح
A quarter-wave ground plane with horizontal radials has a feed point resistance near 20 to 35 ohms; sloping the radials downward raises it toward 50 ohms so that common coax matches it. Sloping them upward moves the impedance the wrong way.