#G9B01🔗
What is a characteristic of a random-wire HF antenna connected directly to the transmitter?
直接连接到发射机的随机线高频天线有什么特点？
#G9B02🔗
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?
以下哪种是将升高的四分之一波接地平面垂直天线的馈电点阻抗调整为大约 50 欧姆的常用方法？
#G9B03🔗
Which of the following best describes the radiation pattern of a quarter-wave ground-plane vertical antenna?
以下哪项最能描述四分之一波长接地平面垂直天线的辐射方向图？
#G9B04🔗
What is the radiation pattern of a dipole antenna in free space in a plane containing the conductor?
在包含导体的平面的自由空间中，偶极子天线的辐射方向图是什么？
#G9B05🔗
How does antenna height affect the azimuthal radiation pattern of a horizontal dipole HF antenna at elevation angles higher than about 45 degrees?
天线高度如何影响水平偶极高频天线在仰角高于 45 度左右时的方位角辐射方向图？
#G9B06🔗
Where should the radial wires of a ground-mounted vertical antenna system be placed?
地面垂直天线系统的径向线应放置在哪里？
#G9B07🔗
How does the feed point impedance of a horizontal 1/2 wave dipole antenna change as the antenna height is reduced to 1/10 wavelength above ground?
当天线高度减小到距地面 1/10 波长时，水平 1/2 波偶极天线的馈电点阻抗如何变化？
#G9B08🔗
How does the feed point impedance of a 1/2 wave dipole change as the feed point is moved from the center toward the ends?
当馈电点从中心向两端移动时，1/2 波偶极子的馈电点阻抗如何变化？
#G9B09🔗
Which of the following is an advantage of using a horizontally polarized as compared to a vertically polarized HF antenna?
与垂直极化高频天线相比，使用水平极化高频天线有以下哪些优点？
#G9B10🔗
What is the approximate length for a 1/2 wave dipole antenna cut for 14.250 MHz?
14.250 MHz 的 1/2 波偶极天线切割长度大约是多少？
#G9B11🔗
What is the approximate length for a 1/2 wave dipole antenna cut for 3.550 MHz?
3.550 MHz 的 1/2 波偶极天线切割长度大约是多少？
#G9B12🔗
What is the approximate length for a 1/4 wave monopole antenna cut for 28.5 MHz?
28.5 MHz 的 1/4 波单极天线切割长度大约是多少？
