1.Two thirds of the output of an antenna comes out the bottom half of the antenna.
2.The larger the radius the better the Q of the antenna. Quality Factor (Q) of components.
3.The larger the coax the better the Q. RG-58, around ¼ ”, has a higher loss than RG 213/RG-8, around ½ ”.
4.The larger the spread at the feed point (center insulator) of a dipole, the better the Q.
5.All wire has a velocity factor that’s not in free space. A transmission line may have an insulator around the wire which
slows the wave travel down (VF).
6.Feed line, twin-lead (remember currents flow on the outside of each wire) has a lower loss than coaxial cable. With coax
currents flow on the outside of the center wire and the inside
and outside of the outer shield, that can act as three wires.
7.The higher the Q the better the bandwidth. On 20 meters with a 2:1 SWR, the antenna has a bandwidth of 50Khz (low Q) or a bandwidth of 500Khz (higher Q).
8.Antenna tuners do not change the SWR of the antenna.
9.Testing an antenna. For the best SWR test, the meter should be at the antenna, or in the feed line at ½ wave or 1 wave at the antenna frequency.
