3-15
Q20. All the power sent down a transmission line from a transmitter can be transferred to an antenna
under what optimum conditions?
Q21. What symbol is used to designate the characteristic impedance of a line, and what two variables
does it compare?
Characteristic Impedance and the Infinite Line
Several short sections, as shown in figure 3-15, can be combined to form a large transmission line, as
shown in figure 3-16. Current will flow if voltage is applied across points K and L. In fact, any circuit,
such as that represented in figure 3-16, view A, has a certain current flow for each value of applied
voltage. The ratio of the voltage to the current is the impedance (Z).
Recall that:
Figure 3-16.—Characteristic impedance.
