It computes the lengths of two different types (impedances) of transmission line
Edit by : SMC computes the lengths of two different types (impedances) of Transmission lines. When these two lines are connected in series (in the right order!), they perform an impedance match Between a 50 Ohm transmission line, and a complex impedance, usually the impedance at an antenna. The goal is to reduce the SWR to 1.0.

In the typical scenario, the antenna impedance is close to, but not exactly, 50 Ohms of resistance (50 + j 0 Ohms). The SWR will, therefore, be greater than 1.0. It is desired to lower the SWR as much as possible. Available resources include 50 Ohm transmission line, and transmission line of another impedance. Often this is 75 Ohm line, such as RG-11. It could be a parallel Combination of 50 Ohm line, creating a 25 Ohm line. It can be any line or parallel combination of lines that has an impedance other than 50 Ohms. An antenna analyzer or other measurement device is used to determine the impedance at the antenna. The Frequency, antenna impedance, and the important characteristics (impedance and velocity Factor) of the two lines are supplied to SMC. It then computes two lengths, a length of 50 Ohm line, and a length of the other line. The 50 Ohm line is connected directly to the load, usually the antenna. The other impedance line is connected to the opposite end of the 50 Ohm line. Their combination results in the transformation of the load impedance into 50 Ohms at the input of the second line section. From that point, standard 50 Ohm transmission line runs the remainder of the distance back to the radio, with an SWR of 1.0.

This technique will not work on all load impedances. There is a finite range of impedance values which can be matched by this technique. The range is related to the impedance values of the two transmission lines. The range is increased when the impedance between the two different transmission line impedances increases. you can free download Series Matching Calculator Software 1.01 now.