There have been recent discussions about the interchangeability of coaxial plugs and sockets, their dimensions and their impedances. But, as usual, the magnitude of the electrical effects is never mentioned. Without numbers nobody knows what they are talking about.

A coaxial connector is a very short length of transmission line but at UHF and microwave frequencies it is an appreciable fraction of a wavelength. When 1/4-wavelength long it has the property of transforming a mismatched termination to another value. When

1/2-wavelength long the input impedance repeats the value of the termination. The SWR on an adjacent line is a function of the input impedance.What is the effect of using a 75-ohm coaxial connector in a 50-ohm system?

What is the effect of using a length of transmission line of 50-ohms nominal impedance when it is actually 53 ohms?

With mixed values of line Zo at what high frequency does the SWR and reflection loss become excessive?

Program CONNECT.exe calculates the effect of inserting a length of line in a system of different Zo. Differences can be large or small. Line length can be physically very short.

For a given frequency, mismatched Zo's and a velocity factor, input impedance, SWR, reflection coefficient and reflection loss are calculated. (Reflection loss is sometime known as mismatch loss).

The program is worded in terms of a connector mismatch but has other applications.

Input data can be varied in small increments from the keyboard while observing the effects on calculated values. Download CONNECT from website below. It has entertainment, educationaal and practical value. Amuse yourselves!

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