A NanoVNA calculates the SWR for you. If this SWR is so important for an OM at the output of its Tx, it is not a very relevant measurement produced by a NanoVNA.
SWR is a number and only *one*
A NanoVNA is a measuring device that allows you to measure a couple of *two* numbers as a function of frequency using only port 0. The NanaoVNA will present these two numbers to you in multiple forms adapted to a particular use. The two most important:
- The impedance in the form A+jB (A et B in ?)
- Parameter S11 in the form again a+jb
For example, if you notice that at the output of your Tx you have a high SWR, not very compatible with a Tx with transistors, what is relevant is to correct your installation to reduce this SWR. This SWR is the consequence of the fact that the impedance brought back by your antenna + the transmission line is not 50 + j0 or 50. You must correct your installation and the NanoVNA will help you calculate the device to be implemented.
A simple doublet resonating at the frequency of use never presents an impedance of 50. Do not stop at the evaluation of the SWR by your NanoVNA. The SWR is only a sterile observation.
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F1AMM
Fran?ois
