For those that do not have a translator here is the text of Valentino's post:
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The Nanovna is a low-cost, very versatile and easy-to-use instrument. It has a mediocre dynamic range and is very useful for displaying the response curve of a filter. However, if used to calibrate filters, it is slow in displaying the curve and this shortcoming prevents its use in filter calibration, it becomes stressful if there are many components to adjust because between one adjustment and another a couple of seconds can pass. It is also not able to perform measurements on mixers.
John Cunliffe W7ZQ