Re: nanoVNA Output Voltage


Warren Allgyer
 

Some clarification from my earlier measurement.

The Measurement output from CH0 ranges from -13 dBm at 55 kHz to -36 dBm at 900 MHz..... a more than 23 dB variance.

Beginning at the first increment above 300 MHz the Measurement output switches from fundamental to 3rd harmonic. So, for example, when measuring at 330 MHz the 330 MHz Measurement output being used will be at -19 dBm the there will also be a much higher power fundamental signal output at 110 MHz at -9 dBm. The Nanovna ignores this fundamental frequency by virtue of its heterodyne mixing but users should be aware of its presence when performing S21 measurements of preamps and the like. These relatively high power fundamental frequencies can easily overload amplifiers and distort measurement results.

Another example: The Measurement output at 900 MHz is way down at -36 dBm but the 300 MHz fundamental that is generating that measurement frequency is also present at a whopping -9 dBm, nearly 30 dB higher! User beware!

Warren Allgyer

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