Calibration of the power indicator/SWR using NanoVNA?

[Karavan]

Good time to all!
Can I calibrate the "8.6 R shunt" parameter as follows:
1. Measure the SWR of the antenna with the NanoVNA device;
2. Select the value "8.6 R shunt" at which the readings of my (tr)uSDX will coincide with the readings of NanoVNA.
Will this calibration be correct?
Best regards, UB8CQB, 73!

[dl6sez]

No!
R shunt is the pcb resistor for efficiency calculations!

73 de Chris

[vk2tty]

Will this calibration be correct?

Yeah, nah, as DL6SEZ said R Shunt is used to calculate power and efficiency. Nothing your NanoVNA can tell you will help you calibrate it. Instead, you need to measure:

• how much power your radio uses for transmitting
• how much power gets out your RF port

… and then change R Shunt until what the radio displays matches reality.

Power input is easy to measure with a lab power supply, but you could also measure voltage and current with a multimeter. For power output, you'll need a power meter or an oscilloscope's RMS measure.

See DLMAN's post in this other thread for more details on what to do with the measurements:

RShunt is the resitance of the shunt PCB-trace, for Drain Current measurement on RF Board around U1 (INA219). It turned out, PCB Trace resistance is not as constant as we thougt it would be.

It is not intended to "fake" Efficiency, when there is none, but to have a possibility to "calibrate" your internal measurement, so it matches external measurements.

try to measure as exactly as possible…