The modification is suggested by Hugen "
Since LiteVNA is designed to work without a battery installed, it switches to using USB power directly when connected to USB power. When working with the USB power supply, the voltage of the input DC-DC boost power supply is very close to the voltage of the output, resulting in a very narrow PWM pulse bandwidth of the switching power supply, and these pulses may enter the IF, resulting in large measurement noise.
To avoid this interference, the power supply circuit can be modified so that the input to the switching power supply always comes from LiteVNA64 circuits are slightly different, with the following modifications.
LiteVNA64: Remove D1 R7 R1
Please disconnect the battery and USB power connection when modifying the circuit. The battery must be connected after the modification is completed to work properly.
"For me is impossible to make this modification for my sight and some shaking hand"