Also the PSU situation below HF frequencies can depend upon atmospheric and local noise levels. From the same Kiwi forum thread, here is a graphic of potential interest:
https://forum.kiwisdr.com/uploads/551/TZU5V3FBWOIL.pngOne might never even notice much, if any discernible RFI from an Apple USB-C charger or similar moderately decent switcher if the PSU noise falls well below the radio's received RF noise level. The Apple USB-C likely suffices for many, especially at MW and above frequencies.
PSU noise on lower frequencies can become an serious issue with many power supplies. The Apple USB-C as measured gets rather noisy below 300KHz, and I suspect that was measured with a rather clean AC source given the person testing it. Expect likely (much) worse RFI with less filtered switching models; plus admittedly a regulated linear supply is a no guarantee down there as well. It can be a huge YMMV situation.
Previously I had my Kiwi on a Samsung USB-C charger, and IIRC, even an Anker USB-C charger for awhile during initial testing. They worked for the purpose, though IIRC, lower MW and further down did have some noise annoyances.
Many of the linear regulated power supplies used in the PLC industry tend to be decent to excellent performance and can be found often for pennies on the original MRSP dollars. Brands like Acopian, Allen Bradley, TDK/Lambda, etc.
