this post was submitted on 16 Sep 2023
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How much power does such a radio need? At what voltage (or just I and U)?
Ever since USB-C powerbanks with up to 20 V from PD are a thing, I use them for as much as possible.
How much RFI do those power banks spew out?
USB PD only goes up to 3A at 15V. That's not enough current to run a mobile radio.
A small LiFePO4 battery is a much better choice as it will supply a stable 12.8V without any switch mode supplies.
@AG7LR
@Eheran This is incorrect. USB PD does 20V 5A (100W) with the common 3.0 version. 3.1 increases that to 240W using higher voltages. https://www.usb.org/usb-charger-pd
Most radios won't run on 20V or higher. At 15V or lower, USB PD is limited to 3A.
If you wanted to get 100 watts, you would need a buck converter to step 20V down to 13.8V. Now you have two switch mode power supplies producing RFI.
I agree. Never measured the RFI since it usually replaces a cheap switchmode power supply from mains, so can only get better.