On Sunday, July 12, 2015 at 10:30:45 AM UTC-4, Cursitor Doom wrote:
On Sun, 12 Jul 2015 06:21:15 -0700, John-Del wrote:

If the supply is rated at half amp at 12V, a 27 ohm 10 w resistor will
give you a better idea of the supply.

I used 47R because it gives rise to half the rated output current, which
I thought would be about right for a conservative design POV. No decent
designer, surely, is going to specify a 500mA PSU for a load requiring
500mA of current. Absolutely maxed-out!


Yeah, but you're missing the point. An unregulated wall wart is rated for the max current that the supply will output no less than 12V.

If your radio has regulators inside that can handle an input of 19.33 volts, then there's no problem. If the radio was designed to run on batteries and/or a regulated supply, then you should definitely go to a regulated supply, or add a post regulator to the wall wart.