How to run 12v radio off AC current

1....Hook up your radio to a working/ running car ........reason........running is 14V not 12. Use your meter with the radio tuned to a station and producing a fair amount of volume to measure the current draw

2....When you buy a "12V" supply, make sure the current is PLENTY "headroom," double is not too much. Most of this stuff nowadays are over rated

3....Make DAMN sure the thing is about 12-14V under load. Some of these "wall wort" and other supplys marked 12V are all the way from "barely 12" to more like 18V

4...As mentioned above, NOISE. The key work here is "switching supply" AKA switcher/ inverter. ANY supply that is lightweight is a switcher. Try to get a "transformer" supply which are bigger/ heavier typically older.

Frankly I know not why you wish to do this. There is NOTHING around here on AM worth listening to for long, and darn little on FM