I use this RADIOSHACK NOAH WX ALERT RADIO wired into the 12VDC using one of those multiple tap DC power plugs. Think this one needs 6VDC to operate. I went for the cheapest one I could find and this Radio Shack model 12-260 fit the bill for me just perfect. It is nice and loud when the alerts are set. It does have auto search for the closest NOAH transmitter when you first turn it on. Since you are moving around the country the specific COUNTY ALERT feature becomes useless..
Works good in my off-road POPUP trailer. I have it permanent mounted on the side of the fold-over sink setup. You need to know about the approaching winds when staying in the woods in one of these... All I do is re-power the unit when we setup and it finds the closest NOAH WX ALERT station.
Roy Ken