Also look into the sibling comments about Ham radio. The lowest class license is really easy to get and gives you pretty wide permissions on various bands.
I got my General class license for ham a couple of years ago, and it's a fun hobby that does lend itself to disaster preparedness. My sub-$1000, battery-powered HF setup easily allows me to reach out and make contact across most of North America, and I frequently make contacts in Japan, South Korea, and eastern Russia. And with my cheap Baofeng and AnyTone radios I can tap into the awesome regional repeater network we have here in the Puget Sound.
However, with those radios I can only talk with other hams. In contrast, my $75 for 10 years GRMS license allows my entire family (the rest of which are not licensed hams) to talk on GRMS channels at up to 50 watts, instead of the 2 watt max you have with FRS. And here in Seattle we get access to some awesome GMRS repeaters, so we can basically communicate with each other anywhere across the city.
Can one antenna and one device do all this and you can switch between HAM and GMRS or you need multiple devices?
These are FRS radios, which share channels with GMRS but are not capable of txing on GMRS-only bands, repeater use, or higher output.
That said, get a GMRS license. $70 (soon to be lowered) for 10 years, and no test required.