Here is a prepper's guide to ammunition calibers and their imperial or metric sizing.
Imagine this, it's two weeks after the SHTF and you running low on AAs and there isn't a D cell around for 200 miles without a paranoid trigger finger between you and it. Your Maglite is dead, your comms radios are about to be done, and smoke signals draw too much attention. If you haven't thought about this before, then how about now?
In this simple how to we are going to make powdered alcohol using a maltodextrin, high proof (over 125) liquor and a whisk. This is a great addition to your pack and good to start a fire as it is highly flammable. Remember: "We are not responsible for anything you do."
The mobile radio is a tried and true method for communications in the field. Modern technology has increased range and clarity while also allowing for add-ons like voice scrambling. The FCC regulates and licenses some of the more "prime" radio frequencies, but with the demise of UHF Analog Television Broadcast, there are now other frequencies that are available.