Get your ham radio license, and you can use WinLink and APRS over HF radio. Winlink is a packet radio email system. APRS is a global positioning & information service that can be accessed over HF radio. Both are free to use, worldwide, and can help supplement your personal safety.

http://www.winlink.org/
http://aprs.org/

There are a number of low power radios. Yaesu makes some tiny, popular HF radios like the FT-857 & FT-817. Both radios can run off of battery packs.
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John Beadles, N5OOM
Richardson, TX