CB and HAM radios....
Smoke signals...
Text message...
CBs is what I was thinking too. (our ranch trucks have them).. In the hill country (all throughout the wonderful USA), there isn’t always cell reception. .. (even with that group of people who follow around those phone users on tv .. They never seem to make it into the hills) .. anyway, there are a lot of us who don’t have cell phones .. much less blackberries. (wait! late summer we have great blackberries growing down by the creek!! ).. ah well.. you can see why we’re thinking “CB”.
.. what channel?
People still buy CB radios? Really?
In rural areas some portable 12v. low-wat variable-frequency FM transmitters could help fill in some gaps. I’m talking about actual “suitcase” radio stations. Less than $1,000 if you hunt sources. I’ve got two “suitcase” transmitting stations that ran me about $2,500 each, but those are up-scale.