I guess we've pushed this thread as far as it will go for now. @Snake_Doctor, we understand your intent and aim for short range, emergency communications, and have tried to steer you toward something potentially useful. Packet radio just ain't it.
ROS is a weak signal digital mode that now has randomized FHSS capability, similar to CDMA phones (ROS v7.2.7 | Weak signals Radio Chat something that might be useful for monkey business once FCC regs no longer matter.
No offense, but you'd need to know one other, very important thing: if they were able to receive and send unencrypted transmissions. Most USFS Ranger radios are equipped for "P25" digital encryption, and most are set up to use it by default, so even if they've been optioned to allow automatic reception of unencrypted transmissions (that's John Q. Public, busted up and calling for help), they will probably require the ranger to turn off P25 before answering, and that means confusion, uncertainty, and wasted time. Sorry to bear bad news, but I think it's unproductive to plan on making emergency calls to stations where the people don't know you, aren't used to such traffic, and might have to RTFM before they can answer en clair - assuming that they were not very busy, overwhelmed with conflicting demands, or trying to triage existing problems that came through their usual chain of command. There's no magic bullet when it comes to radio: being prepared to make a call for help means being part of a network that expects such calls, is able to deal with them effectively, and which will be available when the cellular networks are overloaded and/or running out of battery charge. I recommend that those who want Emcom capability join a local ham radio club, get a license, and become a part of the solution for the other guys whom are busted up and calling for help. William Warren
