How can I maintain contact with mobile person

[NorthernRaider]

(3 September 2013, 13:24)Steve Wrote: My retreat is 300 miles from where my sons and their families live, there may come a time when they need to make that trip in difficult conditions, perhaps with limited fuel or with vehicles blocking roads. I would like to keep track of their progress in case I have to meet them half way to help them in.

How would you keep in touch ? Comms will need to work at every point in the 300 mile trip, not necessarily whilst mobile so a big aerial is acceptable as long as it can be collapsed for transport.

Your asking TWO questions steve
First you say " I WOULD LIKE TO KEEP TRACK OF THEIR PROGRESS"

Then you ask " HOW WOULD YOU KEEP IN TOUCH?"

LS and tothers are right about radios for the second question but for the fitst you can get doofahs called APPS for cellphones that turn them into GPS trackers, they were developed to help parents know where their children are at all times, you can tap into their cell phones remotely and it gives you their exact real time location.
Obviously if the cell towers are out it wont work.

Alternately if you have the money get em an irridium satelite phone.