A new gadget can turn your cellphone in a 'walkie talkie' - even if you have no phone coverage.
The goTenna uses radio waves to communicate over 50 miles.
If both people have a device, they can messages each other and send their location, complete with a map
The gadget also creates a 'mesh' network among users, allowing the range to be extended.
The firm says the gadget is perfect for hikers and outdoor enthusiasts, and even for families who travel a lot - who can use it abroad without paying roaming charges