Can we back to communication without the internet? With RATS (Radio Transceiver System), actually, yes! You can send encrypted messages and small files from computer, but even so, data can be sent only to another computer with RATS unit.
So It’s a great investing if you like to chat with your not far away living friend and like to be kind of undercover.cool

Via RATS Kickstarter Page:

Specifications

Frequency: 420-452Mhz

Max Transmitter Power Output: 100mW | 20dBm

Modulation: FSK

Transfer speed: 2.40KB / sec

Information transfer speed: > 1KB / sec

Range: approximately 1 km with 100mW TPO in an urban area with the standard antenna. With better antennas and less obstacles in the path you can reach 5-6km.