Hab ich grade gefunden und ist mit 111 Euro für ein Sender-/Empfänger Paar sicher eine sinnvolle Investition für ein Land wie die Filippinen?
Mittels Langwellensender ist man auch ohne Netz bis zu 80KM in der Lage Nachrichten an den Empfänger zu senden.
goTenna enables you to communicate without any need for central connectivity whatsoever—no cell towers, no wifi, no satellites—so when you're off-grid you can remain connected. In fact, goTenna will even work if your smartphone is in “Airplane Mode”! How does this magic work?
Pair your smartphone to your goTenna device wirelessly, using Bluetooth-LE. Your goTenna needs to be within 20 feet of your phone, so that the two can communicate with each other. Use our free app to type out a text message or share a location. Your smartphone will send the message to your goTenna, which will then shoot it out, via long-range radio waves (151-154 MHz), to the intended goTenna(s). At the other end, the exact same thing happens, in reverse: the recipient goTenna sends your message over Bluetooth-LE to the smartphone app it's paired with. All of this happens in a matter of milliseconds.