Hi all I've recently learned about PLBs and EPIRB, which basically send distress signals with position information from the device built-in GPS. They can be relatively expensive, so I'm wondering if anyone has made any work towards a home-brew device? Legal Disclaimer: haha, homebrew is a poor term. These devices need to be registered etc., so it's not recommended (and actually unsafe) to build your own device. What I'm looking for is education on how these things work and general pointers on how to approach the designing of such a device. Thanks!