Move to a country where you can legally protect yourself. Then tempt the hunter.

 

Check the offerings by Spot, maybe they have something you haven't seen before. They have devices specifically for sending SOS, and they work with satellites so no cell towers are needed. You're going to be hard pressed to hide any device where someone doing a strip search can't find it. I have a couple of the Spot Trace and if outside the batteries last months. If inside or obstructed view of the sky they can be dead in just a day or two. So keep this in mind when checking out their devices.

https://www.findmespot.com/en/index.php?cid=100

With little to no electronics experience, it's extremely doubtful that you will be able to invent something yourself. I think your only realistic option is to find something off-the-shelf and try to adapt it to your needs.

Thank you kindly for pointing me in the direction of Spot, I've looked over it previously mind - and it's certainly looks the most reliable - if hard to conceal.

I might be being daft, but I cannot see a way of deleting this thread. Is there a way I could do that?

 

Stop feeding the troll.

Bob