There are a few problems with a home made Personal Location or distress beacon such as some legal requirements
If you just home brew something and begin transmitting without a proper registered identity, its going to really piss off the authorities.
They will definitely find you pretty quickly, but you may be none too happy about what they do once they have located you.
Rather like putting home made number plates on your car, or forging a gun license.
It will work very well until you are one day confronted by very angry authority.