130 grams is not very much to carry to save your life, these GPS Personal Locator Beacons look very useful: http://www.equipped.org/blog/?p=284
See also:
http://www.theultralighthiker.com/get-lost-get-found-plbepirb/
http://www.theultralighthiker.com/the-poor-mans-satellite-phone/
