http://en.wikipedia.org/wiki/Maidenhead_Locator_System
http://qthlocator.free.fr/index.php
http://www.sarl.org.za/public/QRA/Abt_Locators.asp
The file ZS-WAGS.GPX file can be uploaded to any Garmin Map enabled GPS. Follow the link with thanks to Pierre ZS6A. https://drive.google.com/file/d/0BwxhBtZxalIfZ0ZZLUpjcGxCeGM/view?usp=sharing