121.5 MHz is the global emergency frequency used by aviation and others. The term used is 'guard' because it's monitored by many, hence the term guard. 121.5 does not require a ham license.
WARNING & DISCLAIMER:
SELECT AND USE OUTDOORS AND SURVIVAL EQUIPMENT, SUPPLIES AND TECHNIQUES AT YOUR OWN RISK. Information posted
on this forum is not reviewed for accuracy and may not be reliable, use at your own risk. Please
review the full WARNING & DISCLAIMER about information on this
site.