I am going to refer to the "Book of Bo-Vol I" (when I get home) and check the use of the 121.5MHz. I am thinking it was also designated as a lifeboat freq.

The "Book of Bo-Vol I" is the memo book I carried for 22 years and put down all the info I rarely used but needed immediate access to, if the need arose. From a 1/4" govt memo book, it has grown to approx 2" thick and has the Ranger Handbook attached to it, as well.

As I recall, I used to use my IFF to draw in curious DoD pilots and then contacted them on 243.0MHz to establish verbal contact, trade IFF code, then switch to a working freq and get them to give me realtime intel on where the shrimp boats were grouped/fishing within a 60 mi9le radius of my present position.

Curiosity is a powerful tool/weapon when used properly.