Here it's nothing much but Cuba. Every blue moon, Radio Ya in Nicaragua makes it.
Hearing US stations on 600 here in south FL is a rarity....but then, I am not much of an AM DXr anymore.
Does anyone recall Cuba using Radio Moscow English broadcasts on 600 in 1980 (and maybe 1981)? I was stationed in Massachusetts at that time, and I could even hear it there. (Was stationed in Alaska the early part of '80 & my folks mailed me a news article about "Red Radio", the RM relay on AM.....No I didn't hear it from AK!)............I always wondered how Jacksonville FL's 600 fared at that time, and how the local reception was!
cd