I assume you mean channels 101-299. In which case no, there is no way of knowing except to tune to the channel and check it yourself. Even then give it a week or 2, as a squad may be using it but they just get on the game on weekends. And, even you find an open channel on one certain country, it may be in use on a different country if/when you change.
However, a squad will always have it's own personal squad channel that can not be tuned to from some one outside of the squad.
Lambo