Finally got around to making an account here too, to maybe help answer some questions.
I guess I'll get right on it too:
By default TFR (re-)spawns every squad leader with a long range radio backpack (NOTE: it doesn't matter what class you picked; if you are first to join in your squad you get the radio), dropping your current backpack on the ground.
This can be quite annoying, if you're not actually using long-rage radio in the current mission, so the first option in the dialog was made to toggle this feature of TFR's on or off.
The second and third option control wether you (re-)spawn with a random frequency on your radios (TFR default) or with the ones we use in our clan (31 for short range, 51 for long range).
I hope that answers the question.
Addendum: To restate what chessmaster already said: This module is still WIP, so the way it works will be changed at a later date.
