All of the listed "channels" in the drop down boxes are Text only channels.
Squad, only those in your squad can see them
Country, only those in your country can see them
Mission, only those who have joined a posted mission can see them
All, everyone from all countries can see them. (im not sure but the "all" may be disabled in the melee arena. To text to everyone you have to tune 200)
The channels, 1-199 are only your country can use them. Channels 200+ are cross country channels so you can tune players on other countries.
Channel "V" is the Vox channel and the channel numbers and labeled channels (in the drop down boxes) have the same setup as the text channels.
SIk1 explained the range channel.