This plan was implemented to reduce the amount of interference between repeaters utilizing the same frequency, as well as adjacent frequencies. While these tones are not mandated, these tones have been selected so that a "common" CTCSS is available in each geographic area of Indiana. This way, repeater users know the "most likely " tone to use in a particular region of Indiana.
© 2011 All Rights Reserverd. Contents by W9MAR Amateur Radio Group.