The Cellular Over-the-Horizon Enforcement Network (COTHEN) is a high frequency ALE network that supports tactical long-range radio communications requirements for many agencies including Customs and Border Protection, United States Coast Guard, Joint Interagency Task Force, National Guard and other federal law enforcement.
COTHEN is comprised of land-based, fixed station and transportable transceiver systems, remote command and control systems, airborne and marine mobile systems and many special purpose ancillary systems controlled by cellular switching technology. The network is completely frequency adaptive and capable of employing voice type 1&3 encryption. The network has been refreshed and modernized in the last two years.
See below for a current list of COTHEN frequencies. As of September 2015, the network consists of 14 channels according to the Technical Service Center.
Scan 1 – 5732 USB
Scan 2 – 5909.5 USB
Scan 3 – 7527 USB
Scan 4 – 8912 USB
Scan 5 – 10242 USB
Scan 6 – 11494 USB
Scan 7 – 12222 USB
Scan 8 – 13312 USB
Scan 9 – 13907 USB
Scan 10 – 14582 USB
Scan 11 – 15867 USB
Scan 12 – 18594 USB
Scan 13 – 20890 USB
Scan 14 – 24838.5 USB