General Dynamics upgrading Navy shipboard radio with long-range HF automatic link establishment (ALE)

May 26, 2016
SAN DIEGO, 26 May 2016. Military radio experts at General Dynamics Corp. are upgrading the U.S. Navy AN/USC-61(C) maritime radio system to high frequency (HF) capability, as well as automatic link establishment (ALE) to enhance shipboard over-the-horizon communications.
SAN DIEGO, 26 May 2016. Military radio experts at General Dynamics Corp. are upgrading the U.S. Navy AN/USC-61(C) maritime radio system to high frequency (HF) capability, as well as automatic link establishment (ALE) to enhance shipboard over-the-horizon communications.

Officials of the U.S. Space and Naval Warfare Systems Command (SPAWAR) in San Diego announced a $7.3 million contract modification Wednesday to the General Dynamics Mission Systems segment in Scottsdale, Ariz., to update to the DMR software to add HF and ALE capabilities.

The General Dynamics AN/USC-61(C) shipboard radio enables surface ships and submarines to communicate over high frequency (HF), ultra-high frequency (UHF) line of sight, UHF satellite communications (SATCOM), and very high frequency (VHF) radio bands.

HF radio operates on frequencies between 3 and 30 MHz using radio waves that can bounce off the ionosphere layer of the Earth's atmosphere to achieve long-range communications. HF also is capable of line-of-sight communications, as well as ground-wave over-the-horizon communications.

Using HF can be tricky, however, because changes in the ionosphere can cause RF interference and communications dropouts. HF radio also is particularly susceptible to interference from lightning storms, and propagates differently in the daytime, at night, and during the different seasons.

Related: U.S. Coast Guard adopts Thales HF-ALE radios for surface ships

Automatic link establishment seeks to overcome some of these deficiencies by enabling radio operators automatically to choose the best HF frequencies on which two stations or a network of stations can transmit and receive.

ALE is the de-facto worldwide standard for initiating and sustaining HF communications for voice, data, text, instant messaging, internet messaging, or image communications.

ALE alerts radio operators audibly and visually so they can begin communicating with each other immediately, and helps eliminate the longstanding need for repetitive calling on pre-determined time schedules and monitoring static on HF radios.

An ALE-equipped radio uses a callsign or address in an ALE controller, which constantly scans through a list of frequencies listening for other ALE radio callsigns. To reach a specific station, the caller simply enters the callsign just like dialing a phone number.

The ALE controller selects the best available frequency and sends out brief digital selective calling signals containing the callsigns. When the distant scanning station detects the first few characters of its callsign, it stops scanning and stays on that frequency. The two stations' ALE controllers automatically handshake to confirm that a link is established and they are ready to communicate.

Related: Military HF radio communications may prove effective for Internet relay chat in land, sea, and air applications

If changes in the ionosphere break or interfere with communications in progress, the system quickly can re-establish communications by finding other clear frequencies.

The AN/USC-61(C) is a maritime software-defined radio (SDR) that has become standard for the U.S. military. The compact, multi-channel DMR provides several different waveforms and multi-level information security for voice and data communications.

Software-defined radio waveforms are computer programs that enable SDR-enable radios to operate on different frequency bands with different encryption and cyber security functions. The AN/USC-61(C) operates on Navy surface ships, submarines, and other military platforms using frequencies from 2 MHz to 2 GHz.

General Dynamics has certified the DMR to pass secure voice and data at multiple independent levels of security (MILS) over HF, VHF, UHF, and SATCOM channels, and to withstand the effects of electromagnetic interference and other harsh operating conditions.

Related: General Dynamics to provide maritime radios for shipboard communications aboard Navy vessels

The DMR also is certified by the Joint Interoperability Test Command (JITC) to be compliant with the U.S. government’s MIL-STD-188-181B/182A/183A requirements for UHF SATCOM.

General Dynamics built the AN/USC-61(C) using open-architecture standards. The radio includes Embedded type 1 encryption; embedded red/black baseband switching and routing; co-site performance; reduced manpower requirements; single point of control for HF/VHF/UHF/SATCOM radio communications; and built-in test (BIT).

General Dynamics won a $12.9 million SPAWAR contract last month to provide AN/USC-61(C) maritime radios for Navy surface warships and submarines.

On Wednesday's contract General Dynamics will do the work in Scottsdale, Ariz., and should be finished by April 2018. For more information contact General Dynamics Mission Systems online at, or SPAWAR at

About the Author

John Keller | Editor

John Keller is editor-in-chief of Military & Aerospace Electronics magazine, which provides extensive coverage and analysis of enabling electronic and optoelectronic technologies in military, space, and commercial aviation applications. A member of the Military & Aerospace Electronics staff since the magazine's founding in 1989, Mr. Keller took over as chief editor in 1995.

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