Life in the Old SINCGARS Waveform Yet!

Guest post by Dr. Thomas Withington

Despite being over 30 years old, the SINCGARS tactical radio system is enjoying a new lease of life via a modernisation.

Legacy RT-1523 series SINCGARS radios can be seen here on top of the central console of this US Army AM General High Mobility Multipurpose Wheeled Vehicle. Image – RT-1523 SINCGARS (US Army)

The Single Channel Ground and Airborne Radio System, better known as SINCGARS, was revolutionary when it graced the battlefield in the early 1990s. Initially adopted by the US armed forces, SINCGARS would equip scores of NATO (North Atlantic Treaty Organisation) and allied nations around the world. SINCGARS radios were designed from the outset to resist jamming. They provided interoperability between ground, naval and airborne units equipped with SINCGARS radios. SINCGARS also replaced a multitude of disparate Very High Frequency (VHF) Frequency Modulation (FM) radios used by the US armed forces writ large. FM ensured that transmissions were clearer than other forms of modulation thanks to comparatively less interference. FM sets also used less power compared to their amplitude modulation counterparts. This helped extend battery life and made the radios safer for troops to use.

SINCGARS radios were produced in backpack, vehicular and airborne configurations. The radios’ waveforms could carry data and voice traffic. They had integral Communications/Transmission Security (COMSEC/TRANSEC) protocols such as frequency-hopping. SINCGARS used a bandwidth of 30 megahertz/MHz to 87.975MHz. Each channel was 25 kilohertz wide. SINCGARS’ resulting 57.975MHz VHF bandwidth could support a staggering 2,319 channels. Although thin by today’s standards, SINCGARS handled data at rates of from 600 bits-per-second up to 16 kilobits-per-second.

SINCGARS was first deployed in small numbers with US forces supporting Operation Desert Storm in 1991 which liberated Kuwait from Iraqi occupation. As official US government documents show, only one battalion from the US Army’s 1st Cavalry Division was equipped with SINCGARS at the time. Since then, SINCGARS has become ubiquitous throughout NATO and allied nations. In the wake of Russia’s invasion of Ukraine in 2014, the US government began shipping L3Harris RF-7800V Falcon-3 radios to the Ukrainian armed forces. These radios were equipped with the SINCGARS waveform. The Russian Army deployed robust electronic warfare (EW) capabilities into the Ukrainian theatre of operations from 2014. These included several systems designed to detect, locate and attack very/ultra high frequency (V/UHF) tactical radios and networks. For example, the RB-301B Borisoglebsk-2 combined EW system and the RB-531B Infauna and R-330Z Zhitel EW platforms are used at the tactical level by Russian maneuver formations. They perform V/UHF communications intelligence collection and communications jamming. Despite these capabilities, Ukrainian Army sources have told the author that the army’s SINCGARS radios have not suffered adversely from any jamming.


SINCGARS’ integrity was a strong endorsement of the system’s robustness. Nonetheless, the US Army’s Programme Executive Office for Command, Control, Communications-Tactical (PEO-C3T), SINCGARS’ custodian, is not resting on its laurels. SINCGARS is receiving a new lease of life thanks to a modernisation effort the PEO-C3T began contemplating in 2017. This resulted in a request for information published by the office in September 2017 concerning a SINCGARS modernisation. Mindful of the jamming threat from near-peer adversaries, the army wants to modernise SINCGARS’ COMSEC/TRANSEC. Reports stated this will roll out Advanced Encryption Standard-256 (AES-256) attributes. AES-256 encryption will adorn the SINCGARS fleet of vehicle and backpack radios. AES-256 is the preserve of the US National Security Agency (NSA). Considered one of the most secure encryption standards and routinely used for Top Secret traffic, AES-256 is so called because of its 256-bit key size. A one-bit key size has two possible combinations. A two-bit key size has four possible combinations. A 256-bit key size has 1.1 x 1077 possible combinations. It is considered practically unbreakable using current levels of computing power.

Paul Mehney, director of public communications at the PEO-C3T, told the author that “the SINCGARS waveform modernisation includes enhancements to both electronic warfare protection and voice quality.” He continued that the upgrade will see the army develop the final SINCGARS software to this end. Once this is done, functional software qualification testing will be performed by army laboratories. The waveform will then be delivered to the US Department of Defence’s Joint Tactical Network Centre (JTNC). The JTNC is the DOD’s communications waveform custodian. Once there, the JTNC will perform additional tests before placing the waveform into its repository ready for use. As highlighted below, the improved SINCGARS waveform will equip legacy as well as new radios. It will also be made available to non-US SINCGARS users, Mr. Mehney continued.

The Future

The CNR transceivers being developed by Thales and L3Harris form a major part of SINCGARS’ overall replacement in the US military. The Combat Net Radio forms part of the US armed forces’ HMS initiative. Image – Thales

Despite this modernisation, the waveform is headed for retirement. Over the long term, SINCGARS will be replaced by the new Combat Net Radio (CNR). The CNR is being developed by Thales and L3Harris. A written statement supplied by Thales said the CNR will replace over 300,000 RT-1523 series legacy radios. These formed the hardware element of the SINCGARS architecture. The CNR single-channel voice and data radio forms part of the overarching HMS (Handheld, Manpack, Small form factor) initiative. HMS is rolling out new radios to equip the army, Marine Corps, navy, air force and Special Operations Command. Both the backpack and handheld Leader radios are in production. The Leader radio is a two-channel system. It lets a Brigade Combat Team company or platoon commander communicate with their own echelon and upwards. The CNR is a single-channel system for intra-unit communications. Both the Leader radio and CNR will host the SINCGARS waveform. This will be imperative to ensure that units that have not yet transitioned to new waveforms can still communicate with those that have. SINCGARS will be replaced in US Army service by Trellisware’s TSM waveform and the Soldier Radio Waveform. According to Mr. Mehney, the army will receive its first CNRs in 2024.

By the time it retires, SINCGARS will have enjoyed an illustrious career. While it has numerous battle honours, its resilience in the face of Russian EW in Ukraine is testament to its efficacy and resilience. It will probably remain in service with US allies for many years hence, and will doubtless continue to deliver results.


Dr. Thomas Withington is an award-winning analyst and writer specialising in electronic warfare, radar and military communications. He has written widely on these subjects for a range of specialist and general publications. He also works as a consultant and adviser in these areas for several leading government and private sector clients. Furthermore, Dr. Withington provides regular commentary on security and defence aspects of electromagnetic spectrum use for major media organisations around the world. @tomwithington

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