Past, Present and Future of Tactical Radios – Part 9

In the last installment, I introduced the first generations of SINCGARS radios, but left off with mention of the System Improvement Program (SIP) and Advanced SIP (ASIP) generations.  If one considers the PRC-77 based on internal improvements to the PRC-25, then perhaps the SIP and ASIP are analogous evolutions from the original SINCGARS.

After Desert Storm, Army planners realized further battlefield digitization was inevitable.  Through the early 1990s Army Communications-Electronics Command (CECOM) began programs to introduce near and long-term solutions to meet the digital requirements.  At the time, the tactical Army relied heavily on an integrated data-voice network from the maneuver brigade up to the theater level.   Mobile Subscriber Equipment (MSE), at division and corps level used packet switching to pass, what was for its time, high-speed data.  These formed the backbone of the Army’s first Tactical Local Area Network (TACLAN).

The “must have” application for brigades and above in the post-Gulf War was imagery, particularly from the much ballyhooed Joint-STARS.   But planners also recognized the need for more than intelligence products at the foxhole level – particularly friendly forces information, general situational awareness, logistics reporting, and digital supplements to field orders.

The problem was the hardware between brigade and battalion.  Maneuver battalions typically possessed two AN/VRC-97 Mobile Subscriber Radio Telephone (MSRT) tied into the MSE network.  MSRTs were ungainly – sort of a cell phone the size of the old VRC-12 radio.  Battalions often paired MSRTs with an AN/UXC-7 Lightweight Digital Fax, which weighed 55 pounds (“lightweight.” I’m not making this up!).  Clearly not an option for the front line.

Also in limited service was the Enhanced Position Location and Reporting System (EPLRS), providing “friendly forces” tracking using a set of digital radios, both vehicle mounted and backpack.

EPLRS Radio Set

Although not a true combat net radio, but in scope of this discussion, EPLRS offered a 56 kilobyte-per-second (kb/s) network for data traffic (again, state-of-the-art at the time).  With a data cable, an operator with a laptop could send and receive data.  The EPLRS software application displayed friendly forces within the network.  On the down side, the radio didn’t support voice traffic; weighed as much as a SINCGARS; and introduced another radio to configure.  While useful, the EPLRS was about a generations ahead of its operators in my opinion, with a steep learning curve.

CECOM concurrently worked towards the integration of SINCGARS with the MSE and EPLRS networks.  SINCGARS SIP introduced a network interface card (NIC) option.  This gave the radio an IP address (just like the computer you are reading this on) and connected to the TACLAN.  An external InterNetwork Card (INC) performed routing functions between SINCGARS, EPLRS, or MSE networks.  In operation, a SINCGARS on a vehicle mount used an INC to connect to either EPLRS or MSE.  That radio set became the “gateway” for other SINCGARS, even PRC-119s, and computer terminals (imagine a big, fat 1990s era laptop) connected by data cables.  Although the data rate remained at 19 kb/s.  In 1995, CECOM demonstrated this setup as part of “Force XXI,” with a team in the field at Fort Gordon passing an email through SINCGARS to a garrison terminal at Fort Monmouth.   And, no it was not a PowerPoint attachment!

SINCGARS SIP, designated RT-1523C or D, were externally similar to the second ICOM sets.  The SIP also introduced an interface to the standard Precision Lightweight GPS Receiver (PLGR) devices, and allowed the radio to pass its position to other stations in the network, thus making SINCGARS a “poor man’s” EPLRS.  Further, the GPS provided a handy time source to resolve continuing time drift issues.

Keeping with the ever evolving electronic technology, the next upgrade for SINCGARS featured a digital signal processor further reducing the physical size of the radio. Although I’ve never seen it stated in such terms, the ASIP in some regards answered a pressing need (once again) for squad level radios.  Ever since the introduction of frequency hopping radios, the old single channel PRC-126s’ days were numbered.


The radio, designated RT-1523E, weighed 9 pounds even with battery, handset, and antenna.  Even at half the width, the ASIP fits the older SINCGARS mounts.  Note the large side panel on the photo above, which is the compartment for a BA-5590 battery.


But the “time drift” issue remained.   The official solution involved a new fill device.  In the mid-1990s the Army began introduction of the AN/CYZ-10 ANCD (or “crazy ten”) device to replace the various fill devices (KYK-13 being the most familiar).

The "Crazy Ten" ANCD

The ANCD, with all those buttons and tiny display, carried all five variables (and more), including time, needed for SINCGARS operations.   I’ll be blunt in my assessment – the initial fielding was rushed without proper training and the devices were complex in operation.  The “crazy ten” worked, but I spent many a tense moment trying to figure out what button I’d skipped around COMSEC change over time.

In 2001, the US Army and Marines had the best system of combat net radios in the world, particularly considering the digital capability.  Trouble was, the system was designed around a conventional war to match up with conventional threats.  The asymmetrical wars in Afghanistan and Iraq brought requirements unseen by the original SINCGARS requirements.  The adversary lacked sophisticated jamming and intercept capabilities, rendering some of the radio’s features unnecessary.   Yet, the warfighter needed more support for data traffic than ever imagined.  In a war where routine patrols could become front page news within hours, rapid dissemination of information was paramount.

A senior communications officer once confided that OIF and OEF are “bring your own damned radio” wars.  With the distinction between conventional and special forces blurred, many new radio types arrived in line units. Many “limited procurement” radios found their way into the combat zone.  Commercial “fill in” (or COTS) products abounded.  In the remote areas, regular infantry squads used single channel satellite radios (practically unheard at that echelon before 2001).  Partly addressing the needs, the AN/PRC-117 multi-band radio appeared in significant numbers.

PRC-117 in TACSAT Mode

The PRC-117 offered capability to operate with SINCGARS FH nets and single channel satellite nets.  As seen in the photo above, the set is about the same size and weight of a PRC-119.  And somewhat a glimpse into the future, the PRC-117 is a “software-defined” radio.

In retrospect, while many (including me) have cursed SINCGARS for its complexity, the radios have proven adaptable and reliable.  Over the years, better training programs have resolved the complexity issues somewhat.  The system has served through a transition from “voice-centric” radio nets to a time of “data-centric” computer networks.  For what it is worth, the VRC-12 and PRC-77 family served as the primary US Army radios from 1965 until about 1992 – some 27 years.   SINCGARS took over that role starting 1990 and is still going strong at 20 years with no replacement in sight.  Current plans call for over 400,000 SINCGARS remaining in Army inventories out to 2028.

In the last post in this series, I will summarize 70 some odd years of combat radio development and offer my thoughts about what could and should be done for the future.

2 thoughts on “Past, Present and Future of Tactical Radios – Part 9”

  1. ASIPS is a great improvement, but I miss the ability to change channels by just, well, twisting the knob. My drivers can generally do it by touch, but I hate twisting and contorting behind the radio to see the display and then punching through it with buttons. With SINCGARS, I was very particular about loading primary, higher, subordinate main effort, fires, MEDEVAC and jump/alternate nets in channels 1-6 and could switch in seconds.

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