Small Box, Big Difference

Sagetech’s recently-certified MX12B IFF transponder is specifically designed for Group-II/III UAVs weighing 190 grams but boasting 500W of power.

Sagetech announced on 9th February that the firm’s new MX12B IFF transponder has been certified by the US Department of Defence.

The MX12B micro Mode-5 Identification Friend or Foe (IFF) transponder is the size of a cigarette packet and weighs a mere 190 grams (6.7 ounces). Mode-5 is the militarised version of the civilian Mode-S Air Traffic Control (ATC) Secondary Surveillance Radar (SSR) protocol entering widespread service around the world.

A Mode-S transponder outfitting an aircraft will squawk a reply to an interrogation giving details of the aircraft’s identity, a unique numerical address that the aircraft will keep throughout its life, along with its altitude, speed and heading. The key difference between Mode-S and Mode-5, which is becoming the standard NATO (North Atlantic Treaty Organisation) and allied IFF protocol, is that the latter is encrypted.

Mode-S is an integral part of the global Automatic Dependent Surveillance-Broadcast (ADS-B) ATC system which uses an aircraft’s GNSS (Global Navigation Satellite System) to determine its position. This information is continually transmitted on a frequency of 1.090 gigahertz by the aircraft to air traffic controllers and other aircraft nearby. This allows the aircraft’s location to be determined without recourse to radar.

Alongside the military Mode-5 protocol, the MX12B transmits civilian legacy Modes A, C and S data to ATC SSR collecting data on an aircraft’s identity.


Tom Furey, Sagetech’s chief executive officer, told Armada that the firm has previously supplied thousands of transponders to NATO and allied customers since 2014. These equip mostly Group-II and Group-III Uninhabited Aerial Vehicles (UAVs).

According to US Department of Defence definitions, Group-II UAVs typically have a Maximum Take-Off Weight (MTOW) of between 21 pounds/lb (9.5 kilograms/kg) and 25lb (55kg), with a 3,500 feet/ft (1,066 metres/m) flight ceiling. Class-III UAVs have a MTOW of under 1,320lb (600kg) and a flight ceiling of 18,000ft (5,486m).

The new MX12B was certified by the US DOD’s AIMS (ATC Radar Beacon System, IFF, Mark-XII/Mark-XIIA, Systems) programme office at Robins airbase, Georgia. The office is responsible for all IFF systems acquired by the DOD. Mr. Furey continued that the system complies with NATO’s Standardisation Agreement 4193 which covers requirements for NATO IFF systems.

He revealed that the company has already won undisclosed customers for the MX12B and has begun shipping systems.

by Dr. Thomas Withington