Countering operational threats from in-theatre communications interference

Army, Navy & Airforce
PA Lineariser
Military radio communications
Industry / Vertical:
Homeland Security


Armed forces today need to work in a more co-ordinated way as part of effective joint operations. Communication is key to a successful operation. However, radio frequency congestion and interference is a common issue for communications in operational theatres, especially with the growing demand for high definition video surveillance feeds.

Poor quality in-theatre voice and data represents a threat to life for military personnel. At a strategic level, a military commander is responsible for several areas of operation. This requires wide-area communications with tactical commanders. At the tactical level, commanders are communicating with multiple squads to accomplish the tactical objective. This requires communications with range to reach all squads. The need for layered battlespace digital voice and data radio communications demands increasingly flexible, yet robust communications technology.

To drive radio transmission and reception, power amplifiers (PA) are deployed, but when a PA is presented with a multi-tone signal at its input, it not only amplifies the desired signal, but also generates unwanted intermodulation (IM). IM interference is caused directly by the mixing of two or more radio signals. While this mixing most commonly occurs inside the receiver or transmitter of a radio, it can also occur outside a radio in the transmission line, through rusty tower bolts or even guy lines. IM can be particularly difficult to identify, due to the large number of frequencies crowded onto a military outpost’s single antenna.

The intermodulation and non-linear distortion will increase as the PA approaches its saturation point which can become an operational weakness. To achieve the desired linearity at the PA output means the PA must be run below its saturation point. But a PA’s efficiency, calculated by its ability to convert DC supply power into RF energy, decreases as the PA’s operating point is lowered.

Congestion also increases due to the increasingly common use of COFDM HD video surveillance transmission, which needs good linearity to achieve best performance. To get quality performance typically results in extreme heat dissipation and poor efficiency. The challenge then is to maintain effective communications within a military deployment, and be able to ensure quality of transmission without adding bulk and weight to communications systems.


The Power Amplification (PA) Lineariser manufactured by Wood & Douglas counters congested radio frequencies and high levels of inference which can plague military communications. It delivers a 36% improvement in signal quality, improving performance by reducing interference levels and increasing reception, especially when airwaves are congested.

With PA Lineariser, co-located radios in the same spectrum will all perform better. By drawing 50% less power, Wood & Douglas’ PA Lineariser also dramatically reduces efficiency issues caused by heat dissipation. This enables military field communications to be designed with a smaller, lighter form factor, without loss of quality or transmission range, which delivers greater options for rapid deployment. The significant improvements to power demand also helps reduce maintenance costs and the risks associated with maintaining sites.

Mission critical communications demand clean, clear transmission and the PA Lineariser provides military personnel in-theatre with optimal transmission and reception in the most challenging signalling environments.

  • 36% improvement in signal quality despite congested bandwidths and heavy interference
  • 50% lower power demands enable development of smaller, flexible communications devices
  • Cost effective with reduced maintenance


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