Abstract: A method and system for injecting a pulsed radio frequency signal into a fluid-containing system in order to create and propagate an electromagnetic field throughout the fluid-containing system. The electromagnetic field may be used to prevent the formation and build-up of scale in the fluid-containing system and/or to prevent the proliferation of bacteria within the fluid-containing system. The method and system may also be used to inject a pulsed radio frequency signal at a number of points in a fluid-containing system, or to inject a pulsed radio frequency signal to a number of independent fluid-containing systems.