The present invention pertains to a portable repeater device for use by friendly forces in a combat theater. The repeater device includes a sensor that receives an interrogator signal, coded or un-coded, from a friendly interrogator, such as an airborne attack or search and rescue vehicle, and a transmitter that transmits a coded or uncoded beacon at a covert wavelength outside the typical night-vision spectrum back to the interrogator in response. Because the transmission wavelength of the repeater signal is covert and outside typical night-vision capabilities, the system limits the ability of enemy forces to locate friendly forces employing such signaling beacons through typical night-vision equipment.