The AX-81SM antenna is a compact active LF to HF antenna, ruggedized to suit harsh outdoor environments, and particularly suitable for high performance professional and military applications. Designed for surveillance and monitoring, the antenna can be useful anywhere where good performance and reliability are required, and where space is at premium.The receive-only antenna covers the frequency range of 20 kHz to 30 MHz, or 10 kHz to 50 MHz with somewhat reduced (but still excellent) performance.While designed to be entirely general-purpose, the AX-81SM antenna is especially suitable for the WiNRADiO G313e and G313i range of receivers.The principal elements of the antenna are constructed of a low-carbon austenitic stainless steel that contains molybdenum. Austenitic (chromium and nickel content) stainless steels have high ductility (i.e. ability of a metal to plastically deform without breaking or fracturing), low yield stress and high ultimate tensile strength, when compared to a typical carbon steel. The 316L grade as used for the AX-81SM antenna also offers an especially high degree of resistance to corrosion. The choice of materials and the durable construction of the AX-81SM antenna will ensure trouble-free operation for many years.Internally, the antenna features excellent protection against electrostatic discharge, its input automatically grounded when the antenna is not in operation (i.e. power is not applied to the antenna).