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AX-81SM Active LF-HF Antenna

Product.Nr.: 9234-M

product description

AX-81S Active HF Antenna

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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 G3 range of HF receivers including the G31DDC, G33DDC, G35DDCi, G313, G33EM.

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).

Recommended accessories
  • WR-AC-RMB-114 heavy duty rail-mount antenna base has a single swivelling mount. It accepts any standard antenna with a 1" diameter standard #14 thread (such as the AX-81S antenna) and can be mounted on a railing of 7/8 to 1" diameter. Material is stainless steel 316 grade.
  • WR-AC-DMB-114 heavy duty deck-mount antenna base has two swivelling mounts for complete adjustability. It accepts any standard antenna with a 1" diameter standard #14 thread (such as the AX-81S antenna). Material is stainless steel 316 grade.
  • WR-CMC-30 Common-Mode Choke eliminates common-mode noise from the antenna feedline, resulting in a considerable increase of the received signal quality. Common-mode noise is generated by computers and other electric or electronic appliances, and can be a problem especially in the lower portions of HF spectrum. The Common-Mode Choke can be also very useful to provide an alternative earthing point if the AX-81S antenna itself cannot be grounded due to its location, or its ground connection is inadequate.
  • WR-BT-650 Power Injector (Bias "T") provides a means of injecting DC power in a coaxial cable, to power the antenna from a remotely located power supply. It features a flat frequency response and low insertion loss. Note that the Power Injector is not required if the AX-81S antenna is used with the WiNRADiO G33EM receiver which already provides suitable power for the antenna at the receiver's antenna input. For other applications, it is recommended to use WiNRADiO SF-41 range of low-noise power supplies.

Technical Specifications