Indoor Active HF Antenna (AX-17C)



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SKU: AX-17C Category:


The AX-17C is a miniature indoor active HF antenna suited for applications where it is not possible to use conventional large outdoor antennas, and where loop antennas are either not available or not practical due to their large size.

The antenna is by no means intended to replace “proper” HF antennas, certainly not for long-distance (DX) applications. However, it will provide very acceptable reception where space is at premium, and where the signal is relatively strong.

It’s also suitable in conditions where much interference exists in the electric component of the electromagnetic field, for example in high-rise office or apartment buildings, and reception of the magnetic component only improves the signal-to-noise ratio. Furthermore, the antenna’s directionality makes it possible to reduce interference by rotating the antenna away from the interference source. Its small size makes it easily portable and useful for covert or mobile applications.

The antenna is constructed using a special type of ferrite material combined with a unique active circuit which maximizes sensitivity and minimizes overload from nearby strong signals. It’s powered using a linear 12 V AC/DC adapter which is supplied as part of the package.

The antenna covers the frequency range of 0.1 to 30 MHz. It is optimized for mainly HF use, with reduced performance under 2 MHz, where stronger local signals are expected.

While designed to be entirely general-purpose, the AX-17C antenna is especially suitable for the WiNRADiO G3 Series of receivers. However, it will work well with most third-party receivers with 50 Ohm antenna input impedance.

The antenna comes fully assembled. Installation involves only two simple steps: Connecting the antenna to the receiver via the supplied coaxial cable; and powering it up using the supplied power adapter. Upon activating the front-panel push-button switch, the front-panel LED indicates that the antenna is powered up.

The optimum location of the antenna should be found by trial and error. Typically it would be close to a window, away from potentially interfering devices such as a personal computer. In most cases, the antenna will exhibit directivity (this may vary depending on how the received signal propagates) and optimum reception can be found by rotating the antenna.

An altogether different and interesting alternative to this antenna’s typical usage is as an inductive coupler to an outdoor long-wire antenna. This is accomplished by winding a few turns of insulated lead-in wire around the AX-17C antenna’s body, with the other end grounded. The purpose of such an arrangement is to eliminate common-mode interference caused by ground loops resulting from a galvanic connection of the outdoor antenna lead directly to the receiver. The optimum number of turns should be established experimentally; typically this will be between one to five turns.

Technical Specifications

•Type: Active ferrite antenna
•Pattern: Directional
•Usage: Receiving only
•Frequency Range: 0.1 to 30 MHz
•Output Impedance: 50 Ohm
•Supply Voltage: 12 V DC (min 10 V, max 14 V)
•Supply Current: 50 mA typ. @ 12 V
•Connector: SMA female
•Dimensions Length: 164 mm (6.5″)
•Width: 96 mm (3.8″)
•Height: 21 mm (0.8″)
•Weight 233 g (8.40 oz)

Power Adapter (included)
•Model: WiNRADiO SF-41 Linear-mode regulated AC-input DC-output power supply
•Input voltage US version: 110-130 V AC, 60 Hz
•EU version: 210-250 V AC, 50 Hz
•AU version: 210-250 V AC, 50 Hz
•JA version: 90-110 V AC, 60 Hz
•Output voltage 12 V DC ±5%
•Output current 200 mA max
•Thermal fuse 130°C
•Input socket US version: integral cord
•EU version: IEC-320 socket
•AU version: IEC-320 socket
•JA version: integral cord
•Output socket: Standard jack OD = 5.5 mm, ID = 2.1 mm, positive tip
•Noise: < 40µV (10 Hz <= f <= 100 kHz)
•Size: 70 x 46 x 41 mm (2.8 x 1.8 x 1.6 in)
•Weight: 320 g (11.3 oz), including cord

Cable (included)
•Type: RG-58U
•Length: 1.2 m (4 ft)
•Connectors: SMA male (both ends)

Specifications are subject to change without notice due to continuous product development and improvement