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 AX-17C 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.
The AX-17C antenna is 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.
The antenna is 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.
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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. |
