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CommunicationsBROADBAND ACTIVE LOOP ANTENNA 50kHz to 30Mhz
The ALA1530S+ is the high gain version of the ALA1530 and the ALA1530+ Loop antennas. This compact Active loop antenna primarily is designed to provide improved performance over conventional passive and active whip antennas. This Active loop, like its ALA 1530 cousin sets new standards for the listener. For the first time it is possible to reject locally radiated and mains borne/power line noise and still provide improved reception compared to larger antennas. 1m dia. Aluminium loop is designed for outdoors, even close to ground level. The loop has a frequency range from 50kHz to 30MHz and matches directly to the receiver. The ALA series are probably the only Commercial Active antennas available to the Radio Enthusiast to provide directional noise reduction in the LW,MW and SW bands. The Loop can be mounted remotely from the receiver away from local interference. Thus ALA1530S+ generally has lower noise reception compared to manually tuned indoor loop. Furthermore, traditional wire antennas require a lot of space and can pick-up local noise. ALA 1530S+ LOOP FEATURES
LOOP ANTENNA ADVANTAGE The active antenna solves the problem of impedance matching to the feeder and yet the performance is comparable with larger antennas. However, most active antennas are the whip type and respond mainly to the electric-field. The Broadband Loop responds primarily to the magnetic-field, this ensures high rejection of nearby electric-fields. The intensity of the electric-field is usually higher than the magnetic-field when an antenna is close to interference sources such as TVs florescent lamps, mains wiring etc. Therefore, by rejecting the electric-field there will be a reduction in local interference compared to other types of active and passive antennas. Interference reduction is further enhanced by the deep nulls of the 'Figure-of-Eight' directivity pattern. INTERMODULATION Some active antennas generate intermodulation products which can appear as spurious signals interfering with reception. This interference or second order intermodulation is caused by non-linearity in the amplifier, producing signals which are the usually the sum and difference of strong Broadcast stations. The ALA1530S+ Broadband Loop has been specifically designed to reduce intermodulation products to a minimum. The second order and the third order intercept points are typically +80dBm ( IP2 ) and +43dBm ( IP3 ) respectively. Thus the level of the intermodulation products are generally below the atmospheric and man made noise. ANTENNA DESIGN The Loop antenna consists of a rigid aluminium loop
and a balanced gain optimised broadband amplifier using low noise RF power
transistors. The amplifier is encapsulated in resin and housed in a uPVC
box, this ensures reliable operation in all weather conditions. The antenna
provides low noise performance, large signal handling ability. Rejection
of mains borne noise is accomplished by using a balanced amplifier so
that the feeder does form part of the antenna return path. The ALA1530S+ should be positioned approximately 5m away from any buildings. TECHNICAL INFORMATION
TYPICAL INSTALLATION
CONCEPTUAL ILLUSTRATION OF THE HIGH ELECTRIC
FIELD COMPARED TO N.B. The Loop nulls will also further
reduce interference by up to 30dB. |
Specialists in Broadband Loop Technology!
Designs and specifications are subject to change without notice
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