ALA 1530 (OUTDOOR) and ALA
2000 (INDOOR) BROADBAND ACTIVE
LOOP ANTENNAS 150kHz to 30Mhz
NEW ALA 1530+ Upgraded Version NEW
The ALA1530 is a compact Active magnetic loop antenna primarily designed to provide improved performance over conventional passive and active antennas. This loop has been production for over 10 years and has recently had significant design changes to improve LW and MW reception.
This Active loop sets new standards for the listener. For the first time it is possible to reject locally radiated and mains borne noise and still provide improved sensitivity compared to larger antennas.
1m dia. Aluminium loop is designed for outdoors, even
at ground level. The loop has a frequency range from 40kHz to 30MHz and
matches directly to the receiver. The ALA 1530 is probably the only Commercial
Active antenna available to the Radio Enthusiast to provide directional
reception of the LW and MW bands.
Supplied complete with Antenna Interface and a regulated power supply.
BROADBAND LOOP FEATURES
LOOP ANTENNA ADVANTAGES
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.
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 ALA 1530 Broadband Loop has been specifically designed to reduce intermodulation products to a minimum. The second order and the third order intercept points are typically +70dBm (IP2) and +40dBm (IP3) respectively. Thus the level of the intermodulation products are generally below the atmospheric and man made noise.
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 ALA 1530 should be positioned approximately 5m away from any buildings.
ALA 1530+ Upgraded Version NEW
N.B. The Antenna Interface is not used with the ALA 2000
ILLUSTRATION OF THE HIGH ELECTRIC FIELD COMPARED TO
N.B. The Loop nulls will also further reduce interference by up to 30dB.
An active whip or dipole antenna will also pick up high levels of interference.
ALA 1530 Calibration Chart .pdf file (fast download)
by kind permission
May 1999 - Paul Beam
Nov 2000 - John Wilson
Apr 2001 - John Wilson
Nov 2001 - John Wilson
K9AY - Oct 2002 - John Wilson
Medium Wave Circle
Intermodulation - further explanation (should you want it!)
Willi Passman's Media Consulting
Werner Funkenhauser's Whamlog Pages
HamRad - Amateur Radio Operator's Guide to manufacturers,
dealers and organisations, as well as the home of the HamRad Trader.
Specialists in Broadband Loop Technology!
Designs and specifications are subject to change without notice
Copyright Wellbrook Communications