Wellbrook Communications

Active Loop Antenna LFL 1010 for long wave, medium wave and short wave radio reception. This magnetic antenna is only 1m diameter, rotatable and provides deep nulls to reject noise and interference. Ideal for users with small gardens...

LFL 1010 ACTIVE MAGNETIC LOOP ANTENNA 10kHz to 10MHz

The Active Loop Antenna is a compact antenna primarily designed to reduce local interference. It is suited to users with restricted real estate, by providing comparable performance to conventional wire antennas.

The LFL 1010 is a new LF Active magnetic loop antenna developed from the highly acclaimed ALA 1530 Magnetic loop. The LFL 1010 is primarily designed to provide improved performance compared active LF E-Field antennas.

Applications include reception of Time and Frequency stations, Sub-marine and other Military Communications, Non-Directional Aero/Marine Beacons ( NDBs ) and Longwave Broadcasting.

The Magnetic loop antenna has been recognised since the early days of LF Radio communication as the only type of antenna that affords key parameters; of directivity and rejection of locally radiated noise and co-channel interference.

Furthermore, this loop antenna has a unique property of also rejecting mains borne/power-line noise. Thus the LFL1010 will deliver a very low noise floor and provide a far higher sensitivity compared to an active LF E-field antenna. 1m dia. Aluminium loop is designed for outdoors, even at ground level.

The Loop is primarily designed for reception from 10kHz to 500kHz, with useable reception up to 10MHz.

The LFL 1010 is probably the only Commercial Active antenna available to the Radio Enthusiast to provide directional reception of the VLF and MF bands. The LFL1010 is designed to be mounted remotely from the receiver to reduce local interference.

LFL 1010 FEATURES

· Very low intermodulation ensures good performance in a strong signal environment

· Up to 40dB rejection of locally radiated noise compared to LF E-Fielde antenna

· Figure of eight directivity and deep nulls to reduce local and co-channel interference.

· Ideal for LW/MW with antenna rotator

· Rejects mains borne/power-line noise

· Rugged construction, 1.1m diameter aluminium loop, supplied with Interface and 12 volt PSU

· No tuning necessary or matching unit

· No planning problems, works at ground level

MAGNETIC LOOP ANTENNA ADVANTAGE

The magnetic Loop antenna provides far better signal quality and lower noise compared to an active E-Field ( whip ) antenna for the following reasons:

a) The magnetic Loop responds primarily to the magnetic-field, this ensures high rejection of Local Noise 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.

b) The magnetic loop is isolated from the ground and power-line earth noise. Most active E-Field antennas are susceptible to this type of noise.

c) The 'Figure-of-Eight' directivity pattern of the magnetic loop provides for a further noise reduction, an active E-Field antennas is omni-directional and so picks up more noise.

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 LFL 1010 Active 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.

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 LFL1010 is supplied Antenna Interface and a 12 volt regulated power supply. RG58C 50 ohm coaxial feeder cable is recommended for the antenna. The maximum feeder length is 100m. A 1m coax. lead connects the Antenna Interface to the receiver. The LFL1010 should be positioned approximately 5m away from any buildings.

TECHNICAL INFORMATION

Power consumption:	12 volts at 120mA
Intermodulation typically: With two signals of 30mV	2nd order -104dB 3rd order -134dB
Intercept point typically:	2nd order +70dBm 3rd order +40dBm
1dB compression point:	+25dBm
Output impedance:	50 ohms, BNC Connector

TYPICAL INSTALLATION

CONCEPTUAL ILLUSTRATION OF THE HIGH ELECTRIC FIELD COMPARED TO
THE MAGNETIC FIELD CLOSE TO A LOCAL INTERFERENCE RADIATOR

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.

LINKS, REVIEWS AND FURTHER INFORMATION

Specialists in Broadband Loop Technology!

Sales@Wellbrook.UK.com

Designs and specifications are subject to change without notice