Wellbrook ALA1530LNP HF Antenna

This antenna together with the ALA1530LN are the only 1m dia. loops in production to use an ultra low noise JFET design. The loop has recently had a significant design change to improve LW/MW and SW reception. The antenna gain is increase by 9dB and the LW and MW signal to noise ratio s/n is up to 10dB higher, with an improved s/n on the HF bands. The LW and MW 3rd order IMD is now approx. 20dB lower when compared to the ALA1530 and the ALA1530S+. This being a combination of altering the gain distribution and the lower IMD of the JFETs.
The ALA1530LNP has a noise figure of approximately 0.2dB, which give a noise floor that is 13dB lower compared to a similar gain loop with a noise figure of 3dB.
The new ALA1530LNP is the second generation of this antenna and uses 8 very high gain JFETs in parallel push-pull with a Bipolar transistor cascade stage for extended bandwidth. A very low amplifier noise floor is achieved by dynamically decreasing the JFET Source resistance to a fraction of an Ohm. This is achieved using a proven technique developed in the 1980s by coupling the FET Gate to the Source with a phase inverting transformer.

A unique 2 transformer push-pull Norton amplifier with a higher HF gain is now fitted in the Antenna Interface. MW OIP3 has been increased to +55dBm; thus giving this active antenna one of the highest third order intercept points in its class.

The amplifier is now house in a separate module, thus isolating the electronics from the mechanical stress caused by wind loading on the loop. The amplifier to loop wire terminations use tin plated silicone insulated wire and crimp terminals rated down to –40 Celsius. The module sits on of the loop box and is secured by stainless steel screws. The base of the loop is now reinforced with an acetal rod to minimized damage due to weather extremities.

This unique broadband magnetic antenna is only 1m diameter and rotatable to provide deep nulls to reject noise and interference. This new broadband un-tuned loop antenna is designed specifically to reject locally radiated and mains borne noise from TVs, computers, mains wiring etc.

The Loop antenna responds primarily to the Magnetic Field and rejects locally radiated Electric-Field noise providing far lower noise reception than active whip/dipole antennas. Compared to active whip/dipole antennas, the loop will reduce locally radiated noise by up to 30dB and mains borne noise by up to 60dB. The ALA 1530LNP has 30dB nulls to further reduce interference.

Product Wellbrook ALA1530LNP
Delivery Antenna, Power Supply, Antenna Interface
Requirement The ALA1530LNP should be positioned approximately 5m away from any buildings.
Recommended Rotor
Use cases HF reception
Training ---
Price ca. 430 €


  • Balanced low impedance Magnetic loop with enhanced performance compared to shielded and Moebius loop types
  • Ultra low noise JFET design with up to 13dB lower noise floor compared to conventional low noise and MMIC amplifiers
  • Unique two transformer Norton amplifier with a +55dBm IOP3 ensures good performance in a strong signal environment
  • Up to 30dB rejection of locally radiated and power-line noise compared to an active whip
  • Figure of eight directivity and deep nulls to further reduce interference
  • No tuning necessary or matching unit; No planning problems, works at ground level, can be camouflaged

Wideband HF Antenna

The ALA1530LNP is the high gain version of the ALA1530LN. This compact Active Magnetic loop antenna primarily designed to provide improved performance over conventional passive and active antennas.


Feature Data
Frequency range 50 kHz to 30 MHz
Loop Diameter 1 m
Power consumption 12 volts at 200mA
Amplifier Intercept point typically (MW Band) OIP2 +90dBm, OIP3 +55dBm
Amplifier Noise Figure Approx. 0.2dB
Output impedance 50 ohms BNC
Max. Field strength 400V/m or 1.0A/m pulse