Reuter RLA4GS

Reuter RLA4GS HF Active Loop Antenna (el. rotatable)

The RLA4 is a broadband, non-tuned receiving antenna for the long-wave to short-wave range based on the magnet loop principle. It uses 2 loops that are arranged at an 90° angle to each other with electronically switching / rotating option of the receiving direction.

Key Facts

  • Wideband design from 20 kHz -  30 MHz
  • Reuter has a "No delivery outside the European Union" policy. Ask shoc if you need help.
  • Weatherproof version for outdoor installation with loops made of coaxial cables.
  • Remote supply and control (rotation) of the receiving direction.
  • Shielded loops
  • Quick "direction" change in about 100 ms!
  • Windows app for remote operation


The RLA4G is a cross loop receiving antenna for fixed outdoor installation. It operates broadband as a non-tuned active antenna with an integrated amplifier. The power is supplied via the HF cable. The two loops consist of coaxial cables for the symmetrical control of two differential current amplifiers with a low- impedance input. The utilization of the latest components in the two amplifier branches guarantees very low intrinsic noise values and high inter-modulation resistance. The two reception loops are arranged at an angle of 90° to one another. By adjusting the amplifiers, an electronic rotation of the receiving direction is possible. The outer jacket of the antenna elements is grounded on the amplifier housing and shields the actual loops (inner conductor) against interference radiation.
The amplifier is installed in a sealed aluminum housing. The reception diagram is then eight-shaped in the horizontal (bidirectional with 2 wide reception lobes and two sharp zeros).
The RLA4G is not suitable for direction finding. The absolute deviation of the setting compared to the actual reception direction can be several 10°s. The purpose of electronic rotatability is to ensure maximum suppression of interference signals and the cleanest possible reception of useful signals.
Power supply to the RLA4G is only possible via the HF cable ("remote power supply")


The RAP1 is an active (with amplifier) preselector for radio receivers. It provides preselection to relieve the RX from high sum voltages from wideband antennas. Receivers without sufficient selectivity and input power tolerance thus generate less IM distortion, direct sampling devices ("SDR") require less attenuation. This preselector can also be controlled from the same device as the RLA4GS antenna. Further information after testing the device.

Technical Data

Feature RLA4GS
Antenna Unit  
Frequency range 20 kHz to 30 MHz
Loop diameter 770 mm
Coaxial cable LMR-400 with RP-TNC
Power consumption  
IP2 >= +80 dBm (10.0 MHz + 10.2 MHz -6 dBm measuring tone, 0.2 MHz measured difference tone
IP3 >= +32 dBm (2x -6 dBm measuring tone at 10 MHz
Maximum output voltage >= 1 Veff, 1 dB compression
Average noise level (without loops) <= -145 dBm/Hz (at 10 MHz)
Output impedance  
Max. Field strength  
Weight < 2 kg (incl. amplifier)
Height 690 mm (incl. Housing)
Amplifier dimensions 140 mm x 60 mm x 120 mm (without connectors)
Power requirements 6.0 V - 13.8 V, maximum +14.4 V
max. 80 mA
Environmental conditions: -20 - +40 grd C ambient temperature, <=100 % rel. humidity
IP65 (with connected loops and connection cable)
Compliance CE according to DIN EN 55013, EN 55020, EN 60065
RoHS / WEEE Directive, ear-Reg. 27676700
Amplifier Connectors RP-TNC for loops/node units
TNC for antenna feed
Control Unit  
Dimensions (W x H x D) 80 mm x 28 mm x 130 mm (without connectors / control elements)
Frequency range 10 kHz - 156 MHz
Power supply 9,0 - 15,0 V- / max. 250 mA
Connectors 2 x BNC 50 Ohm
2.5 mm x 5.5mm Hollow Pin
SMA female for WLAN
Maximum cable length from control unit to antenna max. 10 ohm DC resistance
Weight < 500 g
Environmental conditions: 0 - +40 grd C ambient temperature, <=90 % rel. humidity
IP65 (with connected loops and connection cable)
Compliance CE according to DIN EN 55013, EN 55020, EN 60065
RoHS / WEEE Directive, ear-Reg. 27676700
Control Antenna: Slow serial communication over anten cable
Remote control Windows App, WLAN

Reuter RLA4G

Can be a great help when working in difficult situations (PLC, computer noise, etc.). We use it every day for monitoring in densely populated areas.
Keith Rawlings wrote: Summed up in one word…Impressive!