1. COMPLETE CIRCUITS: Such as anti battery reverse connection, over discharge, over , over current, and short circuit are built into the active loop broadband receiving antenna.2. FINE WORKMANSHIP: The shell is CNC processed, with high frequency PCB design and high density copper 50‑1.5 feed line, using premium materials to create a highly antenna with excellent performance.3. WIDE WORK RANGE: No external power supply is needed. It works in a frequency range from 50kHz to 500MHz, covering long , medium , short , FM broadcasting frequency range, and VHF aviation frequency range.4. HIGH GAIN: The gain flatness within the working bandwidth is very good. It provides approximately 17dB gain and still has about 7dB gain even when working at 450MHz.5. IMPROVED PERFORMANCE: The amplification board in the small loop antenna adopts an improved version of the LZ1AQ low noise amplifier, with a bandwidth from 50kHz to 500MHz and a gain greater than 10dB. It has a low input impedance (1.2Ω at 1MHz) to effectively reduce electric field interference. It is powered by a 12V linear power supply with a current not exceeding 150mA.6. WIDE APPLICATION: The diameter of the high frequency radio antenna is 60cm, which can be installed outdoors, on balconies, and on rooftops without occupying too much space. The preamplifier box is completely waterproof. It is the best short radio antenna for those who cannot hanging long wires high in a quiet rural environment.Specification:Item Type: Active Loop AntennaMaterial: Aluminum Alloy, CopperReceiving Frequency Range: 50kHz to 500MHzGain: 17dB at 10MHzOutput Noise: -125dBm(at 10MHz, BW=100Hz)P1dB: +15.5dBm at 10MHzOIP3: +38dBm at 10MHzPower Supply Voltage: 9V to 12VPower Supply Current: 130mA to 150mAAntenna Interface: SMA(M)Output Interface: SMA(F)Small Ring Coaxial Cable Model: Rg402Small Ring Coaxial Cable Loss: 0.145db/MSmall Loop Antenna Diameter: