Feature:1. COMPLETE PROTECTION CIRCUITS: Such as anti battery reverse connection, over discharge, over charge, over current, and short circuit protection 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 501.5 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 wave, medium wave, short wave, 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 (1.2 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 wave 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: Approx. 60cm / 23.6inAbout: Small loop antenna (hfdloop) is a small size full band ring magnetic field active receiving antenna, receiving frequency range 50kHz to 500MHz, mainly by the top jumper board, small loop amplifier board, small loop coil, feeder, feeder and 12V linear power supply, in which the top jumper board and small loop amplifier board there are several groups of switches. Small loop antennas of different structures can be realized by adjusting the position of the switch, in which for Mobius loop can achieve twice the voltage gain of ordinary small loop; The electric field shielding ring can effectively reduce the interference caused by the surrounding electric field, such as lightning, electrostatic discharge, etc. The structure of the unshielded ring is simple, the small ring as a whole can be replaced by a thicker wire, the size is simple to modify, and it is easy to set up..Package List:1 x Loop Antenna Amplifier1 x Headphone Jack Adapter1 x Top Jumper Board2 x Small Loop Coils (RG402 Coaxial Cable)1 x 7m Feeder Cable1 x 1m Feeder Cable2 x Adhesive Hooks1 x EVA Storage Bag1 x Power Supply