Check the listing for details. High Resistance Amplifier Donut Antenna Mini Loop Antenna For SDR Radio Receiver. Condition: New. Listed at 21.99 USD. Features:Enhances your radio reception with the 300MHz DonutAM MW/SW Mini Loop Antenna Replacement.The highimpedance amplifier is designed to convert high impedance into a standard 50ohm output, ensuring impedancematching and isolation. Suitable for various antenna likedonut whip antenna, and magnetic rod antenna, it greatly improves reception performances.for radio enthusiasts, broadcast professionals, and wireless communication enthusiasts, the high impedance amplifier is a must have accessory for any radio receiver, or walkietalkie.The high impedance amplifier provides reliable signal amplification for passive antenna reception. Perfect for use with donutantenna, magnetic rod antenna, and more.Experience clear audioand improved signal strength with the high impedance amplifier. your radio reception and enjoy a wide frequencies with this compact and durable aluminum alloy device. Specifications:Input : 1MΩOutput: 50ΩBandwidth: 300MHzCharging:5VInternal battery capacity: 600mAHCharging current: 800mAWorking hours: more than 24hours Package Includes:Package 11PC High Resistance AmplifierPackage 21PC High Resistance Amplifier1PC DonutSW Antenna1PC DonutMW Antenna