1、DIRECT SAMPLING MODE: RTL SDR receiver to use the direct sampling mode, first connect the appropriate HF antenna to the SMA antenna port. In SDR, select the Q branch in the configuration menu. Press Play and tune to 500 kHz‑28.8 MHz. 2、BIAS TEE: The V3 RTL SDR introduces a bias tee that can be easily enabled in software. Some customers have been building devices that require multiple RTL SDR dongles and these isolation holes should help with stacking. 3、PROFESSIONAL DESIGN: For advanced users who need to chain clocks together for coherent experiments, or need access to other ports. You can bridge the clock selector directly with a solder bridge, or solder on a 1.27mm/0.05in 2×2 header pin jumper. 4、STANDARD MATCHING CIRCUIT: The standard matching circuit on the RTL SDR is designed for use with DVB T and tends to attenuate signals above 1 GHz. The new matching circuit has less attenuation above 1 GHz and similar performance below. 5、PERFECT FOR YOU: SMA software defined radio receiver allows you to listen to high frequency signals between approximately 500 kHz and 28.8 MHz. Suitable for many applications to meet your different usage needs. Item Type: Software Defined Radio Receiver Material: Aluminum Alloy Bandwidth: Up To 2.4 MHz, Stable ADC: RTL2832U 8 Bit Frequency Range: 500 KHz-1766 MHz (500 KHz-24 MHz In Direct Sampling Mode) Typical Input Impedance: 50 Ohms Typical Current Output: 270-280 MA 1 x Software Defined Radio Receiver