This is an RTL SDR blog software defined radio receiver with RTL2832U ADC chip, R828D tuner, 1PPM TCXO, SMA F connector and aluminium case with passive cooling. Tunes from 500 kHz to 1.7 GHz with up to 3.2 MHz (2.4 MHz stable) of bandwidth. Perfect for use as a computer based radio scanner with free software like for SDR#, for HDSDR, for SDR-Radio, for GQRX or for SDR Touch on for Android. Works on Windows, OSX, Linux, Android and Computers like The for Raspberry Pi. Great for many applications including general radio scanning, air traffic control, public safety, for ADS-B aircraft radar, for marine AIS, for ACARS, for trunked radio, for P25/MotoTRBO digital voice, for POCSAG, for weather balloons, for APRS, for NOAA APT/ Meteor M2 weather satellites, radio astronomy, DAB, or as a low cost panadapter with a ham radio. This model has several improvements over other brands. It uses the improved R828D tuner, has an improved front end with filtering, a 1PPM TCXO, better components, a redesigned lower noise PCB, cooling improvements, extra ESD protection and an SMA F connector. It also has a software activatable bias-tee for powering LNA's and active antennas. It also has HF reception capabilities. Most standard RTL-SDR dongles can tune down to 24 MHz at the lowest. This model has a built in upconverter, and allows for tuning down to 500 kHz. There is a built in 28.8 MHz low pass filter for optimizing this mode. Please note, this is the V4 unit and not all software is compatible with it yet! Compatibility with most programs on Windows and Linux is now OK, but for MacOS and for Android is still catching up. Colour:Photo Color Material:plastic Package Contents: 2 x Radio Receiver