A phase-coherent software defined radio with five RTL-SDRs

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Passive Radar & RF Transmitter Localization

A coherent radio allows for very interesting applications, such as radio direction finding, passive radar, and beamforming. You might be interested in KrakenSDR if you are a ham radio operator participating in a fox hunt or monitoring repeater abuse, a professional RF engineer tracking down sources of noise and illegal broadcasts, an instructor demonstrating RF fundamentals, an amateur radio astronomer looking to increase image resolution, a search and rescue team locating a disaster victim, an owner of a very large property monitoring its use, or a conservation group tracking tagged animals outside of network coverage.

KrakenSDR is KerberosSDR++

The previous version of KrakenSDR was known as KerberosSDR, which we successfully crowdfunded on Indiegogo. All backers of KerberosSDR received their orders and the relevant source code for direction finding and passive radar. KrakenSDR improves upon KerberosSDR in several important respects:

  • Automatic calibration hardware. There is no more need to manually calibrate and disconnect antennas during calibration. It all happens automatically when you change frequency. This will allow for KrakenSDR stations to be remotely operated.
  • Five channels. KrakenSDR has five channels instead of four, which greatly improves direction finding accuracy.
  • Low-noise design. KrakenSDR has a cleaner spectrum with much less internal noise than KerberosSDR.
  • USB Type-C ports and rugged, CNC-milled enclosure. KrakenSDR is built for high reliability in the field.
  • Interface with external devices. Bias tees on all ports allow for LNAs and other devices to be powered easily.
  • Improved software. Built on the foundation of the KerberosSDR software, the KrakenSDR software adds autocalibration and tracking of intermittent signals.

Features & Specifications

  • Five-channel coherent-capable RTL-SDR
  • Built-in coherence synchronization hardware
  • Automatic coherence synchronization via provided Linux software
  • 24 MHz to 1766 MHz tuning Range (standard R820T2 RTL-SDR range)
  • 4.5 V bias tee on each port
  • Core DSP software is open source and is designed to run on a Raspberry Pi 4 (see links below)
  • Direction finding Android software (free for non-commercial use)
  • Custom antennas set and programmable test beacon also available

Support & Documentation


KrakenSDR Radio Direction Finding Compass

KrakenSDR Radio Direction Finding Retune with Autocalibration

KrakenSDR Vehicle Radio Direction Finding Demonstrations

KrakenSDR Passive Radar

KerberosSDR Tracking a Weather Balloon

KerberosSDR Monitoring Air Traffic Control with an RPi 3 B+

Passive Radar Peak Hold

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