Category: KerberosSDR

KrakenSDR Field Reports and Software Updates

We've recently published an update about KrakenSDR field reports and software updates to our KrakenSDR CrowdSupply page. We are cross posting here as well. This update provides some demonstrations of the KrakenSDR that users have uploaded, and provides some updates on some new software that we have been working on.

Also as we'll note shortly in a separate post, we wanted to highlight that our website for direct sales of KrakenSDR and antenna sets is now live at our KrakenSDR shop. Please note that we only have a limited number of KrakenSDRs that we can sell directly, and once they run out, all other sales must go through CrowdSupply.

Field Reports

User YouTube Demonstrations

Frugal Radio

In this video Frugal Radio unboxes and tests his KrakenSDR and Krakentenna's on a vehicle. He is able to come to the location of two unknown transmitters within minutes.

KrakenSDR Unboxing / Prep & Setup device & antennas : Part 1

KrakenSDR - WOW! Amazing Direction Finding Tests : Part 2

F4IPO Demo

In this video F4IPO demonstrates his ability to use a KrakenSDR and Krakentennas to locate a TETRA transmitter within 5 minutes.

KrakenSDR : recherche d'un émetteur TETRA

DragonOS Kraken Pro Cloud Mapper Demo

In this video Aaron, creator of DragonOS demonstrates two networked KrakenSDR devices being used with DF-Aggregator and an alpha version of our Kraken Pro Cloud Mapping software (introduced further below). One KrakenSDR is fixed, and another is on a moving boat. He is able to track a beacon on land.

DragonOS Focal Direction Finding w/ KrakenSDR + Boat (Steam Deck, GS66, DF-Aggregator, Kraken Dash)

F1MIJ Demo

In these videos F1MIJ provides multiple screen recordings of the KrakenSDR Android App in action during a drive.



KrakenSDR sur la fréquence du relais de Valenciennes ( Vidéo N°2 )

Manuel Lausmann Unboxing Video

In this video Manuel Lausmann unboxes the KrakenSDR.

Ein Kraken aus Texas

Matt Blaze Twitter Thread

In this Twitter thread Matt Blaze @mattblaze describes his experience with the KrakenSDR and shows that he was able to determine the location of a 103.5 MHz transmitter. Matt notes that apart from some hardware limitations, his experience with the KrakenSDR is even better than with his extremely expensive high end R&S DDF007.

@cemaxecuter Twitter Demos

Aaron (whom we mentioned earlier) has also been heavily posting on Twitter showing how he's been successful at getting his KrakenSDR running on a SteamDeck, a new type of handheld gaming device from Valve.

He also briefly demonstrates the KrakenSDR being used as five independent receivers in SDRAngel.

Website Release

We also wanted to note that we now have our website live at This is mostly a marketing and general overview website. All the technical documentation and guides will remain on the GitHub Wiki.

KrakenSDR Forum

We have also now released our KrakenSDR forum at If you have general questions, or support inquires please post there rather than through email so everyone can learn. If there are specific software bugs, please continue to post those as GitHub issues.

Kraken Cloud Pro Alpha Release

We are now releasing an early alpha version of our online 'Kraken Cloud Pro' service. We want to note that this software is still in ALPHA status. That means that all the intended features are not yet implemented, and that it may have multiple bugs. We also do not guarantee any uptime for this service at this time.

Kraken Pro Cloud is our online cloud mapping solution for KrakenSDR devices. It allows you to upload KrakenSDR direction finding data onto our central server, so that you can combine bearing data from multiple geographically distributed KrakenSDR devices. With the right geography of the receivers and transmitter, this allows you to instantly determine the location of a transmitter without needing to take multiple readings with a vehicle.

Documentation on the use of Kraken Pro Cloud is available on our Wiki at this page.

You can also do offline analysis of log files collected from the Android App or recorded via the Web GUI.

Kraken Pro Cloud Timelapse Demo

As part of the testing of the service we recorded a timelapse of a KrakenSDR station tracking a weather balloon.

The above is a video of a simple timelapse demo of the system tracking a weather balloon from a single station. Because it's only a single station, the red estimation dot can be ignored. The yellow dot indicates the actual GPS location of the weather balloon. Once the weather improves we'll be setting up a distributed two-station test.

One interesting thing to note is how the KrakenSDR tracks the balloon accurately, until the elevation angle between the antenna and balloon goes above 45 degrees which happens when the balloon rises higher and comes too close to the station. At this angle the antenna array can no longer track the balloon correctly. Once the balloon falls to a lower altitude and the elevation from the antenna is less than 45 degrees accurate tracking resumes.

In the near future we will be uploading more demonstrations like this with multiple stations set up.

Quick Demo of our KrakenSDR Network Mapping Direction Finding Software (Alpha)

The KrakenSDR is our 5-channel coherent radio based on RTL-SDRs, and it can be used for applications like radio direction finding and passive radar. We successfully crowd funded the device on Crowd Supply back in November 2021.

Over the past year we've been working on a networked mapping system for KrakenSDRs that will allow distributed units to contribute radio direction finding bearing data to a central server. This allows for multiple fixed KrakenSDR sites to combine live bearings, allowing for near instantaneous localization of transmission sources.

We are close to releasing an alpha version of this software for KrakenSDR and KerberosSDR customers to test, and will have news about signups within the next few weeks. For now it will be restricted to three networked units per user.

In the future we plan to add (reasonably priced) advanced features like support for more units, history rewind, multi-channel layering, remote KrakenSDR management, object tracking, ID differentiation, and recording and playback of mp3 sound bites based on tracked location. 

Below is a simple timelapse demo of the system tracking a weather balloon from a single station. Because it's only a single station, the red estimation dot can be ignored. The yellow dot indicates the actual GPS location of the weather balloon. Once the weather improves we'll be setting up a distributed two-station test.

One interesting thing to note is how the KrakenSDR tracks the balloon accurately, until the elevation angle between the antenna and balloon goes above 45 degrees which happens when the balloon rises higher and comes too close to the station. At this angle the antenna array can no longer track the balloon correctly. Once the balloon falls to a lower altitude and the elevation from the antenna is less than 45 degrees accurate tracking resumes.

KrakenSDR now Shipped to the Majority of Crowd Supply Backers

If you weren't aware of it, KrakenSDR is our RTL-SDR spinoff project and is a 5-channel coherent RTL-SDR that we have successfully crowdfunded for over on Crowd Supply. KrakenSDR is the successor to our previous 4-channel coherent product called the KerberosSDR. With a radio like KrakenSDR that is capable of coherence between channels, interesting applications like direction finding and passive radar become possible. You can also use it as five independent RTL-SDRs should you chose to.

We wanted to note that all units preordered through the Crowd Supply crowd funding campaign are now at the Crowd Supply / Mouser warehouse, and the majority have already been shipped out to customers!

The KrakenSDR with 5x Krakentenna's
The KrakenSDR with 5x Krakentenna's for Radio Direction Finding

Additional units for new purchasers are in a mixture of production and freighting and will be available for fulfillment as soon as we can. We are constrained by supply and production time, so if you're interested in a KrakenSDR, please get your order in so that you have an earlier place in the queue.

KrakenSDR Production
KrakenSDR Boxes

Other Recent KrakenSDR Updates

Wiki Manual: Our Wiki manual and guide is up at It covers topics from what you need to get started, radio direction finding theory and background, antenna array setup, KrakenSDR Web-GUI software guide, Android App guide and a Passive Radar guide. 

GNU Radio: We have recently released a beta version of a KrakenSDR GNU Radio block and examples at

GNU Radio KrakenSDR DOA Flowgraph

Install Scripts, VirtualBox Images, Docker: For general vehicle based direction finding, which is the most popular application, we recommend using our premade Raspberry Pi 4 image for easy almost plug and play setup. But to ease installation on other computing devices (especially as the Pi 4 stock is non-existent at the moment due to the supply chain crisis) we've now created an automatic Linux install script and a Virtual Box image which can be run on Windows or Linux host machines. Third parties have also released a Docker container. See this page on our Wiki for more information.

Customer Feedback: We've also had some great customer feedback so far with one user submitting examples of his success in locating transmitters like a 162 MHz NOAA weather station, and various fox hunt beacons. 

KrakenSDR Direction Finding with Android App

Arrow Antennas: For fixed site direction finding installs, Arrow Antennas is now shipping their 5-element dipole antenna array.

If you're interested in the latest KrakenSDR updates, please follow us on the Crowd Supply mailing list, and keep an eye out for our official website releasing soon.

SI-SDR-UG Recorded Livestream: Corey Explains DF-Aggregator for KrakenSDR and KerberosSDR

The South Indian SDR User Group (SI-SDR-UG) have recently held their fourth live stream conference. This conference included some interesting talks such as:

  • "Introduction to GNU Radio Series, Part 2" by Neel Pandeya
  • "Silice, a Language for Hardcoding Algorithms into FPGA Hardware" by Dr.Sylvain Lefebvre
  • "RF Geo-Location for Everyone" by Corey Koval
  • "Overview of Wireless Channels, Part 1" by Aditya Arun Kumar

In particular we were interested in Corey's talk which starts at 1:27:40 and talks about DF-Aggregator, an open source mapping program he's written for KerberosSDR, KrakenSDR and any other radio direction finding hardware that can be adapted to the software. In the talk Corey explains what DF-Aggregator is and how the clustering algorithm works.

South Indian SDR User Group (SI-SDR-UG) Live Stream Event-4

Using the New KrakenSDR Software with DF-Aggregator and a KerberosSDR

KrakenSDR is our 5-channel coherent RTL-SDR product that we have successfully crowdfunded for over on CrowdSupply. KrakenSDR is the successor to our previous 4-channel product called the KerberosSDR and will begin shipping to initial supporters within the next few months. Along with the new hardware developments, KrakenSDR comes with a new opensource codebase that is also compatible with the KerberosSDR. 

With a coherent SDR like KrakenSDR or KerberosSDR, interesting applications such as radio direction finding and passive radar become possible.

Unlike the newer KrakenSDR, the KerberosSDR is unable to automatically calibrate without manual intervention on the hardware. However, it is possible to upgrade the KerberosSDR with some third party hardware switches provided by Corey Koval of Lakeshore Labs. With these switches and the new software the KerberosSDR can be made to automatically calibrate like the KrakenSDR.

Corey also has created DF-Aggregator, which is open source software that allows users to plot bearing data from one or more KerberosSDR, KrakenSDR or other radio direction finding devices on a map.

Recently, Corey has demonstrated some changes to our codebase that allow the new KrakenSDR software to directly upload to DF-Aggregator. Over on his YouTube channel, Aaron who runs the DragonOS channel has uploaded a video that shows exactly how to set this up. In the future we plan on integrating support for DF-Aggregator directly into our core code.

DragonOS Focal KrakenSDR Software Setup and Connection w/ DF-Aggregator (KerberosSDR, Pi4)

KrakenSDR Crowd Funding Campaign Ends Fully Funded

Thank you to everyone who has backed or been following our KrakenSDR project on Crowd Supply. The initial funding campaign has now concluded with almost 5x our minimum funding goal! If you missed out, please don't worry as the product is will still be available for sale on Crowd Supply at the campaign price, but later orders may receive units from the second batch produced a few months after the first.

Thanks to the successful funding campaign we now have all the required parts on order and we expect the factory to receive them in a few weeks time. The final confirmation prototype is in production now, finishing touches to the enclosure are being worked on, a QC process is being developed and EU compliance certification and logistics details are being worked through.

At the same time work on on the DFing software is continuing to progress as well. If you are testing the software with the older KerberosSDR units, please note that the software is still in beta and that a thorough reading of the documentation is required to understand the DAQ control parameters. As direction finding with an SDR can involve learning a lot of new technical information, we are aiming to significantly simply the knowledge that is needed to understand the DAQ parameters, and hope to have a simplified version released with a tutorial by mid-December. So if you have a Kerberos, and are struggling with the setup, please kindly wait until the official release, unless you are interested in learning the nitty gritty technical details.

Recently we have also been working on improvements to the intermittent signal squelch handling and we are also working on multichannel DFing capabilities. We have a new developer starting work on a multiplatform networked mapping program too.

We are also looking to sponsor some accelerator projects such an GNU Radio integration and beam forming investigations for applications like radio astronomy. If you have DSP programming skills, and you're interested in helping on this, or have the DSP skills and interest in developing another project, please email us at [email protected] with details.

The KrakenSDR
KrakenSDR Latest Prototype Enclosure

KrakenSDR CrowdFunding Week 1 Updates

The following was posted to our Crowd Supply page as an update to our KrakenSDR crowd funding project.


Thanks to everyone’s amazing support we were able to fund in less than 24 hours from release! Now, thanks to funding, we can move on to the job of finalizing our batch manufacturing and accelerating development of our codebase.

Please keep in mind we’ve sold almost half of the first batch of 1000 units! So, if you have been hesitating, please get your order in soon since subsequent batches could be susceptible to manufacturing delays.

Enclosure Update

The design of the KrakenSDR enclosure is coming along nicely and we expect to be cutting the new prototype soon. The image below shows a 3D rendering (the blank space in the middle will contain the logo). The enclosure is a critical part of the KrakenSDR as it helps add thermal mass and cooling ability. Phase drift can occur when the tuner chips experience temperature fluctuations, so adding thermal mass helps to dampen ambient temperature changes significantly. The PCB is thermally connected to the enclosure via a thermal pad. The enclosure, of course, also helps block signals from directly entering via the PCB, which could skew results.

Arrow Antennas Update

Unfortunately Arrow Antennas have recently informed us that delivery of their five-element, fixed-site, dipole array we mentioned in the campaign text is going to be delayed due to the aluminum shortage crisis in the USA. We’re holding out hope this will be resolved early next year by the time we ship. Please note that this has no impact on the $99 set of five magnetic mount antennas offered directly by us through the campaign.

Support for KerberosSDR

There have been some concerns that the release of KrakenSDR means support for new developments on our previous product KerberosSDR is abandoned. We have stopped development on the older KerberosSDR code, but we want to clarify that KerberosSDR is fully supported by our new KrakenSDR code, which is a massive improvement.

The new code is designed to be compatible with x-channel Kerberos/Kraken style receivers. So it can support the four-channel KerberosSDR and the five-channel KrakenSDR as well as any DIY system with x-channels. The only change required will be setting the RX channel count in the configuration. The main disadvantage with the older KerberosSDR hardware is that even with the new code, you still will need to manually disconnect the antennas when calibrating (e.g., at startup or frequency retune).

If you have a KerberosSDR, you can try this code out right now by cloning and installing heimdall_daq_rx and krakensdr_doa. Everything, including install instructions and documentation, is in the development branches of our GitHub repo (please note this setup may be a little involved at the moment as the code is evolving rapidly). When the code is fully released, the ready-to-use Pi4 SD card will be usable with KerberosSDR simply by changing the RX channel count.

We have also considered the Android App and are happy to announce that all our previous KerberosSDR customers will receive a license for the upgraded app when it is released too. KerberosSDR customers, please keep an eye on the email address you used with your order for updates on that in early 2022.

Testing & Development

This week, the 4.5V bias tees were put through a stress test by powering five wide-band LNAs. This is working beautifully with a 5V, 3A power supply. A 3A supply will be required if you are intending to power an LNA on each port, as the KrakenSDR itself draws 2.2A maximum load when all tuners and the noise source is active.

We have also been testing how the KrakenSDR could be coupled with a small, low power, 10dBm 433 MHz ISM band CW beacon based on the Heltec WiFi Lora 32 hardware, but modified to run the LoRaFox fox hunting beacon software. The range of this low power beacon at 10dBm seems to be roughly three kilometers/two miles with the beacon obscured inside the glovebox of a car. We plan to provide more info on these tests in the next few weekly updates as we think there is an application for similar low power beacons combined with KrakenSDR for local asset, pet, or wildlife tracking.

We are also beginning work on our network mapping solution, which will allow users to run multiple KrakenSDRs in an area with all units uploading data to a central server over the internet. The server will run a web-based version of our Android app, collecting and plotting all bearing data on the same map, and determining a likely TX position. We hope to have a working beta out by the time we ship early next year.

Release the KrakenSDR! CrowdFunding now on Crowd Supply

KrakenSDR is now available for crowdfunding on Crowd Supply. Thank you to all interested parties for your patience while we navigated recent pandemic-related delays.

KrakenSDR is a five-channel, RX-only software-defined radio (SDR) based on the RTL-SDR and designed for phase-coherent applications and experiments. Phase-coherent SDR opens the door to some very interesting applications, including radio direction finding, passive radar, and beam forming. You can also use KrakenSDR as five separate radios.

KrakenSDR is an upgraded version of our previous product, KerberosSDR. It provides a fifth receive channel, automatic phase-coherence synchronization capabilities, bias tees, a new RF design with cleaner spectrum, USB Type-C connectors, a heavy-duty enclosure, upgraded open source DAQ and DSP software, and an upgraded Android app for direction finding. We are constantly working on new software and sample applications, so keep an eye out for future updates!

We expect to ship the first 1000 KrakenSDR units to backers before the end of March, 2022. And by the time that happens, we’ll have published a full range of in-depth tutorials to help you get started.

KrakenSDR Promotional Video

Some of our previous KerberosSDR and KrakenSDR posts might also be of interest.