Tagged: kerberossdr

KrakenSDR now in stock in our shop

As per our previous post we wanted to note that our direct sales KrakenSDR shop is now up and running with immediate shipping available. There is only a limited number of KrakenSDRs and antenna sets that we can sell direct to customers. After this stock is depleted all sales will need to go through Crowd Supply again. Regardless, both Crowd Supply and our direct sales shop are in stock right now.

If you weren't already aware, 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.  

KrakenSDR Shop now open
KrakenSDR Shop now open

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 www.krakenrf.com. 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 https://forum.krakenrf.com. 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.

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.

A Physical LED Vehicle HUD for KerberosSDR Radio Fox Hunting

Mark Jessop (@vk5qi) has recently been experimenting with a LED based hardware vehicle heads up display (HUD) that he has created to be used together with our KerberosSDR. The KerberosSDR combined with four antennas in a circular array determines the bearing towards a transmitter, and then the HUD displays this bearing visually on a circle.  

The HUD is cleverly designed so that the LEDs reflect on the windshield of the car, allowing for the lights to be safely seen on the windshield while driving. More videos of the HUD being developed and used can be seen on his Twitter feed.

In the video below Mark also shows how he combines KerberosSDR bearing data with his Chase Mapper software, which he uses for tracking down radiosonde weather balloons.

Mark's custom KerberosSDR HUD seen on Twitter

Mark writes:

For the last few months I've been piecing together a radio direction finding (also known as 'fox-hunting') system using a RTLSDR-Blog Kerberos-SDR, a custom-made antenna array, and my 'ChaseMapper' software. I have also recently added a 'heads up display' (HUD) box which displays the direction-of-arrival and SNR data from the Kerberos-SDR software.

I hope to put together a longer video showing how the system goes together sometime in the future, but this short clip shows how the system is used in the final approach to a radio transmitter (in this case, a 144 MHz transmitter from one of the Amateur Radio Experimenters Group organised night fox-hunts).

The antenna array consists of two 4-element nested arrays, one with 200mm antenna spacing for the 70cm band, and another with 425mm antenna spacing for the 2m band. The array is mounted to my car roof-racks, with phase-matched coax entering the car through a window-mounted bulkhead.

The red lines on the map indicate a bearing line produced by the Kerberos-SDR software. As we drive around the fox location, bearings are plotted, and we look for where they cross. There are always some inaccurate bearings due to multi-path issues, and misalignment between bearing acquisition time and the position/heading of the car, but it works well enough to be able to allow navigation to the transmitter location. The display can get fairly busy, so there are options to threshold by signal quality, and to 'age out' bearings over time.

The beeping noise you hear in the video is the signal from the radio transmitter, in this case a 144.390 MHz beacon which transmits short CW 'pips'. We were listening to the signal with an Icom IC-705 attached to an omnidirectional antenna so we knew when the transmitter started and stopped (and hence when to trust any bearings produced by the DoA system).

Towards the end of the video you can see the HUD in action, with the blue lights showing the estimated signal arrival direction, relative to the front of the car. As I slowly drive past the transmitter location (which I could see out the side of the car), the bearings swing to the right, and the SNR shows as being very strong. This is exactly what the display was intended for - it's not about getting hyper-accurate bearings, but more knowing when you need to turn left/right, or get out of the car!

Thanks to Will Anthony for capturing the video while I was driving!

Software used:

AREG Fox-hunt Activities: https://www.areg.org.au/archives/category/activities/fox-hunting

Finding a Radio Fox using a Kerberos-SDR + ChaseMapper

KerberosSDR is our 4-channel phase coherent capable RTL-SDR unit that we previously crowdfunded back in 2018. With a 4-channel phase coherent RTL-SDR interesting applications like radio direction finding (RDF), passive radar and beam forming become possible. It can also be used as four separate RTL-SDRs for multichannel monitoring.

KerberosSDR is soon to be replaced with the upgraded KrakenSDR, which will begin crowd funding on Crowd Supply later this year. Be sure to sign up on the Crowd Supply page to be updated once the campaign releases as due to long supply chain crisis related lead times, only a limited amount of stock will be initially available.

A KerberosSDR Based Radio Direction Finding RC Boat

If you weren't already aware KerberosSDR is our 4-channel phase coherent capable RTL-SDR unit that we previously crowdfunded back in 2018. With a 4-channel phase coherent RTL-SDR interesting applications like radio direction finding (RDF), passive radar and beam forming become possible. It can also be used as four separate RTL-SDRs for multichannel monitoring.

KerberosSDR is soon to be replaced with the upgraded KrakenSDR, which will begin crowd funding on Crowd Supply later this year. Please note that we have had some pandemic related delays finalizing the design, but progress is being made.

Recently we came across a brief demonstration video on YouTube where it appears that students have embedded a KerberosSDR into an RC boat. The boat carries four direction finding antennas connected to the KerberosSDR and autonomously navigates towards a signal source.

KerberosSDR Direction Finding RC Boat
Kerberos SDR project result

KerberosSDR direction finding #2

Unleash the Kraken(SDR): 5-Channel Coherent Capable RTL-SDR Coming Soon (Direction Finding, Passive Radar)

Back at the end of 2018 we successfully crowdfunded KerberosSDR on Indiegogo which was our first coherent capable RTL-SDR that consisted of four RTL-SDRs on a common clock, with built in noise source and phase synchronization hardware. KerberosSDR enabled interesting experiments such as radio direction finding and passive radar to be implemented at a much lower cost.

KerberosSDR has taught us many things, and we're now working on the next iteration which will be a significantly refined version known as "KrakenSDR". KrakenSDR will be a five channel common clocked RTL-SDR, with built in noise source and automatic phase synchronization hardware.

KrakenSDR will be crowdfunded on CrowdSupply, and we currently have a pre-launch page active at crowdsupply.com/krakenrf/krakensdr

Please sign up to the CrowdSupply KrakenSDR email list on the CrowdSupply page to be notified once crowdfunding is launched so that you will be sure to catch the early bird pricing discounts. We expect to be able to launch sometime within the next two months.

KrakenSDR Prototype with 5-Magnetic Whip Antennas

Unlike KerberosSDR, KrakenSDR has built in switching hardware that when combined with the new software, will automatically achieve sample and phase calibration without needing to manually disconnect the antennas each time the unit is powered up, or each time the frequency is changed. This allows for much easier mobile and remote use scenarios.

The addition of the fifth tuner also allows us to use a five element antenna array, which results in much improved direction finding accuracy and better multipath rejection. USB-C is also now used on both ports for greater port reliability, the PCB has been redesigned for lower noise, software controlled bias tees are present on each port, and it comes in a tough CNC milled enclosure that doubles as a heat sink.

Finally there is a new open source software base which uses the new synchronization hardware to perform auto phase calibration, allows for intermittent signals to be squelched and tracked, enables long term phase synchronization monitoring, and enables new possibilities for future code expansion especially for passive radar which we will be testing in the upcoming months.

Below are three videos demonstrating the KrakenSDR in action. Please subscribe to the KrakenSDR YouTube channel for more upcoming demonstrations.

KrakenSDR Radio Direction Finding Compass Test 1

KrakenSDR Radio Direction Finding Retune with Autocalibration Test 1

KrakenSDR Vehicle Radio Direction Finding Demonstrations

If you haven't seen them yet, it may also be interesting to watch our old KerberosSDR videos as well in the playlist below.

KerberosSDR Radio Direction Finding: Heatmap + Auto Navigation to Transmitter Location Demo 1

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

GPU Accelerated RTL-SDR Radio Interferometer Code For Radio Astronomy

Evan Mayer (@millijanskys) has recently released some code called “effex” that allows you to use two RTL-SDR dongles as an interferometer for radio astronomy and other experiments.

The hardware used is two RTL-SDR Blog V3 dongles with synchronized oscillators via the selectable clock headers, two 1420 MHz filtered LNAs, a splitter and noise source consisting of a 50 Ohm load and wideband LNA, and a NVIDIA Jetson Nano GPU single board computer. We note that Evans code should also run on our KerberosSDR with some modifications to enable the built in noise source during calibration.

To add to this Evan wrote to us explaining how this code might be used:

You could start to do some basic interferometric imaging by adding more coherent channels. This is exactly what Daniel Estévez just did with USRPs and GNU Radio at the Allen Telescope Array.

Did you see the “picture” of the supermassive black hole shadow released by the Event Horizon Telescope collaboration in 2019? The “ring of fire” or “donut” image? Daniel’s image and that image were created by “aperture synthesis.”

In aperture synthesis, the signals from each pair of antennas distributed across an area can be cross-correlated to measure one component of the 2D Fourier transform of the radio brightness distribution on the sky. But, you need coherent receivers (or REALLY good time stamps) to cross-correlate the signals from the antennas. Get enough pairs of antennas, and you can start to more fully sample the 2D Fourier space of the sky brightness distribution, which you can then use to reconstruct a real image.

This is how distributed radio arrays like the EHT work, as well as localized ones like ALMA or LOFAR.