Over on YouTube Thomas Brinkoetter has uploaded a video demonstrating his experience with the KrakenSDR, and how he used it to find an intermittent interferer that he set up for a test. The video was prepared to support the RF Interference and Mitigation class at the IWCE trade show Las Vegas March 17 and 18th 2025.
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. It can currently be purchased either directly from our krakenrf.com website, or from Crowd Supply or Mouser.
The test involved his wife keying up a repeater for one second out of every 15 seconds. In the video Thomas was able to successfully locate the transmitter with an antenna array and KrakenSDR mounted in his vehicle.
Locating an intermittent interferrer with the Kraken SDR
Over on his YouTube channel, sn0ren has uploaded a video showing his experience with the KrakenSDR. 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. It can currently be purchased from Crowd Supply or Mouser.
In the video, sn0ren explains radio direction finding in general and then goes on to show how to set up and use KrakenSDR. Sn0ren writes:
Wireless communication is inherently anonymous. There is no way of knowing who transmitted a signal if they do not identify. And there is no way of knowing where that signal is transmitted from. Unless you actively track it down. KrakenSDR is a radio direction finding device that uses an array of antennas and synchronised receivers to track down the position of a given radio transmission and lead you directly to its physical location.
Over on YouTube The Comms Channel has uploaded a video showing how they used a KrakenSDR to track down the location of an ATIS transmission tower.
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. It can be purchased on Crowd Supply.
Airports typically have an ATIS (Automatic Terminal Information Service) transmission tower that broadcasts audio of recorded information such as weather, runway conditions, and any important notices.
In the video, they use the KrakenSDR to track down the location of an ATIS transmission tower at their local airport. In the future, they intend on using the KrakenSDR to help track down Meshtastic radios.
Radio Direction Finding with the KrakenSDR | Radio Direction Finding Series
This post is about the KrakenSDR, one of our products from our sister company KrakenRF. 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. It can be purchased on Crowd Supply.
In this update we'd like to share some of the KrakenSDR projects we've been working on, as well as various projects we've seen from our customers.
Kraken Pro Cloud Online Mapper Updates
Recently we've been working hard at improving the 'Kraken Pro Cloud' online mapper service at map.krakenrf.com. If you were unaware, this service is an online mapping application that can be used together with one or more KrakenSDRs to display their generated bearings on a map. This is useful if you have multiple KrakenSDRs at fixed sites spread out over a wide area, as it allows you to instantly triangulate. The features include:
Multiple Kraken's displaying on a single map
Display a Heatmap just like the Android App
Ability to remote control the Kraken's individually, or all together from a single interface
Ability to share your Kraken with other users
Display log files collected from the Android App or Kraken Web GUI
Recently we've added multiple new features and improved several points:
Ability to plot multi-VFO (multi frequency) data coming from a KrakenSDR
Ability to put Kraken's into groups
Improved heatmap calculation and rendering speed
Fixed a memory leak that caused the mapper to crash after several hours
Improved the history feature (see further below)
Improved the interface
We'd like to especially highlight the improvements to the history feature. The history feature allows you to look back in time and see what the bearings and heatmap at that time looked like. This is useful if you are tracking something, but don't know exactly when the transmissions occur, or are tracking a moving object, and want to be able to review data at a later time.
Currently, we are supporting up to a week of free history, but this may change depending on how much history affects server load. For full disclosure, we eventually plan on making longer history recording available, but this will likely be a paid subscription feature. The timeframe of free history provided may change in the future too.
We also added the ability to play back history at faster speeds, kind of like a timelapse. To do this the heatmaps for each interval need to be precomputed first so that the playback is smooth, and so a 'precompute' button has been added.
We also want to note again that Kraken Pro Cloud is currently in beta, and there may still be some bugs. We also do not guarantee any uptime or privacy so please do not use the service for mission critical tasks. If you encounter bugs, please report them on our forums at https://forum.krakenrf.com, or via email to [email protected].
The gif animation below shows heatmap playback at 4x speed while the KrakenSDR was tracking the bearing towards a weather balloon.
Kraken Pro Cloud Mapper History Playback
KrakenSDR Core Updates
Since the last update we have made various bug fixes and a few minor changes to the core software. We highlight some changes below:
Our images have been updated to include SignalMedic's TAK server. (More on this in a section below)
(Beta feature) Added the ability to demodulate narrowband FM to audio files. This is in beta as the audio files don't come out particularly clean sounding, but it may be useful for some.
With the release of the Raspberry Pi 5, we have now also added a Raspberry Pi 5 ready-to-use image as well. The Raspberry Pi 5 runs the KrakenSDR software very smoothly and makes the GUI very responsive. Performance is similar to the Orange Pi 5. If are are new and choosing a platform to run the KrakenSDR on, we would highly recommend the Raspberry Pi 5 now.
Recently we have been working on getting an iOS version of the KrakenSDR app out. The app is close to completing development and should be out within about a month. Once released we will update our Wiki with links to the app, or you can simply search on the iOS app store for 'KrakenSDR'
KrakenSDR Crowdsupply Conference Workshop
One of the members of our team, Syed, recently ran a workshop on KrakenSDR. The workshop had attendees put together a KrakenSDR set on a large pizza pan and had teams go out into a local park to find a hand held radio transmitter. Photos of the day can be found here.
KrakenSDR Workshop at the Crowd Supply Conference
Highlights from Customers
KrakenSDR YouTube Tutorial from Skyler F
Over on YouTube user 'Skyler F' has uploaded a great video that demonstrates and shows how to set up KrakenSDR. In the video he demonstrates him finding some cellular phone towers.
Kraken Radio Direction Finding Unit Setup Tutorial and Demo
KrakenSDR Talk by KO4CEQ
We've also seen a great talk by KO4CEQ about KrakenSDR which has been uploaded to YouTube. In the talk he discusses KrakenSDR and shows his very neat car based setup.
PCARS March 2024 Mobile DF with KrakenSDR
Elektor Review of the KrakenSDR
Online store and magazine Elektor has uploaded to their blog a great review of the KrakenSDR. In the review they explain the KrakenSDR specs, and how it can be used as a regular SDR, and then go out to show how they created an antenna array and used the DoA software.
Elektor's Review of the KrakenSDR
Signal Medi's TAK Server
Thanks to 'SignalMedic' who had coded up a TAK server for KrakenSDR. TAK (Tactical Assault Kit) is software used by the military and other organizations for visualizing geospatial information such as enemy and friendly positions. Civilian versions of TAK also exist, such as ATAK for Android.
The TAK server allows for a KrakenSDR cursor to appear on a TAK map. TAK only allows for a single bearing line to show, so it's not as effective as our own mapping app, but this may be useful for customers who are only using TAK.
SignalMedic has made two implementations. One based on NodeRED, and the other based on Python. As mentioned previously, our image files now include the Python TAK server.
KrakenSDR TAK Server by SignalMedic
Aaron (aka cemaxcuter, aka creator of DragonOS) has also uploaded a video showing the TAK server in action.
WarDragon KrakenSDR to TAK Server w/ Node-RED (KrakenSDR)
Adrian's 3D Printed Antenna Spacer Arm
In the past we've highlighted Adrian's excellent 3D printed antenna spacer. The files for the 3D printed antenna spacer are available on Thingiverse.
Adrian has recently created a modified version of the arm that is significantly longer and should be able to cover 150 MHz to 1766 MHz. He also notes that he's updated the original arm to include files for laser cutting.
Dbvanhorn 3D Printed Antenna Spacer
We've also seen another 3D printed antenna spacer uploaded to Thingiverse. This file is based on OpenSCAD and allows you to customize the length to be printed.
Over on YouTube user Skyler F has posted a video showing him unboxing his KrakenSDR, and KrakenSDR antenna set, and then setting it up and taking it on a test to find the location of a cellular tower. In the video Skyler shows how to set up the antenna array using the paper spacers, how to connect the KrakenSDR to a Raspberry Pi, and how to configure the Android direction finding app.
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. It can be purchased on Crowd Supply.
Kraken Radio Direction Finding Unit Setup Tutorial and Demo
Over on YouTube Aaron, creator of DragonOS and the WarDragon portable SDR kit has posted a video showing how he was able to set up an run the KrakenSDR to TAK python software, as well as a Federate TAK server on WarDragon. Aaron writes:
In this video, we delve into the integration between the KrakenSDR and TAK (Tactical Assault Kit) server, orchestrated by SignalMedic. SignalMedic introduces his Python-based update to his previous NodeRed-dependent system, designed to extract data from the KrakenSDR and relay it to a TAK server.
Witness the capabilities of SignalMedic's creation as we showcase its functionalities with two KrakenSDR endpoints, transmitting lines of bearing and other information to our TAK server setup. We explore setting up and running SignalMedic's project on a WarDragon, a custom kit powered by DragonOS that I've enhanced with a KrakenSDR specifically for this demonstration.
Join us as we demonstrate the integration between the KrakenSDR and the TAK server, showcasing the ease of setup and operation, thanks to previous tutorials on setting up a TAK server and configuring inputs for KrakenSDR data streams. We address challenges encountered during communication between TAK servers and discuss the manual certificate import process from SignalMedic's server to ensure smooth operation.
Additionally, we touch upon federating two TAK servers to enable seamless information sharing between environments, enhancing situational awareness and operational efficiency.
I also mention the perviously explored the Goatak project, an ATAK client for Linux written in GO, which promises to expand the capabilities and accessibility of TAK operations on Linux platforms.
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. It can be purchased on Crowd Supply.
TAK (Tactical Assault Kit) is software used by the military and other organizations for visualizing geospatial information such as enemy and friendly positions. Civilian versions of TAK also exist, such as ATAK for Android. Previously we posted about how ATAK has the ability to plot aircraft positions via an RTL-SDR receiving ADS-B.
WarDragon KrakenSDR to TAK Python + Federate TAK Server w/ K2T Developer (KrakenSDR)
Over on his YouTube channel, Aaron, creator of DragonOS and the WarDragon kit has uploaded a video showing the Blah2 passive radar software working with an SDRplay RSPDuo. In the video Aaron shows some setup steps before showing the passive radar range-doppler graph.
Blah2 is passive radar software that appears to be inspired by the KrakenSDR passive software that was removed for regulatory reasons. We note that it is legal for others to publish open source passive radar software, but KrakenSDR cannot legally publish their own open source passive radar software because it would be tied to their own physical product. Providing code would mean they essentially sell an off the shelf passive radar product which is restricted.
The notes in Blah2 specifiy that it currently only supports the SDRplay RSPduo and USRP devices, but in the future they are looking to add support for the KrakenSDR and modified RTL-SDR and HackRF hardware.
Aaron also briefly demonstrated the related adsbdd software, from the same author as Blah2. This software allows a user to convert ADS-B data to delay-doppler truth. Essentially allowing you to confirm is an aircraft position determined via ADS-B is on the range-doppler ellipse determined via passive radar. In the future the author hopes to be able to plot all aircraft in a 2D delay-doppler space graph.
DragonOS FocalX Passive Radar Setup + Test w/ Open Source Code (RSPDUO, RTLSDR, Blah2)
Thank you to RTL-SDR.COM reader Aaron, who recently found a Kraken-to-TAK converter made by "SignalMedic" and "dngrssgnls" which converts the KrakenSDR bearing output data to "Cursor on Target" (COT) or XML format, allowing common TAK interfaces to read and display the data. Currently the converter allows a line of bearing to be displayed in a TAK app, with arbitrary length. The converter consists of a single json file for Node Red. The GitHub readme reads:
Convert data from a Kraken SDR to TAK endpoints
The software will parse information collected by Kraken, convert to COT and XML and send to common TAK interfaces. The length of the line is arbitrary. The line is 6km long, but has no correlation besides bearing to the transmitter. Intersecting bearing lines are necessary for determining the geolocation of a transmitter.
Planned improvements include:
Button for persisting the current line and generating a new UID
Work on filtering out by DOA Angle node
Dashboard for easier updating of Kraken and TAK endpoints
Simplified deployment
We note that most TAK apps may be a little limited for direction finding purposes as they cannot calculate bearing intersections over time, or calculate a bearing grid like the KrakenSDR Android app, and KrakenSDR online web mapper does. However, often a single line of bearing is enough information, especially if there are multiple distributed units contributing bearing data.
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. It can be purchased on Crowd Supply.
TAK (Tactical Assault Kit) is software used by the military and other organizations for visualizing geospatial information such as enemy and friendly positions. Civilian versions of TAK also exist, such as ATAK for Android. Previously we posted about how ATAK has the ability to plot aircraft positions via an RTL-SDR receiving ADS-B.
