Khanfar Spot Scanner is a powerful and feature-rich spectrum analyzer designed for radio frequency enthusiasts, wireless security researchers, and professional RF engineers. Supporting multiple SDR hardware devices including RTL-SDR, Airspy, and HackRF, this software provides comprehensive spectrum visualization, automated signal detection, and in-depth analysis reporting.
Khanfar Phase-Based DF is advanced direction finding software that uses phase difference analysis to determine the bearing of radio signal sources. Unlike traditional direction finding systems that rely on directional antennas and signal strength comparison, this software utilizes an array of omnidirectional antennas and sophisticated signal processing algorithms to analyze the phase relationships between received signals.
We want to add to this a note that we're not entirely sure how this software can possibly work as phase based direction finding with RTL-SDRs requires synchronized clocks, and sample and phase alignment to be performed via a correlation with a noise source first which this software does not enable. Without those steps taken results will be totally random. We gave this software a brief test with a KrakenSDR, but as expected, did not see the results we expected. We're keen to hear feedback from other users.
Khanfar RTL-SDR IQ Live+Rec+Playback is a powerful, feature-rich spectrum analyzer application designed for RTL-SDR devices. This professional-grade software provides real-time RF spectrum visualization with GPU-accelerated rendering, comprehensive IQ data recording capabilities in multiple industry-standard formats, and advanced playback features for signal analysis. With IQEngine and IQ Analyzer integration, you can seamlessly export your recorded signals for comprehensive online analysis, visualization, and collaboration.
Recently, on Feb 21, we posted news about the release of some spectrum analysis and FM demodulator software from M. Khanfar. Now he has just released his latest software "Khanfar Direction Finder" (scroll to the end of the page), a Windows radio direction finding tool for RTL-SDR dongles.
Khanfar Direction Finder appears to work on the principle of power measurements through the use of directional antennas. Four directional antennas are connected to four RTL-SDR dongles positioned in the N/S/E/W directions.
The antenna pointing towards the signal source will receive it stronger and the antenna pointing away from it will receive it weaker. The two other antennas may receive the signal with some intermediate strength based on the angle. The software automatically combines the power information from all four antennas, resulting in a bearing.
The 'Quintet' version of the software also contains a map that can be used to plot the determined bearings.
Both versions of the software are free to download but not open-source. As mentioned in the previous post, antivirus software can flag M. Khanfar's software as suspicious. We suspect these are false positive results due to the PyInstaller system used to create the exe, but please take your own precautions just in case.
Khanfar Direction Finder Compass ScreenKhanfar Direction Finder Map Screen
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 Crowd Supply our KrakenSDR is currently reduced by 15% for Black Friday. The sale lasts until November 30, or while stocks last. This brings the price of the KrakenSDR down to US$424, down from the regular US$499 pricing. The companion antenna set is also reduced from US$199 down to US$169.
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.
