Category: KrakenSDR

KrakenSDR Low Power FM Transmitter Hunt

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. KrakenSDR is in stock and can be purchased from CrowdSupply or Mouser. More information is also available on our website at krakenrf.com.

In this video we are using a KrakenSDR to hunt for the location of a low power FM transmitter (LPFM) station at 106.7 MHz. These low power FM transmitters are legal as unlicensed transmitters as long as they operate under certain restrictions, the main one being that they transmit at under 1 watt EIRP. LPFM stations are typically operated by local communities or niche radio stations.

Because they are unlicensed, there is no official record and their location doesn't show up in the radio spectrum management database. A requirement of LPFM is that the station broadcast the contact information of the owners regularly, but it can be difficult to locate non-compliant stations that don't do this. But the KrakenSDR makes finding them easy.

The array is 45cm in radius, which is about the maximum that my RAV4 car roof can fit. Some of the antennas sit on a slight curve on the roof, but this appears to have negligible effect. The spacing factor is about 0.19 (optimal is 0.5 - a much larger radius), but even 0.19 is sufficient to find the transmitter fairly easily.

KrakenSDR Low Power FM Transmitter Hunt

 
 

DragonOS: KrakenSDR and DF Aggregator Connected via a 1km WiFi Link

DragonOS is a ready to use Ubuntu Linux image that comes preinstalled with multiple SDR software packages including a tool called DF Aggregator, which can be used for radio direction finding with a device like our KrakenSDR.

In his latest video, Aaron, creator of DragonOS tests out a long range one kilometer WiFi link between a KrakenSDR, and his base station running DF Aggregator. The WiFi link is achieved by using a ALFA Network 802.11ah (900 MHz US) adapter. The remote KrakenSDR is running on a 'DragonDeck', which is a SteamDeck gaming console with DragonOS installed on it.

In the video Aaron shows that when he transmits with his handheld radio, the remote KrakenSDR is able to provide an accurate bearing towards the transmitter. At the end Aaron also briefly tests out automatic speech transcribing via WhisperCPP.

Aarons tests were run together with @VibesGoon who shows a few great pictures of his KrakenSDR setup on his Twitter Feed.

DragonOS FocalX 1km Remote Connect to KrakenSDR/SDR4Space w/ 802.11ah (hackRF, Halow-U, SteamDeck)

Aaron also shows another picture on his Twitter feed, which also shows the SteamDeck.

PySDR Guide on DOA & Beamforming

PySDR is a free online textbook created by Dr. Marc Lichtman which explains many digital signal processing (DSP) and software defined radio (SDR) concepts in a clear, concise and easy to understand way. The guide includes multiple images and animations, as well as Python code examples.

In a recent update, Dr. Lichtman has begun adding a new chapter on Direction of Arrival (DOA) and Beamforming which are core concepts for coherent radio direction finding devices like our KrakenSDR. As with the other chapters the guide is made easy to understand with many images and animations.

The introduction reads:

Direction-of-Arrival (DOA) within DSP/SDR refers to the process of using an array of antennas to estimate the DOA of one or more signals received by that array. Once we know the direction a signal of interest is arriving from, we can isolate it from other signals/interference/jamming.

It is just like isolating a signal in the frequency domain by filtering it, except we are now working in the spatial domain (you can certainly combine both!).

We typically refer to the antennas that make up an array as elements, and sometimes the array is called a “sensor” instead. These array elements are most often omnidirectional antennas, equally spaced in either a line or across two dimensions.

DOA is a subset of beamforming techniques, where as the receiver, we are trying to steer a beam (our receiver’s antenna beam) towards the direction of an emitter. We may also steer a beam blindly across a wide range (e.g., 0 to 360 degrees) to figure out what signals are being received and from what direction.

A visual example of what happens to two signals when the interelement spacing of a direction finding antenna array is reduced below half a wavelength.

Tech Minds: Testing an RTL-SDR Wideband Scanner with WebUI

Over on YouTube Matt from the Tech Minds YouTube channel has put up a video demonstrating an open source program released on GitHub called "RTL SDR Scanner", or "rtl-sdr-scanner-cpp". This program is compatible with RTL-SDR and HackRF software defined radios, and allows users to record multiple analogue FM audio channels within the active bandwidth simultaneously. 

To get a wider bandwidth, you can use a HackRF as your SDR, or you can also use multiple RTL-SDR dongles, or a device like the KrakenSDR which has multiple RTL-SDRs built into it. Alternatively, you can also have the software scan a much larger swath of bandwidth, however this could result in some transmissions being missed. 

The audio is recorded as a wav file, and can be accessed through a web UI. We note that currently only FM recordings are supported but AM may be supported in the future.

RTL SDR Scanner - FULL Bandwidth Recording With WEB UI

KrakenSDR Locates a Repeater Jammer in 1 Hour

Over on YouTubem channel NotaRubicon Productions has uploaded a video describing how a KrakenSDR was used to find the location of a person jamming a repeater site. Amateur radio enthusiasts can utilize VHF or UHF repeater towers, which receive signals from lower power handheld or other radios, and retransmit that signal at high power on a slightly different frequency over a much wider area. Unfortunately malicious people can jam these repeaters by transmitting at the same time as other users, effectively denying use of the repeater by legitimate users.

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. We successfully crowd funded the device on Crowd Supply, and the device is currently available for sale on Crowd Supply, Mouser and direct from our website krakenrf.com.

In this video I read the story of how we caught the jammer that had been jamming our GMRS repeater for months, and how by using the KrakenSDR Radio Direction Finder (RF locator), we were at his house in 1 hour.

The KrakenSDR can track a signal being transmitted from 100Mhz to 1Ghz - so I can track ham repeater jammers, GMRS repeater jammers, ham-radio transmitters, GMRS radios - pretty much any transmitter with a signal strong enough for you to receive.

How The KrakenSDR Located Our Repeater Jammer In 1 Hour. Overview of the KrakenRF Inc. RF Locator

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.

https://www.youtube.com/watch?v=yCU0prz5As4

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.

https://www.youtube.com/watch?v=D7C5_DJkM_k
https://www.youtube.com/watch?v=fiJIhRzG2Os

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.

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.