Finding Multiple GSM Base Station Transmit Towers with the Multi-VFO Feature

In this video we're using KrakenSDR to find the location of GSM base station transmit towers for four frequencies. We're also using the multi-VFO feature to capture the bearing data of these four frequencies simultaneously which can save us some search time.

Once we've found the first transmit tower, we already have some logged bearing data that can be used to help us find the second tower faster. Then the third and fourth towers are even faster to find due to even more data having already been collected.

Interestingly, it also turns out that the first frequency we search for is actually being used by another tower that we pass along the way back. The location of this tower was picked up on the drive back to the first tower. It's possible that these two towers which are a few kilometers apart are covering different areas with directional antennas.

Also note that the first two transmitter searches use the "auto-zoom" map camera feature, which will automatically zoom the screen to show both the vehicle and estimated transmitter location. The second half uses the standard free camera mode.

This is on a new build of the App which is currently in testing, so some things may look slightly different to the currently released version. The new app version will have some minor feature improvements.

KrakenSDR Low Power FM Transmitter Hunt

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 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.

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 again.

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.

F4IPO Demo

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

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.

F1MIJ Demo

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

Manuel Lausmann Unboxing Video

In this video Manuel Lausmann unboxes the KrakenSDR.

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.

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.