KerberosSDR App Update: Heatmap + Precise TX Localizing & Turn by Turn Navigation Demo Videos

We have just released an updated version of the KerberosSDR Android direction finding app. If you didn't already know KerberosSDR is our experimental 4x Coherent RTL-SDR product. With it, coherent applications like radio direction finding (RDF) and passive radar are possible. Together with the KerberosSDR direction finding Android app it is possible to visualize the direction finding data produced by a KerberosSDR running on a Pi3/Tinkerboard.

The KerberosSDR hardware is currently in preorder status on Indiegogo for the second production batch, and we expect it to be ready to ship out this month. If you preorder then you'll be able to purchase a KerberosSDR at a reduced price of USD$130. After shipping for batch two begins the price will rise to USD$150.

The new version of the KerberosSDR Android app adds the following features:

  1. Heatmap Grid Plotting
  2. Precise TX location pinpointing when enough data points are gathered
  3. Turn by turn navigation to the RDF bearing direction / TX location
  4. Bearing moving average smoothing

To understand what these features are, we've released two demo videos showing them in action. In the first video we use the new features to find an 858 MHz TETRA transmitter, and in the second video we find a 415 MHz DMR transmitter. The first video explains the new features so we recommend watching that first.

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

KerberosSDR Radio Direction Finding: Heatmap + Auto Navigation to Transmitter Location Demo 2

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SignalsEverywhere: Creating a DIY Upconverter with a HackRF and RF Mixer

Over on YouTube Corrosive from the SignalsEverywhere channel has uploaded a new video showing us how you can make a DIY upconverter using a HackRF as a signal source and a cheap $10 RF Mixer. An upconverter converts lower frequencies into higher frequencies. For example, an upconverter is commonly used to convert HF signals into VHF, so that VHF/UHF only SDRs can receive HF.

In the video he uses the HackRF as a local oscillator source, a cheap RF mixer on a breakout board, and an Airspy as the receiver. In most circumstances if you needed and upconverter you'd just purchase one like the Ham-it-up, or the Spyverter for ~$40. However the interesting advantage of using a versatile signal generator like the HackRF is that it results in an upconverter that can upconvert HF to almost any frequency. Even without any filtering (which is recommended to remove signal images), Corrosive fings that he has excellent HF reception.

This video is an excellent way to learn about how upconverters work.

HackRF and RF Mixer = DIY RTL SDR Up-converter | Basics of the Passive ADE Mixer

 

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SignalsEverywhere: Windows 10 usb_open_error -12 Fix

The process to install an RTL-SDR dongle on Windows involves the simple step of running Zadig and installing the generic WinUSB drivers to the RTL-SDR, which shows up as "Bulk-In, Interface (Interface 0)" in Zadig.

However we find that people sometimes accidentally use Zadig to install WinUSB to "Bulk-In, Interface (Interface 1)" by mistake. Installing WinUSB to this interface can break your installation, and it can cause the RTL-SDR to display a "usb_open error -12" on command line software, and can cause problems connecting to the device on GUI software like SDR#.

Over on YouTube Corrosive from the SignalsEverywhere YouTube channel uploaded a very useful video that shows how to fix this problem.

RTL SDR Drivers On Windows 10 2019

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Creating Wide Area Composite Images with WXtoIMG + Weather Satellite Failure Updates

With so many independent people receiving weather satellite images from the NOAA satellites daily, an interesting collaborative task is to stitch these images together to create a wide area composite image. Fortunately the WXtoIMG software already has stitching as a feature.

Over on his website "usradioguy" has created a tutorial explaining how to use WXtoIMG to stitch together multiple NOAA weather satellite images that have been uploaded to individuals websites. As well as the tutorial he has created a table of people's websites that contain recent and the required "pristine" processed images that can be used for stitching.

NOAA Weather Satellite Composite by Jeff Kelly (New Jersey, US), Mike Kimzey (Philadelphia, US), David Kunz (San Francisco, US), Cornelius Danielsen (Norway), Alan Hinton (UK), Michael Sørensen (Denmark), and Hans-Juergen Luethje (Germany).
NOAA Weather Satellite Composite created with images from Jeff Kelly (New Jersey, US), Mike Kimzey (Philadelphia, US), David Kunz (San Francisco, US), Cornelius Danielsen (Norway), Alan Hinton (UK), Michael Sørensen (Denmark), and Hans-Juergen Luethje (Germany).

Weather Satellite Failure Updates

We also wanted to provide a brief update on some weather satellites that we RTL-SDR users often receive.

NOAA 15: About two weeks ago NOAA 15 failed and was producing glitched images. However after a few days it came right again, only to have failed again at the end of last month. It appears that the camera scanning motor is getting stuck due to being low on lubricant as the satellite is now well past it's intended life cycle at 11 years old. If you're interested, some info on how the camera on these satellites works can be found here. There is currently no plan for a fix, the only hope is to wait and see if the motor unsticks.

Meteor M2-1: Meteor M2-1 has also recently suffered problems yet again with it's orientation control, and we're regularly seeing off-axis or distorted images that show the curvature of the earth. Over the weekend it was turned off, and should be reset this week. This problem seems to occur and be fixed often, so hopefully it will be back online soon.

Meteor M2-2: The recently launched Meteor M2-2 is functional, but it is still in the testing phase, so is sometimes being turned off. Do not be alarmed if no signal is received sometimes.

GOES-17: GOES-17 is reported to be experiencing problems with it's infrared camera due to a blocked heatpipe, however it appears that they are able to work around this issue and obtain 97% uptime.

A Distorted Meteor M2-1 Image from R4UAB Blog.
A Distorted Meteor M2-1 Image from R4UAB Blog.
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Using an RTL-SDR, RF Fingerprinting and Deep Learning to Authenticate RF Devices

Every device that transmits radio waves has a unique and identifiable RF fingerprint which occurs due to the very slightly variations in the hardware manufacturing process. This means that devices using identical transmitters of the same make and model can still be differentiated from one another.

Nihal Pasham has been using this knowledge as a way to securely identify IoT sensors and other RF devices like car keyfobs. The idea is that these unique RF fingerprints are immune to authentication spoofing which could be used to create a fake transmitter with fake data. He suggests that RF fingerprinting could be used as an additional authentication check for low cost IoT devices with only basic security.

In order to recognize the minute differences in the RF fingerprints of different devices Nihal notes that a good pattern detection algorithm is required, and that a deep learning neural network fits the bill. Using neural network software Tensorflow, and an RTL-SDR for signal acquisition, he was able to train a proof of concept neural model that was able to classify two test transmitters with 97% accuracy.

Training a Deep Learning Neural Network with an RTL-SDR for RF Fingerprinting
Training a Deep Learning Neural Network with an RTL-SDR for RF Fingerprinting

In the past we've seen similar experiments by Oona Räisänen who used an RTL-SDR to fingerprint several hand held radios heard on the air via small variances in the power and frequencies of each radio's CTCSS tone. Using simple clustering techniques she was able to determine exactly who was transmitting based upon the unique CTCSS.

In a somewhat similar fashion, Disney Research has also been working on a RF fingerprinting technique that uses an RTL-SDR based wrist watch to identify what particular electronic devices the wearer is touching.

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LimeRFE WSPR Tests

The LimeRFE is a power amplifier and filter bank solution designed for the low cost TX capable LimeSDR software defined radios. It has multiple bands from HF all the way up to 3.5 GHz, and is capable of putting out about 2W on the HF bands. Currently LimeRFE is crowdfunding over on CrowdSupply with a cost of US$599 or alternatively there is now a cheaper unit for US$449 without support for the cellular bands. The campaign is active for 4 more days from the time of this post, and after that the price is due to rise by another US$100.

The team at LimeMicro sent a unit to Daniel Estévez (EA4GPZ) for testing, and he has recently posted about his results and thoughts when using the LimeRFE for WSPR transmission with a 15m long wire antenna. Daniel connected his LimeRFE to his LimeSDR and used WSJT-X piped into SDRAngel via Pulseaudio to transmit WSPR on the 10m band. He notes that for lower bands, the LimeRFE will still need additional low pass filtering to attenuate harmonics. SDRAngel cannot yet control the LimeRFE so he also created a simple Python script for this purpose.

Unfortunately Daniel's unit only achieved 25dBm instead of the advertised 33dB, but in LimeMicro's post they note that they believe that this is due to shipping damage. However, even with only 0.3W power, Daniel's transmissions from Madrid were able to be picked up in the Canary Islands, Netherlands and Northern England.

WSPR Range with a LimeRFE (reduced 0.3W output)
WSPR Range with a LimeRFE (reduced 0.3W output)
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Using SDR For QO-100 Satellite Operation

Es’hailsat, otherwise known as QO-100 is the first geostationary satellite with an amateur radio payload on-board. The satellite contains both a Wide Band transponder for experimental modes and DVB-S Digital Television and a Narrow Band transponder used mostly for SSB voice and some digital mode contacts with other amateur operators. If you’re unfamiliar with this satellite we’ve covered it in previous articles, like in [Es’hail Transponder Now Active]

While many choose to use a transverter connected to a traditional amateur transceiver, others have turned to use Software Defined Radios to complete their satellite ground stations.

[Radio Innovation] posted a video back in March showing his contact on QO-100 using a LimeSDR Mini as the 2.4 GHz transmitter and a 10 GHz LNB for the downlink.

The PlutoSDR has been frequently seen used for QO-100 satellite operation on the Wide Band transponder due to its ease of DVB-S transmission utilizing software such as [DATV Express] but more recently there have been more and more operators turning to SDR for their day to day satellite operation.

It will be interesting to see how these stations evolve, perhaps by the time North America has access to a similar satellite, we’ll be prepared to operate it.

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Updated Meteor M-N2-2 Tutorial and Decoder Now Available

Thank you to Happysat for submitting the following information about the updated LRPT decoder for Meteor M-N2-2. He has also provided a link to his very useful Meteor Satellite reception tutorial.

Today the official LRPT-Decoder V42 ready for release :)

Before we did use a older internal debug version from 2014, because this one was still in development.

This version 42 of LRPTDecoder will work with both Meteor M-N2 and Meteor M-N2-2.

Example ini configuration files for other modes are attached in the archive.

http://happysat.nl/LRPT_Decoder_v42.rar

Howto overhere http://happysat.nl/Setup_Meteor/Setup.html

Author of LRPT_Decoder is Oleg ROBONUKA.

The new Meteor M-N2-2 Decoder + Sample Image
The new Meteor M-N2-2 Decoder + Sample Image
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