Tutorial on Using xrit-rx to Receive Weather Images from Geostationary Satellite GK-2A

Over on his website VKSDR has recently released a tutorial about his Linux based xirt-rx software which allows RTL-SDR and other SDR owners receive weather images from the geostationary satellite known as GEO-KOMPSAT-2A (GK-2A). GK-2A is a Korean satellite, hence it is positioned over the Asia-Pacific region, covering Asia, Eastern Russia, Australia and New Zealand. 

To receive images from GK-2A you'll need an RTL-SDR, 2.4 GHz WiFi grid antenna and an L-band LNA. We have an earlier tutorial about receiving GK-2A and GOES geostationary L-band satellites that goes into more detail about the hardware required. 

VKSDR's xrit-rx software decodes the Low Rate Information Transmission (LRIT) signal from GK-2A which provides a 64kbps data stream and full disk images of the earth every 10 minutes. His tutorial explains the various image types that are transmitted, shows a few example images, and shows that some smooth animations can be created with the 144 images received over a day. The rest of the tutorial goes into the software setup, and explains the installation and configuration procedure.

We note that the latest version of xrit-rx now also comes with a nice web based dashboard that allows you to view the latest image, as well as the upcoming image schedule.

Full Disk Images Received from GK-2A via XRIT-RX
Full Disk Images Received from GK-2A via xrit-rxThe new web based dashboard for xrit-rx

The new web based dashboard for xrit-rx

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ARM Radio Code Ported to Free Toolchain

Several years ago in 2015 we posted about the "ARM Radio" by Alberto I2PHD which is a minimalist SDR implementation based on the ARM processor on the STM32F429 discovery board. It was implemented with nothing more than a basic low pass front end, a reconstruction filter for the audio output and some DSP code. With it's low cost ADC it's only able to tune from 8 kHz to 900 kHz, but this is enough to get broadcast AM signals and NDBs. While it may not have the best specs, it's an excellent learning project for SDR DSP and microcontroller programming, and the code is completely open source, although a non-free toolchain is required.

Recently Alberto Garlassi wrote in and wanted to share a re-implementation of the code on a free toolchain. He writes:

Unfortunately the author used the Keil MDK toolchain, this means that it is not possible to change the code without paying for a license. The free version is limited to 32K and this is not enough.

I ported it to the free (don't know how much, certainly GCC + Eclipse) System Workbench, now it is easy for everybody to start where I2PHD left.

I did this several years ago and in the meantime ST and ARM changed many things in their tools and libraries, but it still works ok, I checked.

The complete project is on Github, it should be a matter of downloading the IDE, the libraries and press the debug icon. I'm in touch with Alberto Di Bene I2PHD, he has no objections and told me he's happy about this.

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GNU Radio TEMPEST Implementation Now Available

TEMPEST refers to a technique that is used to eavesdrop on electronic equipment via their unintentional radio emissions (as well as via sounds and vibrations). All electronics emit some sort of unintentional RF signals, and by capturing and processing those signals some data can be recovered. For example the unintentional signals from a computer screen can be captured, and converted back into a live image of what the screen is displaying.

Until recently we have relied on an open source program by Martin Marinov called TempestSDR which has allowed RTL-SDR and other SDR owners perform interesting TEMPEST experiments with computer and TV monitors. We have a tutorial and demo on  TempestSDR available on a previous post of ours. However, TempestSDR has always been a little difficult to set up and use.

More recently a GNU Radio re-implementation of TempestSDR called gr-tempest has been released. Currently the implementation requires the older GNU Radio 3.7, but they note that a 3.8 compatible version is on the way.

The GNU Radio implementation is a good starting point for further experimentation, and we hope to see more developments in the future. They request that the GitHub repo be starred as it will help them get funding for future work on the project.

The creators have also released a video shown below that demonstrates the code with some recorded data. They have also released the recorded data, with links available on the GitHub. It's not clear which SDR they used, but we assume they used a wide bandwidth SDR as the recovered image is quite clear.

Examples using gr-tempest

GR-TEMPEST: GNU Radio TEMPEST Implementation
GR-TEMPEST: GNU Radio TEMPEST Implementation
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Black Hat USA 2020 will be a Virtual Event

Black Hat is a yearly conference about information security related topics. Whilst not as common as in other RF focused conferences, there are often talks related to software defined radio and RF in general. For example, recently they have uploaded videos of talks from their 2018 event and one talk titled "Screaming Channels: When Electromagnetic Side Channels Meet Radio Transceivers" shows how a HackRF SDR can be used to help break the cryptography of bluetooth AES encryption via RF noise unintentionally emitted by components in the transmitter.

Due to the current global pandemic, the conference organizers have decided that the 2020 conference to be held in Las Vegas during August 1-6 will instead be held virtually. They write:

MAY 8, 2020
We have been continuously reviewing the best ways to serve the information security community over the past few months as the global health situation continues to develop. While we will not be meeting in person, we are moving forward with a plan to transform Black Hat USA into an all-virtual event in order to best serve our community.

We're inspired to adapt Black Hat USA in a virtual format that will be available to our entire global community. Our team is working hard to deliver the same level of high-quality Briefings, Trainings and Business Hall programs that Black Hat attendees have come to expect every year.

We believe in the power of gathering our community to share, inspire, and strengthen our industry and are committed to providing that opportunity in August. We look forward to sharing more information about Black Hat’s virtual event soon.

Steve Wylie, Black Hat General Manager

We note that the GNU Radio conference which will be held on September 14 will also be held virtually. 

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Tech Minds: Upgrading to the latest Airspy R2/Mini Firmware

Over on YouTube Tech Minds has uploaded his latest video that shows how to easily update the firmware on Airspy R2 and Mini units. The Airspy R2 ($169) and Airspy Mini ($99) are two software defined radios that can be considered a step up from an RTL-SDR in terms of performance and price. Recently the Airspy developer updated the firmware, and we show the changelog below.

This release improves the overall phase noise, tuning accuracy, dynamic range and spur responses.

What changed:

  • More accurate R820T/2 tuning.
  • Fast R820T/2 register update by only sending the actual changes. Useful for fast scanning.
  • The R820T/2 reference clock is now fed directly from the 25 MHz TCXO. No noise contribution from PLL_A at all when using the internal TCXO.
  • The MCU and ADC reference clock is now using PLL_B of Si5351 in Integer mode with power of two dividers.
  • EXT_CLK now feeds PLL_A for the R820T/2 and PLL_B for the LPC4370 with optimal Integer Mode and power of two dividers.
  • Drive level reduced to 2mA per clock. This significantly reduces the spurs.

Tech Mind's YouTube video shows us how to check the current firmware installed, how to download the latest firmware, and finally how to actually flash the new firmware.

AIRSPY R2 & MINI Software Defined Radio Firmware Update Procedure

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RTL-SDR Blog V3 Units and Antennas Back in Stock at Amazon (Local US Stock)

Just a note that our RTL-SDR Blog V3 units and antennas are now back in stock at Amazon.com with local US stock. There were a few manufacturing and shipping delays related to COVID-19 so they had been out of stock for a couple of months. Currently they are being fulfilled via our partners based in Chicago, and all orders will ship out within 2-business days via USPS First Class. We will look at replenishing the the Amazon Prime warehouses in a few weeks and at the moment we are only shipping to US customers from Amazon. US customers can also order directly from our store at www.rtl-sdr.com/store and this will result in the shipping fee being waived.

If you are based elsewhere in the world, please order directly from our store at www.rtl-sdr.com/store which ships non-US orders direct from our warehouse in China. Alternatively some countries might benefit from our Aliexpress store, which can now utilize the reliable Aliexpress Standard Shipping line.

Our RTL-SDR Blog V3 is an improved RTL-SDR dongle. It includes features like a TCXO, SMA port, software switchable bias tee, built in HF direct sampling mod, aluminum enclosure, improved ESD protection, improved cooling via thermal pad and many other design improvements. The kit comes with a multipurpose dipole antenna which is extremely versatile. It can be used as a standard vertical dipole for terrestrial signals, or can be mounted horizontally in a V-Dipole configuration for NOAA/Meteor LEO weather satellites. It's also easy to mount outdoors through a window for best reception with two mounting solutions included. 

Amazon Links

RTL-SDR Blog V3 Dongle + Multi Purpose Dipole Antenna Set

RTL-SDR Blog V3 Dongle Only

Multi Purpose Dipole Antenna Set Only

RTL-SDR Blog Store

We are also shipping any US orders made from our Worldwide store via our local stock. If you order directly from us you can save $1.99 on shipping.

RTL-SDR Blog Store

Features of the RTL-SDR Blog V3.
Features of the RTL-SDR Blog V3.
The RTL-SDR Blog V3 Set. Includes RTL-SDR V3 dongle, and multipurpose dipole antenna kit.
The RTL-SDR Blog V3 Set. Includes RTL-SDR V3 dongle, and multipurpose dipole antenna kit.
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Running rtl_tcp over the TOR Network

Over on his DragonOS YouTube tutorial channel Aaron has uploaded a video showing how it is possible to run rtl_tcp over the TOR network. TOR is an "anonymity network" which routes your internet traffic through thousands of volunteer nodes in order to make tracing your internet activity more difficult.

Aaron's tutorial shows how to route rtl_tcp traffic through a TOR connection on his Linux distribution DragonOS (although it should work on any Linux distro), and connect to it with GQRX.

However, a major caveat is that the data streaming result is rather poor with there being lots of data drops, probably due to the slowness of the TOR network. Perhaps running a smaller sample rate, or using a more efficient server like Spyserver might work better.  

DragonOS LTS Remote access RTL-SDR over TOR network (Gqrx, rtl_tcp, OpenWRT)

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The 2020 GNU Radio Conference will be held Virtually – Talks Streamed for Free

The yearly GNU Radio Conference (GRCon) is a conference all about the development of GNU Radio and projects based on GNU Radio. GNU Radio is an open source digital signal processing (DSP) toolkit which is often used in cutting edge radio applications and research to implement decoders, demodulators and various other SDR algorithms.

This years 2020 GNU Conference is to be the 10th one ever held and was supposed to take place in Charlotte, NC. However due to the ongoing pandemic the organizers have now decided that it will be held entirely online this year. The starting date is September 14 and the talks and events will probably run for several days. All talks will be streamed for free, however, registering for US$50 will get you access to the live workshops and other events.

There is a great line up of keynote speakers, and if you have a talk that you'd like to submit, submissions are now open. For ideas on what GNU Radio talks are like, you can see full recordings from previous GNU Radio conferences on their YouTube channel playlists.

GNU Radio Conference (GRCon) is the annual conference for the GNU Radio project & community, and has established itself as one of the premier industry events for Software Radio. It is a week-long conference that includes high-quality technical content and valuable networking opportunities. GRCon is a venue that highlights design, implementation, and theory that has been practically applied in a useful way. GRCon attendees come from a large variety of backgrounds, including industry, academia, government, and hobbyists.

GRCon20 will be held starting September 14, 2020 online as a virtual event. The organizing team is hard at work to create a fun and interactive experience.

Our keynote speakers include: Becky Schoenfeld W1BXY, managing editor of QST magazine, Oona Räisänen [ windytan ] hacker of signals and computer programmer, and Jim St. Leger, Director Open Source, Intel.

With an annual program that has broad appeal, GRCon attracts people new to Software Radio just looking to learn more, experts that want to keep their finger on the pulse & direction of the industry, and seasoned developers ready to show off their latest work.

Call for Participation is now open!

Registration

Registration is available now!

Register Here

Refund Policy

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