Category: Applications

Sanchez Updates: Combine Weather Images from GK-2A, Himawari-8, GOES 16/17 Satellites into one Composite Image

Back in August we posted about the release of Sanchez, a tool originally designed to apply a color underlay image to grayscale infrared images received from geostationary weather satellites such as GOES 16/17, Himawari-8 and GK-2K. The tool has recently been updated with some very nice new features.

One of the new features is the ability to composite together images obtained from multiple satellites in order to form a full equirectangular image of the earth with live cloud cover. Another feature is the ability to use two or more images from different satellites to reproject back to geostationary projection at a specified longitude, essentially creating an image from a virtual satellite.

Image composed of GK-2A, Himawari-8, GOES-16 and GOES-17 satellites (full resolution images available at https://github.com/nullpainter/sanchez/wiki/Sample-images

TechMinds: The Langstone Project – SDR Transceiver with PlutoSDR

Over on his YouTube channel Tech Minds has uploaded a video introducing and demonstrating the Langstone Project. Langstone is a standalone homebrew SDR transceiver project by Colin Durbridge (G4EML) which at its most basic implementation is based on an Adalm PlutoSDR, Raspberry Pi 4 and 7" LCD touchscreen. 

In the video Tech Minds shows how to install the Langstone Pi4 software on the SD card, and then demonstrates it in action. He also notes that the output power of the PlutoSDR is too low for any real communications, however it is possible to add an amplifier and appropriate band filtering. To help with that, the software makes us of the GPIO pins on the Pi4 which can be used to switch in optional band filters.

Langstone Project - SDR Transceiver using an Adalm PlutoSDR

Decoder for Geostationary Elektro-L Weather Satellites Released

Elektro-L is a range of Russian geostationary weather satellites. Elektro-L1 and L2 were launched in 2011 and 2015 respectively, and Elektro-L3 was launched more recently in December 2019. Currently only Elektro-L2 and L3 are in operation. Like it's NOAA GOES, Himawari and GK-2A cousins, Elektro-L satellites beam back full disk images of the entire earth.  Elektro-L2 is positioned to cover South America, Africa and Europe, whilst Elektro-L3 covers the East of Africa, Eastern Europe, Russia, Middle East, Asia and the West of Australia.

Elektro L2 and L3 Coverage from https://www.wmo-sat.info/

Recently @aang254 has been Tweeting that he has managed to get an Elektro-L decoder working. The decoder is open source and available on GitHub and Windows builds are already available. He notes that he's still working on the demodulator, but that should be released tomorrow. This decoder is great news as now Europeans now have an opportunity to receive full disk images. There is no full guide yet on how to use the decoder, but we expect that one will be released soon.

We note that according to wmo-sat.info the Elektro-L satellites transmit at ~1693 MHz, and have a 2 MHz wide HRIT and 200 kHz wide LRIT mode. So the signals should be able to be received with an RTL-SDR and appropriate LNA. EDIT: Unfortunately it seems that wmo-sat.info may have incorrect information, and that Elektro-L requires X-Band hardware to receive these images. While not totally impossible, an X-Band satellite SDR setup is a bit more difficult to put together compared to the L-band SDR setup used by GOES and GK-2A.

John’s Windows 10 NOAA Weather Satellite Software Guide for RTL-SDR

Thank you to John First for submitting his guide all about the setup and use of the software required to receive NOAA weather satellite images on Windows 10 (pdf file) with an RTL-SDR dongle. John's guide covers the use of SDR# for receiving the signal, WXtoIMG for decoding the signal, and Orbitron for tracking the satellite and automatically tuning SDR# when a satellite is in range.

He also explains the use of the VB-Audio Virtual Cable for piping audio between SDR# and WXtoIMG, as well as the DDE Tracking and Scheduling Plugin for interfacing SDR# with Orbitron, and finally how to do NTP clock synchronization to ensure the local time is accurate.

An Excerpt from John's Guide
An Excerpt from John's Guide

Introducing the Radio Resilience Competition

Thank you to Matt Knight for submitting news about the Radio Resilience Competition which is all about finding ways to building the best wireless PHY layer via SDR. Anyone around the world can participate from the comfort of their own home, as the competition is run entirely via a GNU Radio RF simulator system. Matt writes:

The Radio Resilience Competition is a community-focused Software Defined Radio competition that is all about building the most interference-resistant, highest-performance waveforms possible.  Inspired by DARPA's Spectrum Challenges, it goes back to basics by focusing on the foundational layer of all wireless communications -- the PHY.  Registration is open now on our homepage!

For your readers, IMO the most exciting dimension of the Radio Resilience Competition is that it takes place entirely on virtual infrastructure.  We decided to design the competition this way to set the lowest possible barrier to entry, and to draw the biggest competitor pool possible.  DARPA's challenges relied on big expensive RF emulators built on real radios and supercomputers which, despite being immensely cool, capped the total number of competitors and had some material drawbacks.  Furthermore, we open sourced our RF simulator so competitors can run it locally and rapidly iterate on their designs.  We hope the simulator will have uses beyond the competition as well.

The Radio Resilience Competition is organized by Sytse Sijbrandij, who in an entirely separate capacity from running this competition is also the CEO of GitLab.  Sid envisioned the competition after learning about unlicensed spectrum and becoming an SDR hobbyist himself.

We presented the Radio Resilience Competition at GNU Radio Conference on Monday.  Here's a link to our talk if you are interested -- it goes into more detail about the conception of the competition, as well as the infrastructure we built for it.

GNU Radio Conference 2020 - Monday September 14th

Screenshot of the Radio Resilience RF Simulator

The SETI Institute and GNU Radio Join Forces

The institute for the Search for Extraterrestrial Intelligence (SETI) and GNU Radio are joining forces. SETI are an organization that uses radio telescopes to search for radio signals that may have been generated by extraterrestrial intelligence. As part of a transition from proprietary hardware to cheaper more capable off the shelf hardware such as USRP SDRs and GPU processors, SETI are beginning to make more use of the open source GNU Radio DSP processing suite. The use of GNU Radio will also allow other researchers and hobbyists at home to possibly help with their own analysis.

In the Zoom meeting below SETI and GNU Radio leaders discuss the partnership, also noting the importance RTL-SDRs have played in the advancement and popularisation of GNU Radio, as well in the general advancement of radio education.

SETI Institute and GNU Radio Join Forces

Graphing Data from a Weather Station via RTL-SDR and Home Assistant

Over on YouTube user mostlychris has uploaded a helpful tutorial video show how to use an RTL-SDR to collect data coming from a personal weather station and graph it on the home automation software known as Home Assistant.

To do this he uses an RTL-SDR on a Raspberry Pi running rtl_433 which receives and decodes the weather station data. He then configures rtl_433 to output data in the MQTT protocol which Home Assistant can receive and understand.  Finally he configures Home Assistant to plot the received data. The tutorial is comprehensive covering every step required from start to finish.

Take charge of your own Ambient weather data with Raspberry Pi, MQTT, and Home Assistant.

33% OFF Sale: Ultra Stable Bullseye LNB for QO-100/Es’Hail-2

Back in May we started selling the Bullseye LNB on our store, which is an ultra stable LNB for receiving QO-100 and other Ku-Band satellites/applications. We have recently managed to secure a good deal from the supplier. However, our storage warehouse is now low on space and we are hence running a 33% off stock clearance sale with the unit now priced at only US$19.97 including free worldwide shipping to most countries. 

To order the product, please go to our store, and scroll down until you see the QO-100 Bullseye TCXO LNB heading. Alternatively we also have stock via our Aliexpress store or on eBay.

What is QO-100 and an LNB?

QO-100 / Es'hail-2 is a geostationary satellite at at 25.5°E (covering Africa, Europe, the Middle East, India, eastern Brazil and the west half of Russia/Asia) providing broadcasting services. However, as a bonus it also has the world's first amateur radio repeater in geostationary orbit. Uplink is at 2.4 GHz and downlink is at 10.5 GHz.

Most SDRs do not tune all the way up to 10.5 GHz, so an LNB (low noise block) is typically used, which contains the feed, an LNA, and a downconverter which converts the 10.5 GHz frequency into a much lower one that can be received by most SDRs.

What's special about the Bullseye LNB?

In order to properly monitor signals on QO-100 an LNB with a Temperature Compensated Oscillator (TCXO) or other stabilization method is required. Most LNBs have non-stabilized crystals which will drift significantly over time on the order of 300 PPM with temperature changes.  This means that the narrowband signals used on QO-100 can easily drift out of the receive band or cause distorted reception. Software drift compensation can be used to an extent, but it works best if the LNB is somewhat stable in the first place. It is possible to hand modify a standard Ku-band LNB by soldering on a replacement TCXO or hacking in connections to a GPSDO, but the Bullseye LNB ready to use with a built in 1PPM TCXO and is cheap.

Reviews

In the past Tech Minds has reviewed this product favourably in the video shown below. In a second video he has also shown how the Bullseye can be combined with a transmit helix in order to create a dual feed uplink + downlink capable antenna.

Ultra Stable Bullseye LNB For QO-100 Es Hail2 10 kHz

F4DAV has also reviewed the unit on his website, concluding with the following statement:

As far as I know the BE01 is the first affordable mass-produced Ku-band TCXO LNB. These early tests suggest that it can be a game changer for amateur radio and other narrowband applications in the 10 GHz band. The stability and ability to recalibrate should allow even unsophisticated analog stations to tune to a 5 kHz channel and remain there for hours at a time. For SDR stations with beacon-based frequency correction, the absolute accuracy removes the need to oversample by several hundred kHz or to scan for the initial frequency offset.

There are also several posts on Twitter by customers noting good performance

Official Feature List + Specs

Features

  • Bullseye 10 kHz BE01
  • Universal single output LNB
  • Frequency stability within 10 kHz in normal outdoor environment
  • Phase locked loop with 2 PPM TCXO
  • Factory calibration within 1 kHz utilizing GPS-locked spectrum analyzers
  • Ultra high precision PLL employing proprietary frequency control system (patent pending)
  • Digitally controlled carrier offset with optional programmer
  • 25 MHz output reference available on secondary F-connector (red)

Specifications 

  • Input frequency: 10489 - 12750 MHz
  • LO frequency 9750/10600 MHz
  • LO frequency stability at 23C: +/- 10 kHz
  • LO frequency stability -20 - 60C: +/- 30 kHz
  • Gain: 50 - 66 dB
  • Output frequency: 739 - 1950 MHz (low band) and 1100 - 2150 (high band)
  • Return loss of 8 dB (739 - 1950 MHz) and 10 dB (1100 - 2150 MHz)
  • Noise figure: 0.5 dB

We note that an external bias tee power injector is required to power the LNB as it requires 11.5V - 14V to operate in vertical polarization and 16V - 19V to operate with horizontal polarization. The bias tee on the RTL-SDR Blog V3 outputs 4.5V so it is not suitable.