Earlier in the year we posted a tutorial showing how to detect the Galactic Hydrogen Line at home with less than $200 in components. All that is really needed is a 2.4 GHz WiFi dish, an RTL-SDR and an LNA. With this setup it's possible to do home science like determining the size, shape and rotational speed of our own galaxy.
Over on YouTube user Nicks Tech Hobby has successfully replicated our tutorial with similar hardware, and has uploaded a time lapse video showing his results. His success confirms that this is a good way to get introduced into radio astronomy. What's also interesting is that it is possible to spot the Hydrogen line energy on the live waterfall even without averaging/integration.
My first successful attempt to detect galactic hydrogen (Hydrogen line)
Thank you to Apostolos for submitting information about his new open source program called "CygnusRFI". CygnusRFI is a tool designed for analyzing radio frequency interference (RFI) with a focus on how it affects satellite ground stations and radio telescopes. We note that in the past we've posted several times about Apostolos' other project called PICTOR, which is an open source radio telescope platform that makes use of RTL-SDR dongles.
Apostolos explains CygnusRFI in the following:
CygnusRFI is an easy-to-use open-source Radio Frequency Interference (RFI) analysis tool, based on Python and GNU Radio Companion (GRC) that is conveniently applicable to any ground station/radio telescope working with a GRC-supported software-defined radio (SDR). In addition to data acquisition, CygnusRFI also carries out automated analysis of the recorded data, producing a series of averaged spectra covering a wide range of frequencies of interest. CygnusRFI is built for ground station operators, radio astronomers, amateur radio operators and anyone who wishes to get an idea of how "radio-quiet" their environment is, using inexpensive instruments like SDRs.
Over on YouTube user Tech Minds has uploaded a video showing how you can determine if you are getting HF interference from a VDSL internet connection going to your house or neighbors. VDSL or Very High Speed Digital Subscriber Line is an internet connection technology that runs over old copper phone wires allowing for a fast broadband connection. The frequencies used by VDSL are between 25 kHz to 12 MHz, and for VDSL2 up to 30 MHz. Unfortunately the frequencies used can result in high amounts of radio interference from RFI radiating from the copper phone lines which is a major problem for HF amateurs and short wave listeners.
In his video Tech Minds uses an SDRplay RSPdx to record a short IQ file of the VDSL interference that he experiences in his home in the UK. He then opens the IQ file in a piece of software called Lelantos, which was developed by a member of the UK amateur radio organization RSGB. If a VDSL signal is present, this tool will determine various bits of information about the interference, and will give you enough information to make a complaint to OFCOM, the UK's radio communications regulator.
DragonOS is a ready to use Linux OS that includes various SDR programs preinstalled. The creator Aaron also runs a YouTube channel that contains multiple tutorial videos for DragonOS. One of the latest videos he's released is a tutorial that shows how to use one of our KerberosSDR (4x Coherent RTL-SDR) units to set up networked direction finding. To do this he uses our core KerberosSDR DSP software, along with RDFMapper, a third party bearing visualization tool with the ability to display bearing from multiple networked direction finding units.
The tutorial goes through the KerberosSDR software install procedure, shows how to set up the various parameters in the software, and then demonstrates it providing data to the RDFMapper software via our open source pyRDFMapper-KSDR-Adapter program. With this setup, you could run multiple KerberosSDR units around a city and use them to locate a signal source rapidly.
DragonOS LTS/10 Bearing Server (KerberosSDR, RDFMapper)
In addition to the direction finding video he's got another video that shows how to use a KerberosSDR and HackRF to simultaneously monitor various signals like home gas meters, ADS-B data, and 433 MHz ISM band devices using programs like rtlamr, rtladsb and rtl_433. What's particularly interesting is how he uses a program called Kismet to manage each radio on the device.
In addition, he's also noted how the default config files provided by goestools do not download EMWIN (Emergency Managers Weather Information Network) images. EMWIN images are not photos, but rather weather forecast and data visualizations that may be useful for people needing to predict or respond to weather. Over on his Github he's uploaded a modified version of goestools which has config files for EMWIN and other image products that might be of interest to some.
If you're interested, Carl Reinemann also has various bits of information about building APT/Meteor satellite RTL-SDR receivers on his main site too. Of interest in particular is his notes on creating wide area composites of NOAA APT images with WXtoIMG which we have posted about in the past.
GQRX is a general purpose GUI based SDR program that is typically used most often on Linux and Mac computers, however it is still possible to install and use it on Windows. Over on YouTube M Khanfar has uploaded a tutorial video that shows a step by step guide on how to get GQRX running on Windows 10.
The process is a little long as it involves an install of Windows GNU Radio, Python, pip and various Python dependencies required by GQRX, as well as setting up the Windows PATH. If you prefer a text guide, the full tutorial is also typed out in the YouTube video description.
Over on YouTube SignalsEverywhere/Harold is back with a new video tutorial that shows users how to set up a SDR# SpyServer with an RTL-SDR dongle. SpyServer is a program included with SDR# that allows you to access your Airspy or RTL-SDR dongle remotely through the internet or local network connection. Thanks to it's compression techniques and that it does most processing on the server side, it requires significantly less network bandwidth compared to a raw IQ server like rtl_tcp.
In the video Harold first shows how to access the SpyServer network in SDR# which consists of many remote SpyServers that have been made accessible to the public for free. He then goes on to explain how you can set up your own SpyServer by simply editing a text config file. He notes that you may need to perform port forwarding on your router if you wish to make the server publicly accessible.
RTL SDR Spyserver Remote SDR Setup Tutorial (on Windows)
It's been a good time for ready to use SDR Linux OS images recently, as we've seen the release of two new images, DragonOS and gorizont-rtlsdr over this lock down period. And now the already popular and mature PiSDR image has also been updated.
PiSDR is a ready to use Raspbian based operating system for Raspberry Pi's which comes pre-loaded with many programs for software defined radios. It currently supports the RTL-SDR, LimeSDR, PlutoSDR, Airspy, and Airspy HF+ and has preinstalled software such as SDR Angel, Soapy Remote, GQRX, GNURadio, LimeUtil, and LimeVNA.
The latest update includes various bug fixes as well the following new features:
Three times smaller.
Verified Compilation on GitHub Actions.
New Software: Quisk, CygnusRFI, rpitx, rtl_433, acarsdec, gpredict, multimon-ng, and leansdr