SignalsEverywhere: Measuring Filters with RTL-SDR, a Noise Source and Spektrum

In her latest video Sarah from the SignalsEverywhere YouTube channel describes how it is possible to use an RTL-SDR to measure RF filters when combined with a noise source and the Spektrum SDR software. In the video Sarah comprehensively explains how to set all the various parameters in Spektrum, before demonstrating a filter measurement with a noise source. Sarah explains how the power measurements may not be entirely accurate, however it is enough to get some idea about the shape of a filter.

Measuring Filters With RTL-SDR and Noise Source. Spektrum SDR Spectrum Analyzer

Gorizont Linux Updated to 2022.1 Edition

Thank you to Steve Cox, creator of the Gorizont Linux distribution for letting us know that is has now been updated to the 2022.1 Edition. Gorizont-linux is an RTL-SDR focused Linux distribution based on Xubuntu 20.04 LTS. It comes in a bootable .iso image for easy installation. Steve writes:

[Gorizont-linux] is still an Xubuntu 20.04 LTS based bootable .iso image for RTL-SDR only, but I've put a lot more work into writing instructions in simple English, refining things and freshening everything up to the latest available release. Here are some highlights:

gqrx 2.15.8
SigDigger 0.3.0
Universal Radio Hacker 2.9.0
gqrx-scan
Welle.io 2.4 for all your DAB and DAB+ needs.
guglielmo v0.3 for simple FM radio and DAB reception - fast, quick and light.
Baudline
fldigi
fmsg
Due to multiple issues with linux versions of Dream DRM, Dream DRM is now installed as a Win 32 .exe running under wine. It works!
w-scan for creating DVB-T/ATSC/etc. scan files for DVB TV viewing using VLC.

Various extra utilities in home folder and command line path
Much clearer instructions and scripts in simple English.

NOTE: Due to current events, gorizont linux now ships with networking disabled on boot. To use internet in a trusted environment, left-click on networking icon to the left of the battery indicator and click 'Enable Networking'.

If I was about to have to flee my home with little more than a laptop and a rtl dongle, this would be my distro of choice for staying in touch with the outside World - fast and easy to use,  yet packed with (other people's) good software.

Running an RTL-SDR on an old OpenWRT Router

With the rising cost of computing hardware like Raspberry Pi's, Jaime Badillo decided to instead make use of one of a cheap old router, and set it up as an RTL-SDR server. To do this, Jaime took his old router and installed on it the free open source firmware OpenWRT, which is essentially a Linux operating system. Once this was completed, he was able to SSH into the router and install the RTL-SDR drivers and rtl_tcp software just as he would with a Raspberry Pi 4.

Jaime has uploaded a tutorial document that shows how to installed OpenWRT, how he configured the network settings and how he installed the RTL-SDR drivers and connected to rtl_tcp remotely via SDRSharp. The tutorial is written in Spanish, however we have uploaded an English Google translated version here. Jaime has also uploaded a YouTube video showing the router server in action.

SDR# receiving data from rtl_tcp running on an old router.

Open-Weather: Contribute to a Snapshot of the Climate Crisis Through NOAA Satellite Imagery

Open-weather is an art project made up of a community of volunteers who capture NOAA weather satellite images with RTL-SDR or similar devices. The images are then collected and stitched together to form a snapshot of the planet, and to be used in various art projects. We have previously posted about some related art projects that the team behind open-weather have done in the past.

Receiving NOAA satellite images may now be run of the mill for many of us technically minded people who have been in this hobby for a while, but one of the ideas behind open-weather is to reach out and inspire people from any background to try and receive satellite weather images. This includes people and communities in the arts that may not be technically minded at all. To achieve this the team has created easy to understand guides, hosted workshops, and created artwork and performances based around the reception of these satellite images.

In a recent article on theconversation.com, the team describe how they collected 38 images from 29 volunteers, across 14 countries and six continents on the first day of the COP26 climate conference. By involving more people in the process of essentially watching the earth from afar, they hope to inspire climate responsibility and to put some thought behind how we are affecting and being affected by the changing environment. An excerpt from the article is pasted below:

This snapshot included a cyclonic weather system curling around the UK, dust clouds sweeping the Indian subcontinent, and the glaciers of the Patagonian Andes, which have been shown by geographer Bethan Davies to be rapidly receding and thinning in response to global warming.

...
 

These satellite images and field notes demonstrate that the climate crisis feels different depending on who you are and where you live. In some places, dry seasons are expanding. Elsewhere, it’s clouds of dust, increasingly volatile storms, or health effects triggered by the air that we breathe.

As politicians fail to respond to the climate emergency, a growing community of Earth-watchers has practical and political potential. Together, we might learn to be collectively responsible for, and accountable to, the environments we are changing.

Sasha Engelmann of Open-Weather receives a NOAA Satellite Image.

A New Aftermarket Airspy HF+ Discovery Aluminum Enclosure for Sale

Thank you to Nobu who has submitted news about the release of his new product, a machined aluminum enclosure for the Airspy HF+ Discovery. The Airspy HF+ Discovery comes by default in a plastic enclosure. Although the HF+ Discovery does not need a metal enclosure to perform well in terms of PCB noise rejection, a metal enclosure gives the product a much more premium feel, and aesthetically looks great. Nobu also mentions that the metal enclosure may help with heat dissipation.

The product is only available on Amazon Japan and may show no stock for international customers. If you are outside of Japan, to be able to purchase you may need to use a Japanese market buying agency, many of which can be found online.

Aftermarket Aluminum Airspy HF+ Discovery Enclosure.

@lambdaprog, creator of Airspy products mentions that this enclosure may help with Airspy HF+ Discovery devices running 24/7.

Radio Related News Occurring in the Russia-Ukraine Conflict

In the current Russia-Ukraine conflict we've seen several noteworthy radio related events occurring over the last few days, mostly throughout Twitter.

Russian HF Bomber Communications

As mentioned in the previous post it has been found that since the start of the invasion, Russian Strategic bombers have been very active on USB voice at 8131 kHz. We've even seen a security firm predict air raid siren activations based on increased bomber HF activity. 

Russian Military HF Frequencies Jammed by Activists

It has been observed that several Russian military HF stations including the famous UVB-76 Buzzer have been jammed with either the Ukrainian national anthem, or various meme-type songs. It is likely that these stations are being jammed mostly by civilian activists, or members of the activist hacker collective known as Anonymous, rather than any military organization.

The UVB-76 Buzzer is a famous and mysterious numbers station that plays a buzzing sound and sometimes voice. It can be received from all over the world. Via civilian investigations, and through the use of the KiwiSDR TDoA direction finding functionality, it has been found to be transmitted from a location just north of St. Petersburg, and is assumed to be a military signal of some sort.

We've also seen waterfall text based jamming:

Using KiwiSDRs you can listen to these jammed stations yourself remotely through public internet connected SDRs in Europe. Some known frequencies are listed here and here

We note that there have also been reports about fake Russian frequencies being posted on the internet.

We assume most jamming is happening from outside the warring countries, and it is unknown how far the jamming signals extend onto Russian or Ukrainian territory, or how much of an impact they are having on Russian operations.

Russian State TV Hacked

Twitter account Anonymous TV has reported hacking Russian state TV to show citizens what is actually happening in Ukraine. It's unknown if this was a hack via TV transmissions being overpowered by another signal, or a computer hack.

Starlink Activated in Ukraine

A few days ago Elon Musk and SpaceX activated their Starlink wireless satellite internet system in Ukraine, and have sent over a shipment of ground terminals. This is useful as even if the local wired internet were to be destroyed, or be censored by Russia, the Starlink system will be able to connect to uncensored internet as long as there is power. 

An account of a Ukrainian engineer and RF hobbyist recently Tweeted his success at getting his Starlink system up and running from his home in Ukraine. We decided not to link to his Twitter account in this post, just in case he needs to delete his account for safety in the future as he appears to be very close to the bombing.

Viasat Satellite Service Experiences Cyberattack and Outages

Viasat, another provider of satellite internet services in Ukraine region appears to have been subject to a DDOS cyberattack, causing outages to it's satellite internet service in the European region.

SSTV Activism Seen On Russian Meridian Satellites

Meridian satellites are a "family of telecommunications satellites for civil and military use developed by Russia in the 2000s placed in a Molniya Orbit" (Wikipedia). A tweet by Scott Tilley @coastal8049 has noted that they have seen reports of SSTV activist activity occurring on the 484 MHz Meridian transponders. 

Scott Tilleys Twitter feed also shows some interesting other pieces of news and information, including frequencies and orbits of Meridian satellites, images of a destroyed Russian command and control satellite communications vehicle, and links to now deleted, but Google cached pages with information about Russian satellite communication systems.

APRS Activism against Russia causes APRS-IS DDOS

Amateur radio operators can use a system called APRS to communicate with text and packet data globally through internet connected radio repeaters. A few days ago it appears that anti-Russia activists flooded the APRS-IS (Automatic Packet Reporting System-Internet Service) system with bogus packets targeting Russian coordinates, which unintentionally resulted in a denial of service (DOS) event on APRS trackers like aprs.fi

DARC Urges Safety First for Ukraine and Foreign Amateur Radio Hobbyists

The German ham-radio association known as DARC has issued a warning to Ukrainian hams, and to foreign hams who may receive from them. Amateur radio operations are currently banned in Ukraine due to wartime laws.

Poland Amateur Radio Society Provides WinLink HF Email Service

In response to geopolitical threats, the Poland Amateur Radio Society has set up a HF WinLink email system, aimed at provided email services to amateur radio operators that could be cutoff from internet email services. It appears this may be aimed at helping Ukrainians communicate, however in these modern days of electronic warfare, it is important to take into account the warning from DARC above too as transmitting stations could easily be located by Russian electronic warfare forces.

Dear HAM operators, in the face of the latest threats in our region and a possibility of an incoming wave of refugees, with over 2 mln already living in Poland, we would like to remind you that we are at your disposal.

If you are a licensed amateur radio operator, you can send information by e-mail to your relatives in Poland or Emergency Services with via the Winlink system, which works on HF bands, independently of access to the local ICT infrastructure https://winlink.org/WinlinkExpress.

We advise you to download the software, install it and check its operation.
Polish WinLink nodes are QRV on 160,80,20m
SR5WLK dial frequency 3595,5 kHz USB
SR3WLK dial requency 14111 kHz USB
SP3IEW dial frequency 1865 kHz USB

If we receive information about the cut-off of the Internet in the region in danger, we will be QRV daily as SP0MASR @ 18-20 UTC on the frequencies 3770 kHz +/- QRM, 7110 kHz +/- QRM. In such a situation, please communicate in Polish or English.

We are here to serve you.

Shortwave Listening Updates

The excellent SWLing.com blog has also provided some updates on shortwave, including news that WRMI have resumed broadcasts of Radio Ukraine International, Ukrainian state radio resumes broadcasting at 549 kHz, and that the BBC adds to new broadcasts to Ukraine.

Russian Oligarch Jets Tracked with ADS-B

An activist has set up a Twitter account to track the private jets of Russian Oligarch's via ADS-B. ADS-B aircraft data can be used to track aircraft locations, and these signals are typically received with low cost SDRs like RTL-SDRs. The project appears to use data sourced from adsbexchange.com which is known to be one of the only ADS-B aggrators that does not censor data.

The 7055 kHz 'Radio War' Frequency Sees Increase in Activity

In has been reported that the 7055 kHz LSB amateur radio frequency has been used by Ukrainian and Russian amateur radio operators for some time now to insult each other in a 'radio war', and recently activity has significantly increased. Other frequencies involved include 7050 kHz LSB and 3731 kHz.

Captured Equipment Shows Russian Radio Hardware In Use

A recent tweet shows a photo of hardware supposedly captured from Russian forces. Of interested is a Russian R-187PI Azart, a handheld digital software defined radio.

At the same time unconfirmed reports suggest that some parts of the Russian army may be relying on civilian Baofeng radios.

Russian Bomber HF Activity, Amateur Radio / SDR Hobbyist Warning Again

With Russian missiles now falling in the Ukraine it seems that the worst has occurred and a full scale invasion has started. We wish for the safety of all Ukrainian citizens and to that end we wanted again to reiterate our safety warning to all SDR owners and amateur radio operators in the Ukraine that we put out three weeks ago. Please remember that last year a Crimean resident was arrested and is currently imprisoned by Russian forces for using RTL-SDR and scanner radios to listen to the airband. Crimea was a previous territory of the Ukraine annexed by Russian forces in 2014.

Along with Ukraine's declared state of emergency, one of the conditions is that all transmitting radio amateur activities must cease. We would also strongly recommend ceasing any public facing receiving activities, including ADSB and WebSDR feeds etc.

We are also hearing reports that 8131 kHz is supposedly being used by Russian Strategic Bombers for voice communications and it has been very active within the last few hours. The WebSDR linked in the tweet is already at capacity, but you may be able to hear from KiwiSDRs stationed around Europe.

DAB+ Decoder Welle.io Version 2.4 Released and YouTube Demonstration Video

Version 2.4 of the RTL-SDR compatible DAB/DAB+ decoder called welle.io has recently been released for download on GitHub. The main changes include various bug fixes, the addition of Windows 11 support, and the return of the Android APK (but only with rtl_tcp support).

The author has also released a new YouTube video tour, demonstrating the software in action, and explaining all the features.

Showing welle.io a SDR to listen DAB/DAB+.