Category: Satellite

Lon.TV Demonstrates Decoding Various Digital Signals with RTL-SDR

Tech YouTuber Lon.TV has recently uploaded a video demonstrating how to identify and decode various digital transmissions with an RTL-SDR dongle. In the video he explains how to use VB Cable to pipe audio from SDR# into various decoders, and then goes on to show DMR, APRS, POCSAG, L-Band AERO, FT8, and JS8/JS8CALL all being decoded via an RTL-SDR Blog V3 dongle.

Software Defined Radio Part 2 - Decoding Digital Transmissions with an RTL-SDR USB Radio

SDR# and other Hobbyist Ham Radio Software Spotted in Netflix TV Show Yakamoz S-245

Thanks to all who submitted, we recently received some interesting tip offs about the Netflix TV Show Yakamoz S-245 featuring a scene with various hobbyist SDR and ham radio programs clearly visible. Yakamoz S-245 is a show about a submarine research mission, and the scene appears to depict military intelligence specialists using the programs.

In the scene we've spotted SDR#, MMSSTV, FUNcube dashboard, SATPC-32, and Orbitron. For those interested, the scene is in episode one time 11:20 - 12:00. 

Receiving Analog TV from Turkmenistan Unintentionally Bouncing off a Russian Military Satellite

Over on Twitter @dereksgc has been monitoring the 'Meridian' communications satellites, which are Russian owned and used for civilian and military purposes. The satellites are simple unsecure repeaters, meaning that actually anyone with the hardware can transmit to them, and have their signal automatically rebroadcast over a wide area. This has been taken advantage of recently by anti-Russian invasion war activists who have been trolling the satellite with SSTV images of the Ukrainian flag, as well as audio.  

Apart from intentional abuse, a side effect of being an open repeater is that sometimes the satellite can pick up powerful terrestrial signals unintentionally, such as analogue broadcast TV from Turkmenistan. Over on his blog, @dereksgc has written up an excellent post documenting the background behind this finding, his entire setup involving the hardware he's using and how he's aligning with the satellite, and what software he is using to decode the TV signal. In his hardware setup he notes that he uses a HackRF, but that a RTL-SDR would suffice.

Mapping GPS/GNSS Interference Through ADS-B Data

Websites like adsbexchange.com log ADS-B aircraft tracking data from contributors located all over the world and aggregate it all onto a single map. Typically an RTL-SDR is the receiver of choice for contributors receiving ADS-B signals. One piece of data that is recorded with each packet is GPS/GNSS accuracy.

Over on Twitter John Wiseman @lemonodor has been using the aggregated ADS-B data provided by adsbexchange to highlight regions where ADS-B GPS inaccuracies are significant. This may allow us to use crowd sourced data to detect regions of GPS interference or jamming. In one of his latest findings he noted extreme GPS inaccuracy that noticed around the Baltic regions (Poland, Lithuania, Latvia, Kaliningrad).

As John and others reported in subsequent Tweets, this GPS interference was noticed by others too, with some flights needing to be cancelled or needing to return during their journey, and a NOTAM warning being issued to pilots regarding the interference. Reuters also reported on the GPS disturbance a few days later.

NOTAM: GPS INTERFERENCE DETECTED IN THE EASTERN PARTS OF HELSINKI FIR. AFFECTED AREA SECTOR N, SFC-FL200

It is well known that Russia routinely utilizes GPS spoofing or jamming around Kremlin landmarks, sensitive areas and during military operations. However, others noted that NATO exercises in the Baltic could also be the cause.

To further add to this story, the satellite intelligence operator Hawkeye 360 also recently detected significant GPS interference within or around Ukraine.

Hawkeye360 Detects GPS Interference near or within Ukraine.

Receiving NOAA Global Area Cover (GAC) Images with LeanHRPT

A few weeks ago we posted about how @ZSztanga and @aang254 were able to record and decode Global Area Cover (GAC) images from polar orbiting NOAA weather satellites. GAC images are low resolution, but they provide an image of the entire orbit. The GAC signal is only transmitted over the USA.

A week earlier than @ZSztanga and @aang254 above decoded GAC, another software called LeanHRPT by @Xerbo also implemented a GAC decoder. LeanHRPT is available on Windows, Linux and MacOS, and ready to download binaries are available on the releases page. You'll need the LeanHRPT demodulator too, in order to initially demodulate the signal.

@Xerbo also notes that @dereksgc has also released a useful Python script for predicting NOAA GAC transmissions. It shows when a particular NOAA satellite will begin and end their GAC transmission, as well as the frequency, polarization and elevation of the satellite. 

GAC Transmission Prediction Tool

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.

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.

Global Area Coverage (GAC) Images Decoded from NOAA Satellites

Thank you to @ZSztanga and @aang254 for submitting news about their recent success at decoding the L-Band Global Area Coverage (GAC) signal from polar orbiting NOAA satellites. GAC images are low resolution, and described by NOAA as follows:

Global Area Coverage (GAC) data set is reduced resolution image data that is processed onboard the satellite taking only one line out of every three and averaging every four of five adjacent samples along the scan line.

While it's low resolution, the interesting thing about this data is that you get an image of the entire orbit, not just the data from your current location as you'd receive with the standard 137 MHz APT or L-Band HRPT signal. The catch is that the signal is usually only transmitted over the USA, and you'll need a motorized or hand tracked L-Band satellite dish setup to receive it.

We note that GAC data is not to be confused with the Direct Sounding Broadcast (DSB) signal decoding software we posted about in 2020. 

@ZSztanga has provided some more information about what images are available and who can receive it, and @aang254's tweet below provides some images and additional information:

With @aang254 we decoded GAC from NOAA satellites. It's basically a dump of reduced resolution data from the whole orbit. It includes all the instruments and is transmitted on L-band along with HRPT (mostly over USA, rarely above Europe and only NOAA-19 dumps outside the US). All the decoders are in SatDump.

There is also a schedule available (https://noaasis.noaa.gov/cemscs/polrschd.txt) that includes all the dumps in the upcoming week. It might be a bit hard to interpret, but basically there is a date and the ground station name (SVL stands for Svalbard and it is the only one receivable in Europe). Entries with "GAC" or "PBK" are referring to the GAC transmission.

We've also seen a tweet by @OK9UWU that shows a much longer image of a full orbit.