Category: Amateur Radio

New York Times Story on Intercepted Russian Forces Radio Communications

The New York Times have recently run an incredible video story about how Russian radio communications are being intercepted and recorded by ham radio operators and open source radio monitoring hobbyists in Ukraine. Some of the communications reveal the extent of the logistical issues experienced by the invading forces, and perhaps have even recorded evidence for war crimes.

It appears that much of the invading Russian forces use simple unencrypted analogue voice over HF channels that can be intercepted and recorded by anyone with an HF software defined radio, or anyone willing to monitor nearby web-based SDRs like KiwiSDRs and WebSDRs. In the video screenshots of recordings played back in SDR# and various WebSDRs are displayed.

The story focuses mostly on the audio recordings that highlight communications between Russian forces discussing attack plans, including plans to bombard residential areas with artillery. These recordings are cross-referenced with reports and videos of actual tank sightings and destruction in the areas discussed on the radio.

A later recording highlights communications from a distressed Russian vehicle under attack, requests for air support being unfulfilled, and urgent requests for supplies like fuel, food and water. 

Russia Struggled to Capture a Ukrainian Town. Intercepted Radio Messages Show Why.

Some of the monitoring projects involved are highlighted in the story and they include, Project Owl, Ukrainian Radio Watchers, ShadowBreak and NSRIC (Number Stations Research and Information Center). We are also aware of at least one other organization attempting to record communications within Ukraine as well that may be making use of RTL-SDRs, HackRFs and other SDRs.

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 

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

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 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 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.

Frugal Radio: Testing a Loop on Ground Antenna with an Airspy HF+ Discovery

The KK5JY Loop on Ground (LoG) antenna is a 15 feet per side square loop designed for reception of HF and lower. It simply consists of an isolation transformer and wire that as the name implies is placed somewhere on the ground in a square loop like shape. It is cheap and easy to build and compact in that it does not take up any usable space. 

In his latest video Rob from the Frugal Radio YouTube channel tests out this antenna with his Airspy HF+ Discovery SDR. He uses a bit of wire lying around, and a low cost 9:1 Balun from NooElec as the isolation transformer. With this antenna he was able to pick up signals in the USA and all the way over to Australia from his home in Canada. NDB signals were also receivable.

2022 LoG (Loop on Ground antenna) for SDR radio tested on Airspy HF+ Discovery SDR KK5JY HAM radio

An APRS Tracker with HackRF, WebUSB and WASM

Thank you to Radoslav Gerganov for writing in and submitting news about the release of his open source web-based APRS tracker named "aprs-sdr". The web based software turns a HackRF device into a mobile APRS beacon.

Most interestingly the software works via the WebUSB interface, which allows for USB devices like a HackRF SDR to connect directly to the software through USB via the Chrome web browser. So no external app or software needs to be downloaded, all you need to do to run the code is open the hosted aprs-sdr page at with a Chrome browser, and connect the HackRF to your device.

Radoslav writes further:

The tracker is using the HTML Geolocation API to fetch the device’s location and WebUSB to talk with the SDR. The code which generates the packets is written in C++ and compiled to WASM. You can find the source at

And now to some results. I have successfully transmitted packets from my home to LZ0DOE (15km away!) using my Pixel phone, HackRF and ANT500. I find it amazing given the low TX power of HackRF.

Radoslav also notes that in the future he hopes to add other SDRs as well. He also notes that the script seems to work best on desktop Chrome. On mobile Chrome there may be a bug which stops transmission after a few packets.

Using the aprs-sdr WebUSB application.

TechMinds: Testing the GA-450 Portable HF Active Loop Antenna

Over on the Techminds YouTube channel, Matt has uploaded his latest video which is a review of the GA-450 portable HF active loop antenna. The antenna costs between US$60-$80 + shipping and is available on Chinese market sites like Aliexpress and Banggood. It's advertised as covering 2.3 - 30 MHz, and uses a very portable and sturdy 20cm stainless steel loop. The active base amplifier is powered via a USB-C connector, and it even has a built in lithium battery for portable field use.

In his review Matt shows the antenna in action, noting that it's performance is quite a lot better than expected for it's small size, but it can't compare to his large half-wave end fed antenna. He notes that it appears to work best from 7 - 21 MHz, but not so well below 7 MHz. Overall he recommends it if you're looking for a small sized loop antenna.

GA-450 Portable Active Small Loop HF Antenna

Nils Critiques the MH370 WSPR Aircraft Scatter Theory

For some time now there has been chatter about the possibility of using WSPR logs to help track the mysterious disappearance of flight MH370. WSPR or the "Weak Signal Propagation Reporter" is a protocol typically used on the HF bands by amateur radio operators. The properties of the protocol allow WSPR signals to be received almost globally despite using low transmit power.  Amateur radio operators use it for making contacts, or for checking HF radio propagation conditions. MH370 is a flight that infamously vanished without a trace back in 2014.

The theory proposed by aerospace engineer Richard Godfrey is to use logs of sent and received WSPR transmissions that may have intersected the potential flight path of MH370, and to look for potential reflections or 'scatter' in the signal from the metal aircraft hull. From the reflections an approximate track of the aircraft could be calculated much in the same way that bistatic over the horizon radar systems work.

While it is an exciting theory, it is unfortunately considered by most experts as highly unlikely to yield any suitable results with the main problems being WSPR transmission power too weak to detect reflections from an aircraft, and the effect of the ionosphere too difficult to account for. 

Over on his blog Nils Schiffhauer (DK8OK) has posted a thorough critique of the idea, explaining the theory, technical details and difficulties in depth, ultimately coming to the conclusion that the idea is based more in wishful thinking than in fact. Nils summarizes:

Time and again, there are news stories in the professional and popular press about the fact that log data from the WSPR data network can help locate aircraft. In particular, the effort is to determine the actual crash site of flight MH370. This effort essentially amounts to detecting "unusual" level jumps and frequency changes ("drift") in the archived WSPR log data and attributing them to reflections from specific aircraft ("aircraft scatter").

In a blog entry, Nils Schiffhauer, DK8OK, for the first time critically evaluates this theory. On the one hand, this is based on years of observation of aircraft scatter on shortwave as well as an investigation of about 30 Doppler tracks. The results of this complex analysis of more than 10,000 data in one example alone are sobering: The effects of aircraft scatter on the overall signal are almost always well below 0.3 dB.

To prove a correlation between level changes of the overall signal and aircraft scatter seems hardly possible on the basis of the WSPR data material. The reasons are manifold, but lie mainly in shortwave propagation, where level changes of 30 dB within a few seconds are the rule rather than the exception.

However, since the local and temporal state of the ionosphere is not known in previous investigations on the WSPR data material - it is recorded in parallel in professional OTH radar systems and calculated out of the received signal - level jumps can hardly be clearly assigned from the sum signal alone. This finding is supported by further arguments in the blog:

Nils demonstrates aircraft scatter on China Radio International, a 500kW transmitter.

SDRAngel Features Overview: ADS-B, APT, DVB-S, DAB+, AIS, VOR, APRS, and many more built-in apps

SDRAngel is a general purpose software defined radio program that is compatible with most SDRs including the RTL-SDR. We've posted about it several times before on the blog, however we did not realize how much progress has occurred with developing various built in plugins and decoders for it.

Thanks to Jon for writing in and sharing with us a demonstration video that the SDRAngel team have released on their YouTube channel. From the video we can see that SDRAngel now comes stock with a whole host of built in decoders and apps for various radio applications making it close to an all-in-one SDR platform. The built in applications include:

  • ADS-B Decoder: Decodes aircraft ADS-B data and plots aircraft positions on a map
  • NOAA APT Decoder: Decodes NOAA weather satellite images (in black and white only)
  • DVB-S: Decodes and plays Digital TV DVB-S and DVB-S2 video
  • AIS: Decodes marine AIS data and plots vessel positions on a map
  • VOR: Decodes VOR aircraft navigational beacons, and plots bearing lines on a map, allowing you to determine your receivers position.
  • DAB+: Decodes and plays DAB digital audio signals
  • Radio Astronomy Hydrogen Line: With an appropriate radio telescope connected to the SDR, integrates and displays the Hydrogen Line FFT with various settings, and a map of the galaxy showing where your dish is pointing. Can also control a dish rotator.
  • Radio Astronomy Solar Observations: Similar to the Hydrogen line app, allows you to make solar measurements.
  • Broadcast FM: Decoding and playback. Includes RDS decoding.
  • Noise Figure Measurements: Together with a noise source you can measure the noise figure of a SDR.
  • Airband Voice: Receive multiple Airband channels simultaneously
  • Graves Radar Tracker: For Europeans, track a satellite and watch for reflections in the spectrum from the French Graves space radar. 
  • Radio Clocks: Receive and decode accurate time from radio clocks such as MSF, DCF77, TDF and WWVB.
  • APRS: Decode APRS data, and plot APRS locations and moving APRS enabled vehicles on a map with speed plot.
  • Pagers: Decode POCSAG pagers
  • APRS/AX.25 Satellite: Decode APRS messages from the ISS and NO-84 satellites, via the built in decoder and satellite tracker.
  • Channel Analyzer: Analyze signals in the frequency and time domains
  • QSO Digital and Analog Voice: Decode digital and analog voice. Digital voice handled by the built in DSD demodulator, and includes DMR, dPMR and D-Star.
  • Beacons: Monitor propagation via amateur radio beacons, and plot them on a map.

We note that the video doesn't show the following additional features such as an analog TV decoder, the SDRAngel "ChirpChat" text mode, a FreeDV decoder and several other features.

Improving Reception on the Malachite DSP via USB Grounding

Thank you to Mitsonobu Saitou for writing in and sharing with us a product that he has created which improves reception on of the Malachite DSP software defined radio and other shortwave radios by up to 20dB by improving the grounding. It appears to work by using the negative USB line as a ground via a modified USB cable with grounding clip on the other end. The product is available via Amazon Japan with international shipping.

The Malachite DSP is a portable battery powered software defined radio with built in screen. It is popular amongst shortwave listeners.

Saitou writes the following summary, and full details about the product are available on his blog (link uses Google Translate to translate from Japanese to English): 

Today's item is "Dokodemo Earth KUN". This is an item to pull the ground wire from the charging connector of DCL radios and Mlachite DSPs.

The sensitivity of the receiver will be improved by strengthening the grounding. This is how I applied it.

It is easy to connect by pulling out the ground wire from the charging connector instead of the antenna jack.

It can also be used as a loop antenna by connecting the ground to the antenna.

We have confirmed the effectiveness of this product outdoors. Users who have used this item have experienced a significant increase in sensitivity. 

Malachite DSP and SWL Radio USB Grounding Enhancement Cable
Malahit/Malachite DSP+「どこでもアースくん」