Category Archives: Utility_DX

SDR Console V3: New and indispensable Software


“Living Sonagram”: On the right window, you see a part of a 24 h recording at 6,1 MHz bandwidth (ca. 2 TB) with 1 line/second. Tagged is the sign on of Dimtsi Hafash which is received by the undocked “Receive” panel of V3’s GUI. At the bottom: signal strength on 7180 kHz over 24 hours reveals e.g. s/on, s/off and fade in.

Just a small note on a real real big event: Simon Brown, G4ELI, has published V3 of his indispensable SDR Console software on June 18th, 2018 – after three and a half years of heavy coding. Download it here and donate. Or vice versa.

V3 is a quite universal software for most SDRs on the market. For all, it provides the same graphical user interface (GUI) and the same functions (plus those specific to some devices).


DXer’s delight: On top the sonagram to visually catch signals (here: JDG from Diego Garcia; tagged). Bottom, from left to right: receive GUI for fine tuning, decoder W-Code showing “JDG”, below this “Playback” panel for controlling the recording (back/forward, e.g.), and on the right a database.

There are many unique functions and modules which will take DXing with SDRs to the next step. For now, let me mention just two of them:

  • 24 parallel demodulators within the SDR’s bandwidth – fully independent in e.g. mode, bandwidth and AGC to receive, record and decode 24 signals/channels in parallel.
  • a sophisticated File Analyser  which presents a recorded band as “living sonagram” – whre you see and click to a signal which then is played via the basic GUI

Up to six parallel demodulators can be seen on the main screen (from up to 24 possible).



1520 kHz from 18:00 to 05:00 UTC (local SR/SS: 19:43/02:58 UTC) with 100 Hz bandwidth and 0,0031 Hz resolution (= +65 dB over 10 kHz!) reveals at least 27 stations and their offsets.

Each of these just two features mentioned will open new worlds for DXing and even serious professional monitoring. I will be happy to come back to some applications of V3 in more detail.

Thank you very much, Simon, for providing this excellent tool for free!


4’800 kHz: First CNR1 with sign on at 20:15 UTC and fade out, then AIR Hyderabad with the same, but s/on around 00:06 UTC.



You may export levels over time on one frequency or level over frequencies at a given time. This graph visualizes the activity on 7435 kHz with 86’400 levels (on per second over 24 h). The data had been exported to QtiPlot for further investigation.

INMARSAT: Decoding 12 Aero-channels in parallel


Action: Free software allows for decoding twelve INMARSAT in parallel

A recent post in Carl’s rtl-sdr-blog informed about the ebay-lability of some surplus Outernet patch antennas for just – see here. For just 29 US-$, I got this small antenna with integrated SAW filter (1525 – 1559 MHz) plus LNA. A real bait for me to jump over the limit of 30 MHz reception! Soon I fired up my AirSpy R2 receiver, providing the LNA with power supply (Bias-Tee). It worked fine, and I received a whole bunch of excellent signals by this setup.

As I wanted to receive some aircraft information, so I downloaded free JAERO decoder of Jonathan “Jonti” Olds, also from New Zealand. This fine software can be opened in many instances. In combination with the up to 24 decoders of SDR-Console V3 of Simon Brown, this modest setup turned into a multi-channel satellite reception post.


Here 12 decoders had been assigned – one on each INMARSAT channel. You see also quite good SNRs from the Outernet patch antenna.

Next steps worked as usual with the mutli-channel approach:

  • make up 12 channels in SDR-Console and tune each channel to a different signal. Mode must be USB, and as bandwidth I choose 1200 Hz for 600 bps and 2400 Hz for 1200 bps channels. That’s a bit wider than necessary, but doing so there is some room for the AFC in JAERO decoder always to stick to the signal even if the SDR should drift a bit over 24 h or so
  • The output of each channel is then routed to a different Virtual Audio Cable, or VAC 1-12.
  • Then you have to install twelve instances of JAERO software in different folders, e.g. JAERO 1-12. You should name each JAERO.exe file accordingly, e.g. JAERO_1.exe to JAERO12.exe.
  • Open JAERO_1.exe, assign its input to VAC 1, and set the matching speed of the signal. If all is ok, you will be rewarded by a sharp phase constellation, and soon decoding will start.
  • Repeat the above steps until you have reached JAERO_12.exe, connected to VAC 12.

The “Matrix” of SDR-Console V3 shows the twelve channels with different signal strengths and width, depending on the data rate (600bps/narrow, 1200bps/wide).

The result can bee seen from the screenshot at the top of this page. The whole setup ran stable and unattended for hours.

Thanks for all smart people having developed the smart software and hardware!

SDR-Netz des DARC e.V.: Rauschende Ergebnisse


Einfach vergleichen: Oben CHU 14.670 kHz an einem Remote-Standort des DARC e.V., unten zur selben Zeit an einem durchschnittlichen Standort.

Aus den Mitteln seiner “Mitgliedschaft Pro” bestellte der DARC e.V. im Jahre 2014 sein Web-SDR-Transceivernetz. Es soll seinen Mitgliedern “weltweiten Funkbetrieb aus dem heimischen Shack ermöglichen”. Jeder der über 1.000 DARC-Ortsvereine war aufgerufen, sich als einer der zwölf Standorte zu bewerben. Gesucht waren solche Locations, die vor allem einen störungsarmen Empfang und gute Antennenmöglichkeiten bieten – was der Funkamateur in der Stadt eben nicht hat.

Obwohl die R2T2 genannten Geräte für über 25.000 Euro längst ausgeliefert wurden, ist es bedauerlicherweise merkwürdig still um dieses schöne Projekt geworden; auch die zugehörige Yahoo-Newsgroup scheint nicht mehr ansprechbar zu sein.

Wie also ist der von außen (ich bin kein Mitglied des DARC e.V., begrüße aber dieses Vorhaben uneingeschränkt!) sichtbare Stand des Projektes?

Um das zu erkunden, habe ich am 20.12.2017 alle verfügbaren Remote-Standorte (sechs, und die auch lediglich empfangsseitg ansprechbar) mit dem Empfang “im heimischen Shack” – leider einer ziemlich durchschnittlichen Location – verglichen.

Die ersten Ergebnisse habe ich in einem PDF zusammengefasst, das ihr hier unter R2T2 herunterladen könnt.

Diese Versuche wurden zur Vervollständigung des Bildes fortgesetzt – siehe unten. So nahm ich am  21.12. um 07:45 UTC einen Vergleich auf 17.950 kHz vor, wo bei mir der Rundfunksender China Radio International/Kashgar mit einem SNR von gut 31 dB einfiel: bis auf ein sehr schwaches und praktisch unverständliches Signal vom Remote-Standort Wiblishauserhof war auf den anderen Remote-SDRs des DARC so gut wie nichts zu hören, zum Teil wegen (lokaler?) Störungen. Unten der Vergleich meiner Station (unten)  mit dem bayerischen Remote-SDR (oben).


Vergleich China Radio International, 17.950 kHz: oben der bayerische SDR des DARC-Remote-Netzes, unten dieselbe Station zur selben Zeit am Standort DK8OK.

Einen weiteren Test unternahm ich am 26.12.2017 gegen 12:30 UTC auf 1.521 kHz (CRI/Kashgar, Nähe zum 160-m-Band) und auf 4.800 kHz (China National Radio 1/Golmud). Diesmal erfolgte der Vergleich an einer Aktivantenne (statt der Quadloop)  meinerseits, die bei beiden Stationen eine Empfangsqualität von SIO 253 bot.
In beiden Fällen war das Ergebnis ähnlich: von den sechs verfügbaren Remote-SDRs konnte drei die Stationen überhaupt nicht empfangen. Eine weitere lag knapp über der Hörschwelle, Schöppingen zog fast gleichauf, während Wiblishauserhof in etwa Gleichstand mit meiner Anlage bot – als einzige Station von zwölf bezahlten/geplanten. Für gut drei Jahre Bauzeit und über 25.000 Euro Investment ein Befund mit durchaus Luft nach oben.

Eine Fortsetzung derartiger Vergleiche scheint daher solange sinnlos, wie das DARC-Netz nicht erweitert bzw. Standort/Antennen/SDRs entscheidend geändert werden.

Was hingegen engagierte Hobbyhörer ehrenamtlich und mit allein privatem Geld im Gegensatz zum “Bundesverband für den Amateurfunkdienst” der staatlich geprüften Hobbyfunker zustande bringen, zeigt – ebenfalls mit 14-Bit-SDRs – das leistungsstarke Kiwi-Netz.

Airspy HF+: What you hear, is what you get



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It has been dubbed “game changer” and indeed, the Airspy HF+ is a completely other animal of software-defined radio, or SDR. Developed by Youssef Touil plus team and produced by ITEAD, it sells for just US-$ 199 right from factory at Shenzhen, China. This is considered the middle class of SDRs, starting with cheap USB sticks under 10 US-$ and scratching the mark of nearly US-$ 5.000 with Winradio’s WR-G39DDC. This one also marks the transition zone from what even an engaged hobbyist allows himself to spend to the truly professional receivers of e.g. Rohde & Schwarz and Plath. To make it clear: You may achieve professional results at each price tag, even from an RTL & its clones, as Carl Laufer’s excellent blog shows almost daily.

The Serious HF-DXers in mind

Airspy HF+ has been developed with the serious HF (shortwave) listener in mind. In this field it sets new standards regarding sensitivity, dynamic range and noise. Its stunning performance is achieved by a revolutionary approach and a careful layout of the hardware, housed in a sturdy metal case.

I don’t want to add another explanation of this concept (my test report will appear in 1Q/2018 in “Funkamateur“) but just offering the pure stuff. Some first twelve audio examples should give you a truly hands-on impression to answer the one and only question: How loud does this animal roar?
Therefore, I compared about 100 often vastly different situations on HF between Elad’s FDM-S2 (US-$ 525) and Airspy HF+. From this collection, I carefully selected some first twelve examples to cover the needs of the casual listener as well as the hard-core DXer.

All audio clips were recorded in parallel with a 20 m quad loop as antenna, feeding a professional 1:2 HF splitter by Heros. Software used was free SDR-Console V3 by Simon Brown – thanks.

Dare to make use of your own understanding

First, you read a description of the case, followed by a recording with FSM-S2 and then by Airspy HF+. Each of both examples has been recorded with exactly the same bandwidth, mode, AGC etc. which had been optimized for that situation. You must listen to these audio clips with headphones to scrutinize the mostly very small differences. Aim you ear towards fading, noise and intelligibility.
This is not a traditional test, where the master of ceremonies masticates the results for you. It’s for the truly demanding DXer, “to make use of your own understanding” (Kant, 1784). Just a hint: weak stations make the difference!

Fasten your Headphones: The Examples

The audio examples are roughly sorted from easy to difficult signals. They were made in the first week of December, 2017.

Radio Sultanate of Oman, Seeb/Oman
15.140 kHz, 100 kW, AM, 5.350 km, 14:10 UTC, strong/free channel, SAM, 10 kHz bandwidth. Keep an ear on noise and slight fading!


Xinjiang People Broadcasting Station, ÜrümqiChina
4.500 kHz, 50 kW, AM, 5.500 km, 14:24 UTC, fair to good/free channel, SAM, 9 kHz bandwidth.


Bangla Desh Betar, Savar/Bangladesh
4.750 kHz, 100 kW, AM, 7.300 km, 14:29 UTC, fair/free channel, SAM, 9 kHz bandwidth.


Xizang People’s Broadcasting Station, “Holy Tibet”, Lhasa/China
6.025 kHz, 100 kW, AM, 6.850 km, 16:00 UTC, fair/strong broadcaster 5 kHz up, ECSS-L, 2,8 kHz.


Bangkok VOLMET, Bangkok/Thailand
6.676 kHz, 10 kW, USB, 8.800 km, 16:10 UTC, fair/free channel, USB, 3 kHz bandwidth.


Gander VOLMET, Gander/Newfoundland Canada
10.051 kHz, 10 kW [?], USB, 4.400 km, 15:20 UTC, weak to fair at fade-in/free channel, USB, 2,8 kHz bandwidth.


Myanma Radio, Yangoon/Myanmar
5.985 kHz, 50 kW, AM, 8.250 km, 01:00 UTC, weak to fair/interference from upper channel, ECSS-L, 5,5 kHz bandwidth.


Radio Aparecida, Aparecida/Brazil
6.135 kHz, 10 kW, AM, 9.900 km, 00:30 UTC, fair/free channel, SAM, 3,5 kHz bandwidth.


Time Signal Station CHU, Barrhaven/Ontario Canada
3.330 kHz, 3 kW, USB with carrier, 5.900 km, 06:00 UTC, fair/fsome interference from digital station above, USB, 3 kHz bandwidth.


Time Signal Station BPM, Shaanxi/China
15.000 kHz, 20 kW, AM, 7.750 km, 09:00 UTC, weak/free channel, SAM, 5 kHz bandwidth. Occasionally echo from mixing short/long path, some CW echo (long path) is running into the next via short path.


China Radio International, Ürümqi/China
1.521 kHz, 500 kW, AM, 5.500 km, 13:00 UTC, weak at fade-in/free channel, SAM, 6 kHz bandwidth.


Auckland VOLMET, Auckland/New Zealand
6.679 kHz, 5 kW, USB, 25.800 km (long path!), 07:20 UTC, very weak/free channel, USB, 3,6 kHz bandwidth. Here headphones are a must!



GRAVES: Reflections out of the blue

A GRAVES reflection from a meteor trail, August 21st, 2017 at 10:51 UTC. Received with FDM-S2 from Elad, a discone antenna and software V3 from Simon Brown

Undoubtly, a Graves is a fine French wine from the Bordeaux region in western France. So it is so surprise that also GRAVES is an extraordinary Radar station. It was built to detect and follow satellites and their debris. They sequentially cover from 90° to 270° azimut in five big sectors A to D, and change from sector to sector each 19,2 seconds. Each of this sector is further divided into 6 segments of 7,5° width, covered for 3,2 seconds each.

They are transmitting on 143,050 MHz. If you are in Europe and tune into 143.049,0 kHz USB, you probably will hear/see some reflections of meteors, airplanes and even spacecraft. The distance between the transmitter and my location is about 630 km, and for their southly directed transmissions, there most of the time is no direct reception.

So, if you tune into 143.049,0 kHz, you will see just a blue spectrogram: noise. If you wait for a while, some signals will appear out of this blue; see screenshot on the top. With Simon Brown’s free software Version 3 you may also take a level diagram in smallest time steps of just 50 milliseconds:

A level diagram of the meteor trail reflection from the spectrogram at the top, visualized qith QtiPlot.

This level diagram shows the big advantage of SDRs, working on the signals on HF level, rather than of audio level as with legacy radios. The latter additionally introduce e.g. noise and phase errors. Of course, you may also listen to this signal:

From this audio, in turn, you may do an audio spectrogram, possibly revealing further details of e.g. of the trilling sound like that from a ricocheting bullet: The Searchers (the 1956’er Western film by John Ford, not the British boy group from 1960 …) on VHF.

Audio spectrogram of the sound, revealing “packets” of sound which result in the trilling audio. At start, these packet show a width of about 42 milliseconds to be reduced to 37 milliseconds.

P.S. If you want to donate: my favourite Graves is from Domaine de Chevalier, blanc …

Murmansk FAX: 6.328,5 kHz, new Frequency


Tune into 6330,4 kHz LSB, to get the right black/white frequencies, centered at 1.900 Hz. Shift 1.000 Hz, so 1.400 Hz = white, 2.400 Hz = black. 120 RPM/576 IOC, no APT! Received on June 9th, 2017, at 04:50 UTC.

Reports of the death of Murmansk FAX had been slightly exaggerated … After having searched for it in vain in 1Q/17, it now popped up on 6.328,5 kHz from former 6.445,5 kHz with an irregular schedule, namely at 03:30 UTC at one day and 04:50 UTC another day.

Just fair quality of both, conditions and transmitter, made it very difficult  to read the text in the upper part of this weather chart in Cyrillic, with just: Прогноз … 21 час [Prognosis … 21 hour …]. Receiver AirSPy & SpyVerter, decoder Wavecom W-Code.

Also received on June 1st, 2017, but starting at 03:30 UTC – same area, first half of the transmission heavily distorted by an RTTY signal, see below:


Reception on June 1st, 2017, from 03:30 UTC on 6.328,5 kHz.

Iceberg Prognosis has been received on scheduled 8.444,1 kHz at 20:00 UTC on June 8th, 2017; see below:


Murmansk FAX with Iceberg Prognosis  on 8.444,1 kHz at 20:00 UTC on June 8th, 2017. Cyrillic texts not quite readable. Also received on May, 31st, 2017, same frequency, same time.

Not a trace on/near also listed 7908,8 kHz. It seems that otherwise commendable NOAA publication Worldwide Marine Radiofacsimile Broadcast Schedules is outdated regarding this station.

iZotope RX6 – A Miracle in restoring Audio

If you still desparately looking for a software to restore your recorded DX audio clips, iZotope’s RX6 offers an alomost perfect solution. While the de-crackling tool automatically removes all of these annoying statics, the near-unbelievable tool “Spectral de-noise” is doing wonders in extracting e.g. formants of speech out of noise, thus greatly enhancing intelligibility.

I did a convincing test with a clip of CKZN, New Foundland’s shortwave station still transmitting on 6.170 kHz with 1 kW; received June 1st, 2017 at around 02:00 UTC. The original recording is heard like this:

It looks like this, when opened in RX6, with spectrogram in the background:


First step was to automatically get rid of most of the static by “de-crackling”. RX6 offers you the chance to see also the garbage, e.g. what has been subtracted from the signal, see screenshot below with a focus on the identified crackles:


After this first step, the audio sounds like this:

Second step is the tool “Spectral D-noise”. Most comfortable is the “adpative mode”, where you see the audio much more clearly than in the original recording:


And that’s the way, it sounds, with 12 dB attenuation of noise (default):

Another mode is the “learning mode”, where you teach the software what it has to consider as noise in the recording, and then clean it up. First, I did it with the strongest value of 40 dB reduction:

Sounds quite artifical – but drop your ear onto the last part, how clean the jingle sounds!

With some right, default is 12 dB, listen here:

This may be reduced to even 6 dB – you have to find the right balance by yourself:

To restore audio of DX MP3 clips, is not where this software is really adressed to. But even for this purpose, it’s strong algorithms perform better than any other device/software, I’ve seen in the last 50 years. And there are a lot more functions to tweak a signal further. Not really cheap, but unique. There’s simply nothing better!


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