Magnificient FDM-S3: the Millihertz Magnifier

1340kHz, 25Hz window, resolution bandwidth 0.0061Hz: more than 100 U.S. AM stations are discernable by their frequency offset.Antenna: vertical active dipole MD300DX, 2 x 5m. Visualized with SDRC V3 software by Simon Brown, G4ELI.

With Elad’s FDM-S3 SDR now hitting the market, we have a receiver at hand which is supported by an OCXO/ GNSS frequency reference. This combines short-time accuracy with long-time stability and allows for precise frequency measurement in the millihertz range (under 30MHz). Exploiting this feature is as exciting as it is innovative. With this new tool, also a new kind of DXing is evolving. One example is propagation analysis. See below the 24h spectrogram of Radio Gotel from Jabura/Nigeria on its exclusive channel of 917kHz:

Radio Gotel transmits from 04:00 UTC to 23:00 UTC on 917kHz. In this spectrogram you clearly see sign-on, sign-off; fade-out, fade-in, plus some other feature like two short power breaks in the evening as well as some instabilities.

What surprises, is both, the late fade out at around 07:30UTC and the early fade-in as early as 15:20UTC. It is important to note that you here see the carrier with a resolution bandwidth of 0.0009Hz, roughly just one millihertz. The gain, compared to a listening bandwidth of 10 kHz, is a whopping 70dB, allowing extreme DX. Audio starts to emerge only from around 18:00UTC. As DX Atlas shows, the whole path between my location and Radio Gotel is under daylight at the palpable fade-in at around 15:20UTC, see screenshot below.

At the first visible trace of Radio Gotel at DK8OK’s location on 19JAN2021, with the whole path still is in daylight. Illustration with the help of DX Atlas software.

As with all new things: “We’ve only just begun”, Carpenters, 1970. To be continued.

Prösterchen: DARC-Funktionäre lassen ‘s krachen!

Prioritäten setzen: 2019 erhielt das “Referat HF-Technik” des DARC gerade mal drei Prozent jener Summe, mit der sich die DARC-Funktionäre für ihr Essen & Trinken von den Mitgliedern aushalten ließen – wohl bekomm ‘s!

Seit ich als junger Mensch in den Deutschen Amateur Radio-Club e.v. (DARC) eintrat, höre ich dieselbe Melodie: “Der Altersdurchschnitt unseres Vereins ist zu hoch! Wir müssen zudem mehr Technik machen!” Diese Sprüche haben selbst meinen Rausschmiss im Jahre 1992 überlebt – und doch hat sich geradezu dramatisches getan! Nein, nicht in Sachen Senioren-Überhang, auch nicht in Sachen Technik-Präferenz. Sondern im weiteren Niedergang von rund 60.000 Mitgliedern kurz vor meinem Rausschmiss bis Anfang 2021, wo es noch gerade mal 32.808 Mitglieder sind.

1.000 Mitglieder weniger je Jahr

Im Zusammenhang mit meinem Rausschmiss hatte ich die Funktionäre gewarnt, dass wegen dieser ausgepichten Art des Ham Spirit sicherlich ein paar Mitglieder den Verein verlassen würden. “Wie viele, meinst Du denn”, fragte jemand höhnisch zurück. Darauf ich: “So um die 1.000 Leute, etwa!”, und, in sein darob berstendes Lachen hinein: “Nicht insgesamt, sondern Jahr für Jahr 1.000 Leute.” Die Herren Funktionäre lachten Tränen. Nun, nach 27 Jahren, hat der DARC gut 27.000 Mitglieder weniger als zu jenem Zeitpunkt. Wer einen Dreisatz beherrscht, kann sich ausrechnen, dass meine Einschätzung halbwegs realistisch war – und die Funktionäre ihre Hanswurstereien betrieben.

Soweit, so schlecht. Aber feiern, das verstehen die Herren (und wenigen Damen) DARC-Funktionäre vorzüglich: knapp 57.000 Euro gaben sie für Essen & Trinken allein im Jahre 2019 aus: Prösterchen! Und die Jugend? Bei einem Beitrag von 31,20 Euro im selben Jahre für unter 18-Jährige mussten über 1.800 dieser Jugendlichen ihre kompletten DARC-Mitgliedsbeiträge aufwenden, um den Appetit & Durst der Funktionäre angemessen zu stillen.

Referat HF-Technik: drei Prozent der Bewirtungskosten

Aber – Technik genießt doch bei unserem technisch-wissenschaftlichen Hobby den Vorrang vor allem anderen? Follow the money: 1.842,30 Euro erhielt das “Referat HF-Technik” – die Herzkammer des Vereins – für ihre Tätigkeit. Dem Taschengeldempfänger oder dem Kleinrentner mag das angängig dünken. Doch es sind nur drei Prozent der sogenannten “Bewirtungskosten”!

Das aber ist noch lange nicht das Ende der Wohltaten. Denn für genau 10.740,63 Euro machte man “Geschenke”. Vermutlich mehr unter seinesgleichen, als dass man Jugendliche damit beglückte.

Aber die Reiselust, die ist doch bei einem Verein, in dessen Zentrum die technisch-schwere-, wie kostenlose Kommunikation steht, kein Thema, oder? Nicht ganz. Denn wiederum im Jahre 2019 finanzierten die Mitglieder 200.744,18 Euro an Reisekosten für ihre Funktionäre: “Lebe wohl, gute Reise” (Comedian Harmonists, 1934). Bei der Rechnungslegung für 2020 wird man hoffentlich sehen, welcher Anteil davon überflüssig war.

Die Kosten der vielen sind Einnahmen weniger

Doch des einen Kosten, sind des anderen Einnahmen. Seit dem Jahre 1340, als man den schönen Buchungssatz “Soll an Haben”, wohl in Genua, erfand. Nein, hier soll nicht die Rede von den angeblich rund 150.000 Euro sein, die ein Vereinskamerad ohne jede Ausschreibung für die Übersetzung eines Buches erhalten haben soll, das man seitdem vor praktisch aller Welt versteckt und das nach DARC-eigenen Maßstäben mit gerade mal rund 10 Prozent dieser Summe entlohnt worden wäre. (Dieser Fall dürfte im gesamten deutschen Verlagswesen einmalig sein. Jeder Verlagsgeschäftsführer wäre fristlos geflogen, hier aber scheint der damalige 1. DARC-Vorsitzende die Sache abgesegnet zu haben – anders ist es nicht denkbar.)

Aber bleiben wir weiter bei den Einnahmen, die ja die Kosten der Mitglieder sind. Für Rechts- und Beratungskosten kassierten Rechtsanwälte und Berater 85,475,77 Euro im Jahre 2019, wozu sich noch 5.422,99 Euro “Rechtskosten” addierten. Wie man inzwischen weiß, ist dieses Geld auch dafür ausgegeben worden, um unbotmäßige Mitglieder mit kostenträchtigen Schreiben zu zwiebeln. Von rechtlichen Durchbrüchen bei Antennengenehmigungen oder in Sachen EMV hat man hingegen nichts gehört.

Notfunk in Not

Und wie steht es um den Notfunk, der neben Jugendarbeit und Technik als heilige Dreifaltigkeit immer dann ins Schaufenster gestellt wird, wenn man die gesellschaftliche Wichtigkeit des Amateurfunks darstellen will? Macht keine 1,6 Prozent dessen, was der DARC für Rechtshändel & Co. ausgibt.

Dick loben aber wollen wir doch die 27,20 Euro, die der DARC 2019 für das UKW-Funksport-Referat springen ließ (also nicht einmal das Trinkgeld in einem Sterne-Schuppen). Denn Funksport ist ja auch wichtig! Gegenüber den Ausgaben für das, was die Funktionäre “Referat Handicap Hams” nennen, erscheint das absolut top generös – denn der Etat, mit dem der DARC unser Hobby für Menschen mit Beeinträchtigungen fördert, liegt bei exakt 0,00 Euro. “Gemeinnützigkeit” will halt verdient werden.

Nur kein Neid!

Zur Klarstellung: Ich esse, trinke und reise selbst ebenso gerne wie gut. Allerdings, Essen & Trinken, auch in der Drei-Sterne-Gastronomie, als Alleinzahler. Zu Neid besteht bei mir kein Anlass, in das DARC-eigene “Hotel Stadt Baunatal”, allerdings hat mich selbst meine sonst unstillbare Neugier noch nicht geführt. Aufmerksam machen wollte ich hier lediglich auf etwas, was man als Missverhältnis zwischen Reden und Tun auffassen kann, zwischen Dampfplauderei und den harten Fakten einer Bilanz. Damit sich was ändert. Am besten, zum besseren.

Wer die Verantwortung trägt

Die Bilanz, übrigens, sollten die Rechnungsprüfer (Kosten “Rechnungsprüfungsausschuss”: 1.016,62 Euro) nicht nur dahingehend prüfen, ob 1 und 1 richtig zusammengezählt sind, sondern auch, ob das Geld entsprechend des Vereinszwecks ausgegeben wird. Und der lautet beim DARC immer noch nicht: Essen Trinken, Reisen. Nicht zuletzt hat der Amateurrat es in der Hand, dem Finanzgebaren (von dem er allerdings unmittelbar ebenso wie mittelbar profitiert) zuzustimmen oder zu widersprechen. Und? Angenommen bei 67 Ja-Stimmen, keiner Gegenstimme sowie zwei Enthaltungen. Wenn einem so viel Gutes widerfährt, das ist schon einen Asbach Uralt wert, wie es erstmals 1955 hieß – wir sprachen ja über das Thema “Überalterung”. Vielleicht gar einen “Asbach Goethe” – ein Rollgriff ins Spesenkonto würde das lässig hergeben.

Seeing is believing: Tableau visualizing MWLIST

All medium wave stations from MWLIST, drawn with free Tableau software: the size of the circles represents the power of the stations, the colour the type of network.

Broadcasting on medium wave still is a very active part of using the electromagnetic spectrum. An unique and outstanding source of information is supplied for free by MWLIST, a team of smart DXers. They provide tons of up-to-date and precise information – down to exact locations and even offsets from the nominal channel.

By visualizing those data, you get an even better insight. Here, free Tableau Public software is (for me) the tool of choice to do just that – please see the screenshot on top of this page. You simply download the free Tableau app, and – also for free – sign up, and you are done.

For me, most striking is visualizing the spatial data, i.e. to show the transmitters at their proper place on a map. Another welcome feature is filtering the data to answer specific questions like: How are traffic broadcast stations above 1.6 MHz spread over Pennsylvania? Or: What can I expect listening on 1521kHz on a late winter afternoon in Europe? Or: Where are Chinese stations located, carrying the CNR1 programme of China National Radio? You will find screenshots illustrating these examples below.

Those are just screenshots, not active maps. If you want active maps, there is an option (WP-TAB, Tableau Public Viz Block) available for WordPress’ business version which I don’t have at hand.
But there is a simple solution: go to my Tableau Public page, download my TWBX-map “Medium Wave Station [Copyright MW List]”, and it will automatically be loaded into your Tableau Public app – after you have installed this. Then the map comes into live, and you can do all filtering, zooming etc.

[My profile photo shows a fisher’s deity in Japan, seen in October 2019 in Tokyo’s Kappabashi street. As a DXer and hobby cook, I thought location and statue being quite appropriate – thanks for asking …]

Surely, you immediately will find other ideas to realize, e.g. marking heard/verified signals by just a flag in your list and combining this with a special color on that station on your Tableau map.

Kiashahr broadcasting center of IRIB, the Iranian broadcaster, on the shores of the Caspian Sea. All three antenna sites are pinpointed on Tableau’s “Satellite” background map. Listen to the recording of IRIB Gilan (from the antennas at the left) below:
IRIB Radio Gilan, received on December 30, 2020 at 14:30 UTC in Germany.
Traffic broadcast in Pennsylvania duly follows the trail like pearls on a string, here e.g. US Highway 80 in the mid of the screenshot.
1521 kHz on a winter afternoon in Europe: What stations can be expected, and what interference should be avoided? MWLIST’s spatial data plus Tableau’s power of filtering the data and drawing it onto a map will show this at a glance.
How are transmitter, carrying the CNR1 programme, scattered over China? This screenshot will tell.

P.S.: Taking some suggestions from the fruitful discussion which follows the initial publication of this site, I like to add some more examples:

If you are looking for some challenges, a European listener may start with low-power stations in the UK (LPAM), transmitting with just 1 Watt of power, leaving 500mW from both sidebands, combined, for the audio at max. Filtering the MWLIST with Tableau Public and visualizing this by a map, leads to the screenshot below. I also attached an audio clip of Carillon Radio. Yes, reception quality of this station of the Leicester/Loughborough hospital resembles a bit the state of NHS 😉

All LAPM stations in the AM band do transmit with 1 watt of power only. They place a nice challenge for European listeners …
LPAM Carillon Radio on 1386kHz/1W, received on December 27, 2020 near Hanover/Northern Germany. Antenna: MD300DX active vertical dipole, receiver: Winradio Sigma.

A second example is even more challenging for European DXers, but not entirely impossible. The map shows some low-power Japanese service radio stations for parks, traffic, weather and harbours.

MWLIST has been filtered, so that Tableau’s map shows just the low-power Japanese service radio stations in the x-band (i.e. above 1602kHz. Reception of those stations in Europe is challenging, but possible, as …
… this recording of Tokyo Martis Radio [highlighted on the map above] on October 23, 2019 on 1663.5kHz shows at 10:00 UTC. The audio clip was extracted by DK8OK from a HF recording [WAV] at Norway’s KONG station, with sincere thanks to Bjarne Mjelde.

RX-888: 32 MHz/16bit, 200 US-$ – pricks up your ears

The RX-888 covers 32MHz @16Bit in a row. Here it comes to life with Simon Brown’s unique and indispensable software SDRC V3 at an professional active dipole antenna MD300DX.

It is the (a few weeks) younger brother to the RX-666, a brainchild of Oscar Steila, IK1XPV. And it is one of the first palm-sized SDRs in the price class of 200 US-$ which covers the whole HF band for receiving, recording and playing with 16Bit resolution, resulting in a competitive dynamic range of about 100dB. I got one from China via eBay (there are numerous sellers) within a few days. Overnight, Simon, G4ELI, made his SDRC V3 software to match also to the RX-888 with excellence. You need a PC, an i5 should do it, with USB3.0 for data streaming, controlling and power supply. Yes, there is no need for a separate 5 or 12VDC!

Much had been speculated about one obvious fact: the price of the A/D chip is, if only a medium order is placed, the same or even higher than the price tag at the RX-888. How comes? One rumor with some substantial background results in this story: the chips had been desoldered from boards of other projects which didn’t pass the quality control. These boards had been sold at a low price as a bonanza to smart people who can use all the parts which on their own will have passed the quality control, most notably the pivotal A/D chip.

This blog should give you a first impression. The biggest difference between RX-666 and RX-888 seems to be that the latter is equipped with a permanent low-noise amplifier of +20dB which perfectly balances sensitivity and dynamic range for 90% of us DXers. Sensitivity on HF is nearly on par with FDM-S2.

Two antenna sockets – the impressive cooling fins on three sides of the box will be needed after a planned update of covering 64 MHz in a row with 16Bit, and up to 10MHz (now: 8MHz) above 64MHz.

I tested the RX-888 from 10kHz to 32MHz and had a look above 32MHz – see the two following screenshots.

RJH69 on VLF 25.0kHz. This time signal from Belarus was received at 07:06 UTC on 02SEP2020 in Northern Germany and read with CW decoder MRP40.
A look onto 8MHz of the FM broadcast band.

The RX-888 also worky nicely together with decoders like DRM or (other) data, see the two following screenshots.

The very weak DRM signal of China National Radio on 9655kHz [Urumqui, 30kW, antenna direction 98°!] is duly received by the RX-888 with the data decoded with free DREAM software.
US Air Force Diego Garcia [JDG] in the Indian Ocean calling their Lajes counterpart [PLA] in the Açores on 4721kHz at 17:18UTC in MIL-STD-188-141A.

PC power: Nowadays, a “receiver” is a system, consisting of an SDR (the box), software and the PC. While world-class software SDRC V3 is for free, and an top SDR costs just about 200 US-$, you should not forget an able PC. It must be an i5 and up if you want to digest bigger bandwidth like 8 MHz, 16 MHz or even 32MHz. Even for recording 32 MHz, there is no need for internal SSDs, a fast iron disk will do the job. Furthermore: 32MHz recording for 24 hours do expect a bit more than 11TB disk space. This calls for an external HD, and a second USB3.0 card (not: hub!) is a must. As external HD, I use the WD MyBook Duo, delivering 28TB at under 750 US-$. The combination of an desktop i7 and this HD ensures stutter-free recording and playing up to bandwidth of at least 32MHz. Here simply more is more …

Last, but not least, please find below a few audio examples of broadcast as well as utility stations. They proof that the RX-888 is a serious receiver at a ridiculous low price.

4712 kHz/USB: Russian Airports with radio checks in Russian: Kazan, Rostov (net control), Saratov, Samara, Novosibirsk, Chelayabinsk. They transmit with 1kW of power to a low-hanging dipole. 02SEP2020, 17:00 UTC.
4750kHz/AM-ECSS: Bangladesh Betar with ID over an obviously defective transmitter (nominal 100kW). 02SEP2020, 17:00UTC.
4800kHz/AM-SAM: Chinese National Radio Beijing I (Geermu, 100kW) ID in Mandarin, ID. 02SEP2020, 22:00 UTC.
4920kHz/AM: Tibet People’s Broadcasting Station (Lhasa, 100kW), ID in Tibetan. 02SEP2020, 21:00 UTC.
5000kHz/CW: Chinese Time Signal Station BPM (Sha’anxi/Pucheng, 5kW), ID in CW. 02SEP2020, 22:00UTC.
6676kHz/USB: Singapore VOLMET, 5kW, ID and weather in English. 02SEP2020, 17:20UTC.
6676kHz/USB: Bangkok VOLMET, 5kW, ID and weather in English. 02SEP2020, 18:10UTC.
7240kHz/AM: Tibet People’s Broadcasting Station (Lhasa, 100kW), ID in Mandarin. 02SEP2020, 21:00 UTC.
9275kHz/AM: FEBC Philippines/Bocaue (100kW), ID in Mandarin. 02SEP2020, 14:00 UTC.
9310kHz/AM: VoA Deewa Radio (Udon Thani/Thailand, 250kHz), ID in Pashtun/Urdu. 02SEP2020, 14:00UTC.
9664,77kHz/LSB: Radio Voz Missionaria (Camboriu/Brazil, 10kW), ID in Portuguese. 02SEP2020, 22:00UTC.
10’000kHz/CW: Chinese Time Signal Station BPM (Sha’anxi/Pucheng, 5kW), ID in CW. 02SEP2020, 17:00UTC.

RX-888: 32 MHz, 16 bit – A new standard SDR for HF

A bare sensation: the RX-888 covers 9 kHz to 32 MHz with 16 bit (nearly 100 dB dynamic range) with recording and playing the whole range via USB3.0 which also cares for the power supply. Price: just about 200 US-$.

With the RX-888 just has arrived here, I am busy with testing. The first results a very much encouraging with Simon Brown’s (G4ELI) unique software SDRC V3. More to come within a few days.

Switching-on HF Transmitters: Step by step

Voice of Turkey, Emirler, signing on: 9880 kHz, The ABB transmitter SK5SC3-2P is switched to full poer [500kW] in five steps within about three seconds.

Recently, I came across the different sign-on ceremonies of different transmitters. The idea is to understand this workflow in which obviously several stages of the transmitter are switched on consecutively. See at the top one example, where Voice of Turkey is swithcing on their transmitter on 9880kHz in five steps within about three seconds.

The diagram was made with Simon Brown’s unique software SDRC V3. I used the Signals Analyser module, providing a (needed!) time resolution of down to just one millisecond, or 1000 values of level vs. frequency in just one second! These data (CSV) had been exported and visualized in QtiPlot software.

I would like to encourage other people to join these observations. One goal can be toi fingerprint no only a transmitter, but also the workflow of the people at the transmitter. Please refer to this website for a database of broadcasters and their transmitters plus galore of associated data.

In the meantime, I already observed a couple of different workflows/transmitters. Please keep in mind that all these measurements (better: estimations), of course, are prone to fading. You may also see some effects during sign-on in the spectrogram, see below.

Radio Saudi, signing on, 17’615kHz at 12:57 UTC on 02APR2020. You clearly see at least three different steps of power plus some transient when switiching to full power.

RX-666: Listen to A Gamechanger!

Flying high: RX-666

Since Marco Polo, combinations of Italian and Chinese had proven fruitful. The Dragonfly RX-666 is such a combination or, at least, a very special “kind of”. It is a 16bit SDR, ranging 1 kHz to 30 MHz in a row with 16 bit resolution – plus some extra above 32MHz (1.5/1.7GHz) by the help of an R820T2-chip of RTL-SDR fame, but 8 bit only. Priced not much over US-$ 200 (if that) at some ebay sellers, it is a real gamechanger, offering for the first time 32 MHz streaming via USB3.0 at 16 bit resolution to ensure a competitive dynamic range.

32 MHz at a glance! And just 15% CPU load on an i7.

It has been built around LTC2208 chip and seems a clone, a twin or a pirate piece of a concept, literally layed/laid out by Oscar Steila, IK1XPV, an electronics engineer from Turin. Über-DXer Bjarne Mjelde has diven deep into the story and the receiver itself. I don’t want to repeat what he found out in only my own words. You simply must read his story here, and I can stress each and every word of it.

In this blog, I may add only some audio clips to give an impression of the reception quality in Northern Germany on the evening of August 11 and the morning of August 12, 2020. Antenna, as always, is the professional active dipole MD300DX, vertical with 2 x 5 m legs. Recordings were made with HDSDR software, but replay done with SDRC V3. Both, Bjarne and Oscar, helped me to get the SDR flying at all. Without their friendly hand, it would have been only another heavy paperweight on my desk …

Now for some twelve audio clips:

IRIB Ardabil/IRAN, 1512 kHz, 20:00 UTC in Farsi
RUssian Aero Net with control station like Samara and Ural, 4712 kHz, 20:05 UTC, each running 1kW with a low-hanging dipole; in Russian.
Echo of Hope, clandestine from Suwon/South Korea on 4890 kHz at 20:00 UTC in Korean.
BPM, Chinese time signal station in AM with CW-ID and voice ID in Chinese on 5000 kHz at 19:59 UTC. Please compare to reception during the same time on 10’000 kHz below.
Voice of America/Botswana on 6.080kHz duly doing for what they are payed for: Hail to the Chief, hail, hail, hail! 20:00 UTC
The other chief: TWR Botswana on 6130 kHz in Kimbundu language – Amen. 20:00 UTC
Singapore VOLMET on 6676 kHz with weather e.g. for Kota Kinabalu, Bali, Penang and Singapore/Changi, 19:50 UTC
BPM, Chinese time signal station in AM with CW-ID and voice ID in Chinese on 10’000 kHz at 19:59 UTC. Please compare to reception during the same time on 5000 kHz up.
World Christian Broadcast from Mahajanga/MALAGASY transmitter on 11’965kHz at 20:00 UTC
BBC via their Atlantic Relay/Ascension on 12’095kHz, 20:00 UTC
Radio Kuwait from their homeland on 15’530kHz in Arabic, 05:00 UTC
China Radio International from Kashi/Xinjiang on 17’720kHz in German

The range above 32 MHz is covered by an R820T2-chip at maximum streaming bandwidth of 8MHz only. Please see below a screenshot of a part of the FM broadcast band:

FM broadcast is covered with an R820T2-chip at a maximum streaming bandwidth of 8MHz only. Here you see a part of the FM broadcast band.

FM-DX: How to Identify very short openings – a few examples

42 seconds in a recording of 12 hours length – a “blob” in V3’s “Analyser” module reveals a DX chance.

In the last weeks, I had used Sporadic-E conditions to stroll a bit in the FM broadcast band in search for DX. Elad’s FDM-S3 covers the whole 20 MHz wide band, and Simon Brown’s SDRC V3 software again provides an unique and most valuable tool to dig out DX. Antenna is an active Dressler ARA-200 (R.I.P.).

This blog entry shows how to make use of short openings of only some (ten) seconds.

First step is to record the whole FM broadcast band for hours on external HD. Then you make up so-called “spectrograms” by V3’s Analyser module. This provides you with a picture of activity (signal strengths color-coded) over time and frequency – see screenshot at top of this blog.

Scrolling through this spectrogram, you can make out even the shortest openings. Just click onto one of them, and the software instantaneously tunes into it. The sensitive RDS decoder of V3 is doing the last step – showing its RDS identification.

The short video below gives one example from a recording of June 26, 2020. On 91.8 MHz, I received semi-local transmitter NDR 1 NDS at Visselhövede (5kW@67 km distance), with “Stand by me”. From the spectrogram, I saw a “blob” (see screenshot at the top of this blog), stretching over around 40 seconds. It turned out to be Algerian’s Akfadou transmitter with Chaine 2 programme, 70 kW ERP@1’810km distance! RDS did tell me. Just have a look at the short video below which was made with V3’s video recorder …

First “Stand by me” by a local transmitter, then CHAINE 2 drops in for about 40 seconds, after the local transmitter takes over again.

V3 software provides also an a-symmetrical tuning of bandwidth, even at wide FM/BFM. This is important to identify some stations “in the clear” – if they are prone to some spillover from a local/regional station right on an adjacent channel. The following example spots Radio Marca/Mallorca from Spain on 91.6 MHz, suffering not only from a a strong local just 100 kHz below, but also from a very short appearance “out of the blue”, to where it disappeared again after less than 30 seconds. The latter is shown in the spectrogram, made by the Analyser, where I magnified the small/short signal of Radio Marca over 1’541 km. The video at the bottom shows how to evade the interference from the channel below to get the RDS code “B002 R.MARCA” correct.

On an empty channel, a stations pops up for 28 seconds. Pinpointed by V3’s “Analyser”, decoded as RDS “B002” Radio Marca from Na Burguessa/Mallorca in Spain by the RDS decoder.
With a strong local just 100 kHz below, a-symmetrically tuning the bandwidth helps to identifythe very short pop-up of Radio Marca/Mallorca on 91.6 MHz by RDS.

Sometimes propagtion is too short for any identifcation, neither RDS, nor by announcement. Take the next screenshots as example: The spectrogram shows some very short openings revealing similar pattern which cropping the recording (Crop – > Apply) confirms. It turns out to be an English-speaking stations for a maximum of ten seconds. Parallel listening reveals the same programme on the following eight frequencies: 88.3MHz, 88.4MHz, 88.5MHz, 88,7MHz, 88.9MHz, 89.1MHz, 89.7MHz and 89.8MHz. The only intersection turns out to be Raidió Teilifís Éireann from different locations with their Radio 1 programme.

Up to ten seconds in a ten hours’ recording, marked by a rectangle in the spectrogramme: whodunit?
All nine stations carried a broadcast in English, eight of them in parallel, only that on 89.6MHz remaining unidentified. The solution is easy …

RTE transmitter usually do have RDS onboard, but here the time with a modest signal was too short to raise the alarm. On the other hand, there are stations with RDS, but not programmed or even without RDS at all. Take Radio Tisnath/Algeria in Tamazight, a Berber language, as an example for the first and Radio Blagovestiye/Russia as an example for the latter:

Radio Tisnath from Djebel Tissalah/Algeria [2’091km] should carry RDS-ID of “2202 CHAINE2”, which didn’t pop up – in spite of the good signal. At least a station identification was heard, alas, a bit distorted after a programme in Tamazight in the clear
As with all OIRT band stations, also Radio Blagovestiye from Voronezh/G-Tsa Brono in Russia [1’984km) doesn’t carry any RDS information. You have to wait for the announcement – as here – or to collect some other information to identify such a station.

Sporadic-E Reception: Some Notes

Running from top to bottom: that’s DX! The spectrogram runs from 87.5 MHz to 94.5 MHz. The lower part shows Sporadic-E conditions around 18:00 UTC, the upper part was switched to 19:37 UTC when Sporadic-E had largely disappeared. 29May2020.

When HF collects new power for the autumn season, it’s time to thrown an ear onto VHF. I did so in May 2020, and the spectrogram at the top should give you an impression of the power and glory with with Sporadic-E fills the ORT band and the FM broadcast band. Having published some audio examples from both bands in the two recent posts, I now want to make some comments on this exciting propagation mode.

One signature of Sporadic-E is a highly selective propagation in respect to geographical regions – resembling a laser pointer. Please find below an example of just 90 seconds on 93.9 MHz on 29May2020, around 18:00 UTC (the vertical interruption at the last quarter of the audio spectrogram. It starts with a powerful-modulated, yet unidentified, Italien station with pop music. Then, Radio Constanine from Kef El Akhal (per RDS 2425) takes over with a distinctive (lower) sound, gevoerning the channel for a time, until the Italian comes through again. If play the audio clip and following its spectrogram in parallel, you surely will see what I mean.

93.9 MHz: Two stations on one channel, see text. The vertical frequency is in the logarithmic style to enhance the visibility of the most important speech formants. Listen to audio clip below.
Here you can listen to what is shown in the spectrogram above: two different stations fighting on 93.9 MHz.


Parallel listening on two channels is an essential tool to identify the same station on different channels. Place one (e.g. the left) audio channel on one frequency, and the other audio channel with a 2nd RX on the other (in this case: right channel). This can be done easily with SDRC V3 software. There will always be a time lag between both channels for at least two reasons: the main reason is that two frequencies are usually coming from two different locations, fed over different lines from the studio which causes a slight time difference. The other reason: different RXs in SDRC V3 software ore not phase-synchronized, so there is a small difference. Another difference might occur from different propagation time from two locations (300 km = 1ms!).

The screenshot below shows a typical setup: on 87.7 MHz a station in Arabic was heard. It was set onto RX1/left audio channel. To identify this station, RX2 was set to the right audio channel. Leaving RX1 on its frequency as the reference channel, RX2 was tuned to other channels with Arabic programme. The first hit was made on 87,6 MHz, second on 90,8 MHz, third on 92.5 MHz – all carrying the same programme. Hence, it was very likely SNRT Al Idaa Al-Watania from Morocco from four different locations at distances from 2312 to 2613 km.

Searching parallel programs: right (as basic) audio channel on 87.7 MHz, left audio channel on 90,9 MHz showed programmmes being (largely) in parallel – see the spectrum, and listen to the audio, both below.
Spectrogram of both channels of the audio clip below: left audio = top, right audio = bottom In the first few seconds, including the time-beeps, 87.7 MHz produces “Radio Chlef” from Bou Kadir/Algeria (1963 km), according RDS. Then SNRT Al Idaa-Watani from Midell (2498 km) takes over.
Listen to the above spectrogram in stereo. Soon you will hear that 90.8 MHz lags a bit in time. And that in the first seconds both channels are not in parallel.


The Radio Data System RDS provides an identifcation and often some additional information. First, you see the “Programm Identification Code – RDS-PI”. This is used to support an automatically scan of the receiver to tune always the best channel of this programme. Hence, it designates a programme which is used throughout a chaine of programmes. The “Programme Service Code – PDS-PS” needs a bit longer and gives, if programmed, additional information. As the RDS signal sits on edge of the channel and is quite slow, it is a bit delicate to receive from weak stations under interference. The first example below gives a full-blown RDS signal from a local broadcaster, followed by some RDS signals from DX stations.

Here you see all elements of an FM multplexed (local) stereo signal. The double-peak on the righ is the DSB-modulated RDS signal.
A selection of received RDS signals, in reading direction: 92AA Top Albania (1356 km), 505F Radio Sound/Italy, 5264 RDS/Italy (1304 km), 11DE Radio Epirus/Greece (1648 km), 5201 RAI Radio 1 /Italy (1635 km), Radio Soummam/Algeria (1810 km), E2ED Europa FM/Spain (1364 km), 2202 Chaine 2/Algeria (1802 km)

Fading can be nerve-wrecking. Stations come and go. And they reliably go at top of the hour when the listener expects a station identification … Below I compared the signal from a still near-regional transmitter at a distance of 83 km with that of Radio Constatine/Algeria, 1802 km away. The grey block marks the limit, whre Radio Constanine can be demodulated.

Sporadic-E: Some Examples FM-Band/Broadcast

Three in a row: Reception from three stations from Algeria at the same time over a distance of about 1’800 km on 31May2020, 12:00 UTC

Again, Sporadic-E reception. Now some examples from the FM Broadcast Band (87.5 to 108.0 MHz), as received in spring 2020 at my location in Northern Germany. See my former post for examples from the OIRT FM Band.

87,9 MHz: Radio France Culture, Porto Vecchio (1208 km), ID, 31May2020, 12:00 UTC.


88,8 MHz: Radio Annaba, Souk Aras/Algeria (1791 km). ID in Arabic, 31May2020, 15:00 UTC


90,4 MHz: Radio Setif FM, Setif/Algeria (1829 km). ID in Arabic, 29MAY2020, 18:28 UTC


91,9 MHz: Rádio Comercial, Serra de Bornes/Portugal (1772 km). ID-jingle in Portuguese. 29May2020, 17:50 UTC.


95,1 MHz: BBC Radio 4 FM from Eitshal/Isle of Lewis (1224 km). BBC-ID, 31May2020, 15:00 UTC.


94,1 MHz: Top Albania Radio/Shkoder (1356 km). ID in Albanian. 29May2020, 17:00 UTC



100.7 MHz: Radio Coran-Algerie from Kef El Akhal [1802 km]. ID in Arabic. 31May2020, 12:00 UTC.


102,3 MHz: Nevis Radio/Mallaig, UK (1139 km). 29May2020, 11:00 UTC.


92,8 MHz: Radio Energy, Kiew (1428 km), ID in Ukrainian, 31May2020, 15:53 UTC.


97,8 MHz: Radio Azzura, Marsala/Sicily (1640 km). ID in Italian, 31May2020, 15:02 UTC

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