Category Archives: Broadcast

Airspy & SpyVerter: A serious love affair

24ch

24 broadcast channels demodulated in parallel on shortwave – And Airspay and SpyVerter do need just a quarter of PC’s power!

For a much too long time, I had overlooked Airspy and the matching up-converter, namely SpyVerter. Found no explanation for this my blind spot. Now I am focusing my view onto this 10-bit SDR, covering 24 MHz to 1.800 MHz (just Airspy) plus 1 kHz to 60 MHz by help of Spyverter (+120 MHz). What I see from my first tests is a sensitive combo with a surprisingly lot of dynamic range, ending up in clear recpetion of up to a nearly 10 MHz wide band. This may be recorded and eventually played “as live”.

I am still tuning up and down the bands, trying this and that. It will end up in a test report in due time. For now, just have a look at the screenshot on top, showing 24 demodulators (Synchro-AM) in parallel, covering many broadcast channels in English from Asia. Have also a look at the fine print on the right at the bottom: this all needs just the quarter of the power of an able PC.

So, for now, just a a sentence at half-time: Don’t overlook this combo if you are in search for a “low cost, high perfomance SDR”. Yes – that’s exactly  the way Youssef and his team advertise it, but it is one of the rare cases where such a claim meets reality. Stay tuned.

LimeSDR: First Experiences on HF

One hour in the 20 m ham radio band with LimeSDR and SpyVerter, zoomed out of a one hour’s recording of 30 MHz width. Antenna: quadloop of 20 m circumference.

LimeSDR is a Crowdsupply project – delivering an SDR which covers 100 kHz to 3.8 GHz with bandwdiths of up to 2 x 30 MHz. I was interested almost exclusively in the range 100 kHz to 30 MHz. The board arrived on March 17th, and I already have done some tests with it. From these very first results & a recommendation:

  • Installing is easy (W10), if you follow the instructions.
  • Without modification, LimeSDR is simply useless on HF. It’s deaf near to a dummy load.
  • The producer recommends a “modification” by just removing one SMD. Then some life came into this range. But it was hard to sort the ghost stations from the real ones.
  • Even a low-pass filter from Heros didn’t helped that much.
  • Just before selling the board on ebay, I connected the antenna first with Spyverter – a state-of-the-art up-converter with an IIP3 of +35 dBm, transferring the band of 0 – 30 MHz to 120 – 150 MHz. This is a range, where LimeSDR sees some light.

So, if you are disappointed by the near-non HF performance of naked LimeSDR: an able up-converter will change the game. Recording and sonagrams had been made with SDR-Radio.com V3.

30 MHz live with LimeSDR and SpyVerter shows that it generally works. Same antenna as above.

“Ghost signals” make it sometimes difficult to distinguish them from real signals. This sonagram has been made with SpyVerter. Broadcast stations are easy to find out (in their majority). But it gets difficult to sort the ghost stations from the few real ones in the left part.

 

Medium Wave Adventures

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China & Taiwan, Korea, Afghanistan – “That’s my desire” [studio take by Chuck Berry; November 19, 1958]

Eventually, I couldn’t resist the siren’s songs of Christoph, OE2CRM. These consist of breathtaking audio files of some marvels he received at his unique remote receiving station.

Throughout my DX life, I had been an addict more to HF than to medium wave. But Christoph’s results made the trick to convince me also trying this band. Still slowly groping forward in this band like a white sticker, I liked even the first results a bit. Please find below a hopefully growing collection of audio clips. They were received with my loop of 20 m circumference, mostly with Wellbrook’s active head ALA100LN for these large aperture loops. Receiver is mainly Perseus or Elad’s FDM-S2. They all were received in Northern Germany. Let’s go, and don’t forget to to click the READ MORE button for – listening to much more!

1610 kHz CAN  CHHA – La Voces Latinas in Spanish, Toronto, 6,25 kW, 2017-01-09, 06:23 UTC

1575 kHz THA  VoA with ID/Yankee Doodle, Ban Phachi, 1000/500 kW, 2016-11-29, 15:00 UTC

1566 kHz KOR  HLAZ FEBC in Chinese, Jeju, 250 kW, 2016-11-20, 14:44 UTC

1557 kHz TWN  Radio Taiwan International, “RTI News”, Kouhu, 300 kW, 2016-11-20, 15:57 UTC

1521 kHz CHN  China Radio International in Russian, Ürümqi, 500 kW, 2016-11-20, 14:00 UTC

1512 kHz IRN  IRIB Radio Ardabil in Farsi, Ardabil, 50 kW, 2016-12-10, 16:30 UTC

1510 kHz USA-MA  WMEX, Boston, 50 kW, 2016-12-07, 07:00 UTC

Read more

PropLab 3.1: How Propagation really works

 

Fergana_DK8OK_3DRayTracing

The software’s unique feature is 3D raytracing, showing an anatomy of propagation (see text).

HF propagation software seems to be full of mysteries. But its all about modeling physics. There are several models around, the most prominent surely is VOACAP, followed by ASAPS. VOACAP comes in very many different tastes like e.g. PropMan 2000 or ACE. It often has been coined to be the “Gold Standard” among hams and professionals as well. VOACAP gives reliable results on a statistical base for a month, whereas ASAPS returns propagation based on the current conditions of a day. It also gives propagation for an aircraft en route during its flight and takes at least a bit care of multi-path propagation which may degrade digital modes. Both work offline as online, and they are fast.

[Einen ausführlichen deutschsprachigen Test mit vielen Screenshots und Beispielen habe ich in der Januar- Ausgabe 2017 der Fachzeitschrift FUNKAMATEUR veröffentlicht.]

PropLab is giving you a much smarter view on what is really happening on a specific day and time at a specific path or area. It relies on the International Reference Ionosphere (IRI 2007) and uses the ray tracing technique. In short, PropLab is automatically fetching all relevant space weather data (not just sunspots) from scientific sources of the internet to model the ionosphere with its different “layers”.

You then give in your path, antenna etc. in a well-supported way. After having started “ray tracing”, PropLab lets refract rays at exactly this ionosphere with its high granularity and some real-world effect like tilts of layers which will result in e.g. propagation off the great circle. It will also beautifully show effects like focusing and gray line propagation, including Pedersen’s long ranging ray with time resolution up to one second – rather than one hour as that of VOACAP.

Read more

20 MHz HF: “HackRF One” on Shortwave

world Kopie

The world is full of software-defined radio (SDR), but HackRF One has a rather unique position – thanks to its vast maximum bandwidth of 20 MHz. With an up-converter, this combination covers more than 70 percent of the whole HF range from 3 to 30 MHz. Even better: with proper software you can record and play this enormous band!

However, this stunning bandwidth is achieved by a moderate resolution of 8 bit, resulting in a dynamic range of just nearly 50 dB. Or the half of SDRs like Elad’s FDM-S2.

Anyway. I wanted to know in practice what you can actually do with such a set at a budget price plus mostly free software. The results surprised even me: Properly used, this combination convinced as a quite decent performer on HF! The world map above shows some of the stations received with the set (see insert bottom left) to test its performance.

I laid down my experiences and recommendations for best reception in a paper of 17 multi-media pages full of examples – including 55 screenshots, 21 audio clips and one video. The PDF shows how to optimize reception of broadcast, utility and amateur radio stations. It covers many examples on how to analyze recordings, to decode data transmission with free software plus live decoding of 14 channels in parallel. It also gives some examples of combining HF reception with the internet, e.g. regarding the reception of signals from airplanes (ARINC, HFDL) and vessels (GMDSS).

My experiences really left me enthusiastic about this set.

You may share this enthusiasm and download the PDF of 43 MB here. Save it on your hard disk or USB stick, and open it with a most recent Adobe Reader. Otherwise, the multimedia content will not work.
[Einen deutschsprachigen Test  habe ich als Titelgeschichte in der April- Ausgabe 2017 der Fachzeitschrift  Radio-Kurier – weltweit hören veröffentlicht.]

Multi-Channel Monitoring

Matrix_24_RDS

In recent posts, I already wrote about my experiences with Simon Brown’s software SDR Console V3.0. It matches most SDRs, delivers now up to 24 virtual receivers and is capable to run multi instances, i.e. you may run several SDRs on one PC in parallel.

That’s exactly what I did when I connected three SDRs FDM-S2 to a PC, running 35 different ARINC-635 channels in parallel resulting in 68.000 decoded messages. It worked brillantly.

And there is much more, e.g. recording and playing 24 audio channels from broadcasters throughout 20 MHz (the whole FM band!) with hardware RFHack One.

This paper provides a hands-on and step-by-step guide for some vital monitoring tasks like:

  • using up to three receivers on one antenna and one PC
  • working with multi instances of GUIs
  • working with multi instances of software decoders like PC-HFDL and MultiPSK
  • carefully planning a monitoring session
  • analyzing  the decoded results and apply some basic statistics on 68.000+ messages
  • record and play 24 channels incl. RDS data within a bandwidth of 20 MHz on the FM broadcast band plus on HF with RFHack One (see screenshot on top of this page, “Matrix” mode)
  • … and much more

Rundfunkempfang auf Kurzwelle: Eine Einführung

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Nach wie vor sprechen internationale Rundfunksender noch mit einer starken Stimme auf Kurzwelle. Diese Einführung beschreibt auf 33 Seiten und mit 31 instruktiven Abbildungen sowie vielen integrierten Hörbeispielen, wie diese Kommunikation zwischen Sender und Hörer funktioniert. Anders als sonst, wird hier auch die Planung aufseiten der Sender berücksichtigt – und was wir Hörer davon haben.

Schon das opulente Cover (siehe oben; Dank an Christoph Ratzer, OE2CRM!) zeigt, dass in diesem Thema weiterhin jede Menge Musik steckt!

This 33-pager in German has been written as introduction into international broadcasting on shortwave. It covers frequency planning of the transmitters as well many aspects for us listeners. 31 illustrations and many sound example may make it digestible even for people who don’t speak German.

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