Category Archives: Modes

Wake up – ICAO Selcals

If you ever had an ear on the aero bands, you are already familiar with ICAO Selcalls. With this 2 x 2 tone signal lasting for about 2,2 seconds, a Ground Station alerts a specific airplane to open up for communications. The short video on top of this page shows a typical initial contact, where Ground an Air are testing the Selcal.

This paper (click this hyperlink) describes on three pages with nine illustrations, one video and one audio the procedure and gives some background information. These may improve correct decoding of the somewhat delicate signals, as it will show how to look up the Selcal and follow the flight. BTW: It is planned to extend the pool of 16 tones to 32 tones by September 1st, 2016.

P.S. Remember to save the PDF and open it with a recent version of Acrobat Reader. Otherwise the multimedia (video, audio) will not work!

Monitoring, State-of-the-Art: In a Nutshell

As I was asked for a look onto my monitoring workbench, I decided to write it down. It’s not to show “the real stone”, but an invitation for discussing efficient workflows which State-of-the-Art technology has to offer.

This PDF of 13 pages contains 25 hopefully instructive illustrations to comprehend my approach to monitoring; or, in this case: Utility DXing. Part of this PDF is also a 2:50 video, showing how to stroll between aero channels and to decode ALE. This video is also placed on top of this page.

The paper explains in detail the advantages of leafing through recorded HF files using the technology of the “living sonogram”. It also discusses some efficient strategies of voice and data reception, eventually touching even documentation.

To make use of the video content, download it on your hard disk, save it and open it by the most recent version of your PDF reader. It works on a PC as well as on a Mac. You can download it here.

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 jeweils als Titelgeschichte in der April- Ausgabe 2017 der Fachzeitschrift  Radio-Kurier – weltweit hören und in der Mai-Ausgabe der Fachzeitschrift Funktelegramm veröffentlicht.]

Code3-32P: A truly professional Decoder – Tested in the real World

Abbildung 12

HOKA’s Code3-32P is a truly professional decoder in a price class which will fit into most hobby budgets. Together with Roland Proesch’s Frequency Manager it makes an even stronger companion (with your Perseus SDR) in decoding and analyzing many digimodes.

This paper is an introduction into this decoder. It’s written in German, but 17 illustrations plus Google’s Translator will help you.

Nach wie vor ist der Code3-32P von HOKA ein starker Decoder und ein zuverlässiges Analysewerkzeug für Digimodes zu einem verhältnismäßig kleinen Preis. Zusammen mit dem Frequency Manager von Roland Proesch bildet er ein nochmals stärkeres Gespann (dann gemeinsam mit dem Perseus SDR).

Dieses deutschsprachige PDF bietet auf 18 Seiten eine reich illustrierte Einführung in den Code3-32P – mit Beispielen aus der wirklichen Welt, jenseits des Deutschen Wetterdienstes …

The best Digimodes: Test reveals surprising results

Disturbed

Digital communications with digimodes is a very efficient tool of HF communications. Hams are using RTTY for decades. Since the advent of PSK31 in late 1998, there have been developed a lot of digimodes with special applications in mind. Albeit, RTTY and PSK31 are still very popular.

When I asked myself: “What’s the best mode?”, I couldn’t get a reliable answer. And, really, it depends.

As a result, I made a setup for testing some chat modes on HF channels which are very much different from just flat noisy (AWGN) channels. The results were very much surprising: There are by far better alternatives to RTTY and PSK31 (see table above, reflecting some of the results).

This paper deals with setting up a real-world testbed and presents some results. Anyone is welcomed to replicate the test and/or extend it with other modes. Recent software of W1JHK has made the workflow much easier and faster since then.

FUNcube Dongle PRO: How to get the most out of it, HF-wise

DynamikFCD_E

FUNcube Dongle PRO is an USB stick, containing a great SDR at a low price of around 200 Euros. It makes a fine choice if you are seeking a serious start into the world of HF & SDRs.

I had much fun in gettingout the most of it regarding the HF bands. My enthusiastic experience resulted in this paper: 16 pages with 43 figures showing how to use this great little SDR in receiving, decoding and analyzing. Many aspects are covered, with broadcast, Amateur Radio and Utility DXing only some of them.

The key success factor in the congested HF bands is shifting the quite limited dynamic range to it’s proper place (see Illustration from the paper on top). This simple technique results in stunning reception of even Decoding delicate digital signals of 2.400 baud out of Tahiti in Germany!

This paper explains in detail on how to get the most out of this receiver.

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