Tag Archives: Digimodes

Ham Radio: Intruder Watch, State of the Art. Oder: Bandwacht nach dem Stand der Technik.


HF spectrum is precious. Each user has to obey specific rule – of ITU and his own country. For best communications, there have been assigned exclusive band for different user groups. The amateur radio bands for hams are among them.

“Intruder Watch” is to look out for stations which do have no legitimation to transmit on the frequencies they use. These signals can originate from broadcasters, bad transmitters with their fundamental on a legitimate frequency, broadcast, military (OTHR RADAR!), diplomatic …

Amateur radio with it’s relatively small transmitters and antennas is especially prone to be disturbed by intruders. SDRs, software and a specific workflow (see illustration on top of this page) offer an as easy as complete monitoring of such bands on a 24/7 base at low costs.

This paper shows how that can be done: monitoring and analyzing on a professional level.

Professionelles Monitoring spürt zuverlässig sämtliche Bandeindringlinge in Frequenzbereichen auf, wo diese nicht hingehören. Das ist, sogar auf 24/7-Basis, auch mit Amateurmitteln möglich. Das Werkzeug sind ein SDR, Software und ein spezifischer Arbeitsprozess.

Hier kannst Du das Paper auch auf Deutsch lesen, wie alles funktioniert – Schritt für Schritt.

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


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.

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