Tag Archives: SDR

Rundfunkempfang auf Kurzwelle: Eine Einführung

Kleiner Streifzug-1

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.

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

IntruderWatch_Workflow1

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.

Perseus & Markers: Great Tools for analyzing Propagation!

Ionosphäre_CHU

The Perseus SDR comes with a software, where you may define up to eight markers. Each of them measures the level of the signal at distances of 100 ms to 5 seconds and writes it into a CSV file. This is the base for further analyzing these data, i.e. propagation. See such an analysis of the fade-out of CHU on 3.330 kHz on top of this page.

With an (active) antenna delivering a constant antenna factor over specific range – as all professional antennas do, e.g. RF-Systems’s DX-1 – you may also switch to logging the field strength of the signal in dBµV, rather than the input level in dBm.

The first paper presents a general introduction into this concept. It has been translated into English by Guy Atkins.

The second paper, in German, goes more into the depth of analyzing the data. But it’s 13 illustrations will make it under stable also to readers who don’t understand German.

Titan_SDR: New Approach in SDR, 40 Channels at once

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With it’s TitanSDR, Italy-based company Enablia has a new approach in SDRs: This receiver delivers up to 40 demodulated channels in different HF bands.

Applications are numerous, e.g. checking GMDSS channels in different maritime bands (see above), monitoring many ALE channels at once, control broadcasters with all their parallel frequencies etc.

This paper delivers on 26 pages and with 44 illustrations a detailed hands-on explanation of this new approach. It is enriched with some audio clips. It shows real-world example of receiving brodcast, amateur radio and utility stations. And it assists you in setting up a couple of decoders at once to monitor many channels in parallel.

Caveat: Embedded multimedia content will only work with the most recent version of Adobe`s Acrobat Reader. And you have to save the PDF on your device (hard disk/stick), to make use of these multi-media.

Why Ham Radio is that conservative? Warum nur so konservativ?

Dino

It’s only in late 2015 that the first SDR transceiver of one of the big japanese players hit the market. Until then, there never had been even a receiver of this kind from these sources.

Technological progress seems to come from the edges, from Russia, Italy, Switzerland, and the U.S. For many decades, hams do have their difficulties in accepting new technologies and techniques – may that be the use of SSB, CW as a mandatory, the PC or advanced digimodes.

The majority of them remains stunningly conservative. And their media lives a role model which they simply follow.

The advent of the IC-7300 reminded me of a paper, written originally in German, already in 2007. There I tried to explore this attitude. It also tracks the way of professional technology, of which ham radio technology increasingly slower lagging behind it.

Adam Farson (VA7OJ/AB4OJ) did a great job to vividly translate the text into English, read it here.

Warum sind die Funkamateur nur immer so konservativ? Das fragte ich mich zuletzt 2007 angesichts ihrer Skepsis gegenüber der SDR-Technologie. Daraus entstand eine Analyse, an die ich mich anlässlich der Ankündigung des IC-7300 im Herbst 2015 wieder erinnerte.
Hier ist sie auf Deutsch nachzulesen, und immer noch erschreckend aktuell.

R&S EB500: The Über-SDR

EB500_GUI1

It’s easy to look into the future of hobby receivers: just look on what the professionals are doing! Since the days of AEG-Telefunken’s E-1800, I do follow this advice. Where are the professionals yet better, and what may the amateur world see at their receivers the coming years? Hence, I was glad to test Rohde & Schwarz’ EB500 for some weeks; plus their professional decoder GX430. Even more, as I visited them in Munich and talked with some of their engineers.

Alas, the resulting paper with 15 screenshots is written in German. But surely Google Translator will be your friend.

Wie sieht die Zukunft der Hobby-Empfänger aus? Diese Frage interessiert mich seit den frühen 1980er-Jahren, als ich den damaligen weltbesten Receiver testete, den E-1800 von AEG-Telefunken. In welchen Punkten sind die Profis besser, und was können wir in der Hobbypraxis damit anfangen? Schließlich: Was kommt auf uns in den nächsten Jahren zu? Deshalb freute es mich, den EB500 von Rohde & Schwarz für ein paar Wochen zum Test gehabt zu haben – zusammen mit dem Profi-Decoder GX430. Mehr noch, denn ich konnte einige der Entwickler in München sprechen und so auch einige Hintergründe erfahren.

Das deutschsprachige Manuskript des Tests: hier klicken.

Solar Eclipse 2015: Some signals did improve, some didn’t

23k4

The Solar Eclipse on March 20th, 2015, provided some unique Monitoring opportunities in Europe. It was the first time that broad parts of the spectrum could have been recorded and analyzed even by hams.

I recorded the range from 0 to 2 MHz to analyze the effects of the eclipse on different frequencies: on VLF signals dropped significantly (see the W-shape level of DHO38 on 23,4 kHz above), whereas on medium wave signals did improve.

This paper covers my observations in e.g. 29 illustrations and some audio files.

Caveat: Embedded multimedia content will only work with the most recent version of Adobe`s Acrobat Reader. And you have to save the PDF on your device (hard disk/stick), to make use of these multi-media.

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.

Living Sonagram: A revolutionary tool for Monitoring

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Monitoring of wide frequency ranges can be an art. And hard work, too. The technique ot the “Living Sonagram” makes this task easy:

  • record a frequency range of up to 10 MHz, for e.g. 24 hours or less or more
  • define a range of time ad frequency you want to analyze offline
  • build up the “Living Sonagram”
  • tune. demodulate, and decode in this whole range just with your mouse (see screenshot on top)

You must see this to believe it!

The Software has been developed by Simon Brown.

I wrote this paper as a step-by-step introduction into this technique.

You may also look this video on this topic.

Active Antennas, Interference by Power Supplies: A Test

PS_Original_Farnell_Straton_30MHz

If you don’t have much place, an active antenna is a fine alternative. You have to concentrate just on the signal-to-noise ratio, not so much on the S-Meter.

A recent test of some pre-production and (semi-)professional active antennas did not only had stunning results, but also draw my attention to noise coming from the switching power supplies of SDRs.

I did some investigations on both the performance of two active antenna vs. a quad loop of 20 m circumference and the noise coming from switched power supplies vs. two linear regulated power supplies. Read more

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