Category Archives: HamRadio

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

ASAPS: HF Prediction online & free!

Flight AF 128 from Paris to Beijing: What is they best time/frequency combination to communicate with Stockholm AOCC on HF?

Flight AF 128 from Paris to Beijing: What is the best time/frequency combination to communicate with Stockholm AOCC on HF en route?

 

HF prediction seems to be a somewhat neglected field among short wave listeners, as well as hams. At the same time, some knowledge of how propagation works on specific paths or into defined areas will greatly enhance your hunting success. If you have considered the somewhat flat learning curve of some software as an obstacle, there now is no excuse. With ASAPS’ recently even more improved online services, you are on the sunny side of HF right now.

I had written a short paper explaining how this free service can be used especially for Utility DXing. If you also ever wanted to know the relation of a waste paper basket and multi path propagation, please download this PDF (7 pages, 22 illustrations) here.

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

DSC_night

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.

Five Mongolians on Long wave

Mongolia_209_rays_2200

Since I visited Mongolia in 2001, I fell in love with this country. Hence, reception of all their radio stations on long wave caught my double interest. With some help of other listeners, I managed to receive all stations and analyzed their reception. Without any 100 g of Chinggis Khan Vodka, to which I surprisingly bumped into at Sarazul at Warnemünde in late summer 2015 …

Read this paper, to get also some information on how to receive and analyze stations which even might be too weak to hear.

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.

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.

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.

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