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.]
The original software for Elad receivers provides a very useful feature, resembling the old radio scale: it inserts some station data from a list on their proper place in the spectrum – see screenshots above (utility) and below (broadcast).
You may invoke several lists like EiBi and your own memories. These list just must comply to the data standard, Elad had set. You may also set up your own list. If you sepcify a transmission time other than 0000-2400, only the stations active at this time will pop up.
With Bernd Friedewald’s (DK9FI) International Listening Guide there is such as matching list available providing 31.000+ entries of brodcast as well as of utility stations. Bernd is a long-time professional in the field of broadcast monitoring and international consulting in this field. You may also edit this list.
(Disclaimer: I have no commercial relationship with ILG, and bought the data like everyone.)
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.
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 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.